Arctic Sea Ice : Forum

Cryosphere => Arctic sea ice => Topic started by: Lord M Vader on March 19, 2018, 08:12:14 PM

Title: The 2018 melting season
Post by: Lord M Vader on March 19, 2018, 08:12:14 PM
As the SIE has dropped the last few days and the forecast calls for southerlies to enter Berings Sea now I think we can call the maximum and also declare the 2018 Melting season started! And I think a lot of people here thinks it quite fitting to start the melting season thread with a century break... :)

Personally, I think we will end up somewhere around 4,5 Mn km2 by the middle of September.

Now, let's get this show on the road! :)
Title: Re: The 2018 melting season
Post by: Neven on March 19, 2018, 08:23:36 PM
If JAXA drops tomorrow and the day after that, I'll unlock this thread.

We must respect the maximum!  ;)
Title: Re: The 2018 melting season
Post by: Neven on March 21, 2018, 08:19:44 AM
Thread unlocked. Here we go!

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.dailymail.co.uk%2Fi%2Fpix%2F2012%2F06%2F18%2Farticle-2160944-13A9AF70000005DC-305_634x422.jpg&hash=aa63cd93a80e9590f97344759617fdce)
Title: Re: The 2018 melting season
Post by: Sleepy on March 21, 2018, 08:38:31 AM
 .
Title: Re: The 2018 melting season
Post by: A-Team on March 21, 2018, 08:55:14 AM
Winter freeze season pre-conditioning is important to summer melt season. I am just staking out some real estate here on Page One to hold year-to-date summary time series at a stable, easily navigable location, in the manner of wipneus on the piomas forum. These will be periodically updated and provide basic reference files for newcomers to the site.

Note there's considerable overlap with Neven's admirable collection of 81 sea ice graphics, the difference being only water vapor at bottom is animated and all are transient (not archived). Seven of these are not working this morning due to problems at various remote host servers.

https://sites.google.com/site/arcticseaicegraphs/

All of the animations will use the standard NSIDC map of the Arctic Ocean: the polar stereographic projection about the north pole, with Greenland in the down position. The maps will be similarly scaled to forum bounds which amounts to 650 pixels between the Bering Strait and Svalbard.

The first four of these include Ascat radar scattering off the ice from January 1st to the current date. Ice roughness corresponds fairly well to both ice age and ice thickness. At an mp4 speed of 9 frames a second (ie 9 days), ice movement is exaggerated by a factor of 777,600.

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=119.0;attach=98650;image)

The OSI SAF graphic of daily ice motion is very well done. Note it also shows open water and dodgy ice as two shades of blue, thus incorporating information that otherwise might come from UH AMSR2. The first 80 days of 2018 are shown below, both as an mp4 and as summary graphic.

http://osisaf.met.no/p/osisaf_hlprod_qlook.php?year=2018&month=03&day=20&action=Today&prod=LR-Drift&area=NH&size=100%25
Title: Re: The 2018 melting season
Post by: A-Team on March 21, 2018, 08:56:45 AM
I am just staking out more real estate here on the first page to hold more year-to-date summary time series at a stable location. These will be periodically updated and serve as basic reference files for newcomers to the site.

I'll add the best journal citations for people wanting to look more into details of how academic and agency climate scientists derive the files from satellite imagery.

The first four of these includes UH AMSR2 sea ice concentration from January 1st to the current date. This is similar to ice area and extent but has much higher nominal resolution, up to 3.125 km, and provides both a detailed land mask and a daily open water mask. This time of year, most of the Arctic Ocean has 100% sea ice concentration (pure white)so the time series mostly shows solid white. That will change though on the periphery as the melt season progresses.

On the technical side, it's feasible to change out the bright red for a less distracting color, change out the white to distinguish areas at less than 100% concentration, count and graph pixels of open water, add back the color key and so forth. Unfortunately the netCDF file is not georegistered and so the map cannot be redrawn without the lat,lon lines or switched to a linear gray palette.
Title: Re: The 2018 melting season
Post by: A-Team on March 21, 2018, 08:58:39 AM
More winter pre-conditioning data relevant to summer 2018 melt season will be presented on this third bit of Page One real estate. The data summaries below will be periodically updated to serve as convenient reference files for newcomers to the site.

The third set of four of these will include various sea ice thicknesses from January 1st to the current date. The first is SMOS ice thickness (really thinness as it only shows ice to 0.5 m) from UniBremen. The scale will be added back in a bit.

The other SMOS ice thinness product from Hamburg is offered solely as a netCDF, which is better in many ways but is more arduous to animate than a png graphic. However Dryland has automated that process and we should have this time series shortly.

DMI offers a third ice thickness product based on the Los Alamos CICE model. That too comes as a png but requires a -45º rotation to re-orient it.

Piomas has a fourth ice thickness product that is thoroughly analyzed by wipneus on that forum. Here I will simply concatenate, crop and resize those bimonthly gifs.

Here is a set of links that are useful for reaching the source sites:

https://manati.star.nesdis.noaa.gov/ascat_images/ice_image/msfa-NHe-a-2018075.sir.gif

AMSR2 Hamburg sea ice concentration daily png
ftp://ftp-projects.cen.uni-hamburg.de/seaice/AMSR2/3.125km/Arc_20180316_res3.125.png
ftp://ftp-projects.cen.uni-hamburg.de/seaice/AMSR2/3.125km/Arc_20180316_res3.125_LARGE.png

OsiSaf ice drift daily 2018 03 14-03 16.png
http://osisaf.met.no/p/osisaf_hlprod_qlook.php?year=2018&month=03&day=15&action=d%2B&prod=LR-Drift&area=NH&size=100%25

Hamburg SMOS ice thinness daily nc
https://icdc.cen.uni-hamburg.de/thredds/catalog/ftpthredds/smos_sea_ice_thickness/v3/catalog.html

Bremen SMOS ice thinness daily png
https://seaice.uni-bremen.de/data/smos/png/
https://seaice.uni-bremen.de/data/smos/png/20180316_hvnorth_rfi_l1c.png

DMI_SST ice thickness daily 2018 03 11.png
http://polarportal.dk/fileadmin/polarportal/sea/CICE_map_thick_LA_EN_20180316.png

DMI_SST ice surface temperature daily 2018 03 11.png
http://polarportal.dk/en/sea-ice-and-icebergs/sea-ice-temperature/#c8099
http://polarportal.dk/fileadmin/polarportal/sea/Map_IST_LA_EN_20180311.png

GFS/Nullschool wind/temperature/pressure 8x daily 5 days out 40 frames
https://earth.nullschool.net/#2018/03/15/1500Z/wind/isobaric/1000hPa/overlay=temp/orthographic=-45.00,83.00,1008/loc=0.100,83.690

Mercator Ocean daily + 9-day forecast
http://bulletin.mercator-ocean.fr/en/PSY4#2/62.6/-85.3

WorldView ice visible/infrared daily png
https://worldview.earthdata.nasa.gov/
https://worldview.earthdata.nasa.gov/?p=arctic&l=Coastlines,VIIRS_SNPP_Brightness_Temp_BandI5_Night

RASM-ESRL ice forecasts daily nc and gif
ftp://ftp1.esrl.noaa.gov/RASM-ESRL/ModelOutput
ftp://ftp1.esrl.noaa.gov/RASM-ESRL/ModelOutput/RASM-ESRL_4UAF_ICE_2018-03-16.nc
ftp://ftp1.esrl.noaa.gov/RASM-ESRL/ModelOutput/REB2.2018-03-16.nc
ftp://ftp1.esrl.noaa.gov/RASM-ESRL/ModelOutput/REB2_plots.2018-03-16.tar.gz

Cryosat ice thickness monthly
ftp://data.meereisportal.de/altim/sea_ice/product/north/cryosat2/cs2awi-v2.0/Latest/l3c_monthly/2018/
ftp://altim:altim@data.meereisportal.de/altim/sea_ice/product/north/cryosat2/cs2awi-v2.0/Latest/l3c_monthly/2018/l3c-awi-seaice-cryosat2-nrt-nh25kmEASE2-201802-fv2.0.nc

https://sites.google.com/site/arcticseaicegraphs/
Title: Re: The 2018 melting season
Post by: A-Team on March 21, 2018, 10:11:21 AM
I am just staking out a final piece of real estate here on the first page to hold more year-to-date summary time series at a stable location, as it looks like the 3 slots above and the 12 graphics may not be quite enough.

This area will hold synchronized cross-silo products, typically 4 of the ones above in a 2x2 array. This allows various parameters to be more easily compared when the same date is shown at the same time, however this comes at the cost of half-resolution.

The placeholder below shows Piomas thickness combined with Ascat roughness for the last 16 days of March. Combinations with sea surface temperature, DMI thickness, and SMOS ice thinness will be posted in a bit. Shorter time frames can be posted frame by frame as gifs whereas longer time series have to be presented as movies to keep file size reasonable. That unfortunately involves lossy compression whereas the gifs retain all the data (if it is 8-bit or less).
Title: Re: The 2018 melting season
Post by: Alexander555 on March 21, 2018, 10:30:38 AM
That area in the north-east of Greenland, looks like it's still open water.
Title: Re: The 2018 melting season
Post by: A-Team on March 21, 2018, 10:53:53 AM
Quote
north-east of Greenland, looks like it's still open water.
No, it froze over almost immediately and has stayed that way. While this follows from persistent cold air temperatures, the observational trick is to look for stable cracks ... these can only form when there is ice. DTU Sentinel-1AB cloud-penetrating radar is probably the best way to look at the area. WorldView has been beset with clouds over this particular spot that resemble open water visually; the VIIRS image below is from March 14th. That's no accident because very thin ice with rifts still transmits ocean heat and vapor effectively to the air leading to clouds. Ascat is somewhat fooled because the new ice is still very smooth (ie black shows lack of roughness) but open water is much more flashy because of weather-borne salinity.

http://www.seaice.dk/
https://www.polarview.aq/arctic
https://www.polarview.aq/images/105_S1jpgfull/S1B_EW_GRDM_1SDH_20180321T112507_4868_N_1.final.jpg

Early 3.125 km UH AMSR2 sea ice concentration showed a patch of 'blue' but here you have to get the file open in something like Gimp with a non-contiguous color picker to pull out the true zero concentration regions (of open water).

About two-thirds of the new polynya ice is already headed out the Fram export door. The GFS wind forecast has this continuing, whereas the other third will be driven west in the direction of the Nares and CAA. The ice volume involved is well-captured by the negative region in wipneus's graph below.
Title: Re: The 2018 melting season
Post by: Pmt111500 on March 21, 2018, 12:33:49 PM
Moving my premature comment from the earlier thread here. Most, if not everything in it is still valid  ;)

"Last year 2017 I was quite strongly in the belief we'd have a new absolute minimum in the amount of Arctic Sea Ice, in all measures. But instead, 2017 had an early melt in the Southern Ocean. Thus, no idea what happens on the Arctic during summer 2018. At least not yet. Hoping the NA drift is strong enough to keep the Greenland freezing temperatures out of Southern Finland better than last three years."

We've had a very cold March here, so relying on foreign news about AGW.
Title: Re: The 2018 melting season
Post by: Daniel B. on March 21, 2018, 01:46:14 PM
It has been a very cold March across much of the northern hemisphere.  How this affects Arctic sea ice this summer is unknown.
Title: Re: The 2018 melting season
Post by: VeliAlbertKallio on March 21, 2018, 03:47:03 PM
I doubt it affects much, we are still on some of the lowest volumes with fresh ice not having expelled as much salt as usual.
Title: Re: The 2018 melting season
Post by: oren on March 21, 2018, 04:03:19 PM
I think the first thing to expect of this melting season is an early melt-out of the Bering, and possibly record early inroads into the Chukchi.
Title: Re: The 2018 melting season
Post by: Gray-Wolf on March 21, 2018, 04:18:24 PM
Well I will certainly be looking at the number of high's that grace the basin this year esp. over the Atlantic side?
If low solar does lead to impacts in the propensity of HP's over the basin then maybe that would go some way to explaining why the record breaking years of 07', 2010, and 2012 were positioned where they were!

Last year we ha WACCy snow in west Siberia aiding with our protection of ice cover over the Atlantic side. This year we do not have that slow melting snow but are another year closer to solar Min.

It has been pretty clear on our side of the basin this last 3 weeks though?
Title: Re: The 2018 melting season
Post by: FishOutofWater on March 21, 2018, 04:52:12 PM
The polar vortex split / sudden stratospheric warming brought on a very cold March in the eastern U.S. and western Europe but the northern hemisphere is warmer than normal. We need to be careful to discern the difference between the cold weather where most of us live and the warm weather in the northern hemisphere.

Note that the CFS v2 climate model forecasts continued ridging and warmer than normal temperatures over the Aleutians, Alaska, and the Beaufort and Chukchi seas through July. It now forecasts a stormy August in the central Arctic. The CFS model tends to over-forecast warm anomalies so don't expect the magnitude of the warm anomalies to be accurate. Moreover, the CFS model doesn't handle ocean mixing well so don't trust it to be any good at all in areas where there might be ocean mixing. I have chosen to post the forecast 850mb temperatures rather than the 2m near surface temperatures because they are a reflection of atmospheric dynamics. I don't trust the CFS model to deal with the sea ice and ocean mixing issues that strongly affect near surface temperatures. With those caveats, the CFS v2 model forecasts posted below make good sense as a continuation of the weather and ocean heat patterns that have been developing over the past 2 months.

July's forecast of higher than normal pressure on the Alaskan side of the pole could melt out large volumes of sea ice on the Pacific side of the Arctic while continuing transport out of the Fram strait. We'll see how this all plays out in September but these forecasts would put this year in contention for a record low in September.
Title: Re: The 2018 melting season
Post by: bbr2314 on March 21, 2018, 05:57:19 PM
Anecdotally we already have 4" on the ground in the middle of the world's most prominent heat island directly on New York Harbor. Manhattan may see up to 12"+++ by the time the snow is finished in 18-24 hours. It is March 21st, and this has not happened since 1866.

This March has been unprecedented in terms of the practical WX in the NE US and I believe it is because we have temporarily reached a tipping point where dynamics favoring ice sheet expansion have now outweighed background heat, which is why NYC went from record warmest Feb to... this.

This relates back to the freezing season because I think it is directly related to what is happening in the Bering and Labrador/Baffin, where the ongoing flux from ice formation & destruction and the residual impact from albedo anomalies over the continents sufficient to create a near-standing atmospheric wave pattern.

We may see freak weather actually worsen into April, with snows maintained across populated regions as the current SWE anomalies show no signs of dropping just yet.

Again, relating back to the ice, the insane situation in the mid-latitudes should pump the Arctic full of heat transported from the ocean (...models are now showing the first major typhoon of the season as well). I think we are going to shortly see a dramatic opening of Bering + Chukchi and by 5/1 the front will be hundreds of miles more advanced than any other year in record-keeping. This will not be good for humans.

In good news, we may be at hemispheric SWE max? In bad news, if 1866 is not coincidental, it only takes about 40% more accumulated SWE vs. late 20th century normal to result in practical NHEM weather that mimics the end of the Little Ice Age. If another several years of ice decline lead to a continued increase in SWE, it isn't hard to imagine 1812-esque winters on the regular if we have already (possibly) regressed to the 1860s in terms of accumulated volume and are seeing the same weather as back then...

(...adding up possible coincidences, NYC's last period of five consecutive 30"+ winters was also in the 1860s, immediately when records started, unmatched since.... 2013-14 through today!)

(https://ccin.ca/home/sites/default/files/snow/snow_tracker/nh_swe.png)
Title: Re: The 2018 melting season
Post by: Archimid on March 21, 2018, 06:34:48 PM
This March has been unprecedented in terms of the practical WX in the NE US and I believe it is because we have temporarily reached a tipping point where dynamics favoring ice sheet expansion have now outweighed background heat, which is why NYC went from record warmest Feb to... this.

 I think your are right that some of these WACCy dynamics are what some ice sheet expansions probably looked like, but I disagree that's in any way a sign that snow dynamics have already outweighed the background heat. They might eventually, but it has to be much worse than this.
Title: Re: The 2018 melting season
Post by: bbr2314 on March 21, 2018, 06:46:26 PM
This March has been unprecedented in terms of the practical WX in the NE US and I believe it is because we have temporarily reached a tipping point where dynamics favoring ice sheet expansion have now outweighed background heat, which is why NYC went from record warmest Feb to... this.

 I think your are right that some of these WACCy dynamics are what some ice sheet expansions probably looked like, but I disagree that's in any way a sign that snow dynamics have already outweighed the background heat. They might eventually, but it has to be much worse than this.
Correction: the snow dynamics *currently* outweigh background heat, I think by May and June they will fail, so you are definitely right.

The question is how much worse it has to get before May/June are off the table. With such an apparently dramatic response to ice loss as-is, another 10-20% wintertime decline with a corresponding increase like we have already seen in SWE is possibly sufficient, at that point we could be talking about seasonal max approaching 6,000 KM^3 of SWE, or 2X ~yr2000 avg.

If the summertime sea ice trends hold, ^ is feasible (IMO) by 2025. By 2030, we could end up with a planet that looks substantially different from today.
Title: Re: The 2018 melting season
Post by: gerontocrat on March 21, 2018, 08:15:10 PM

If the summertime sea ice trends hold, ^ is feasible (IMO) by 2025. By 2030, we could end up with a planet that looks substantially different from today.

There is a thread entitled "Ice-free Arctic" where people argue passionately about their view of the future of sea-ice and the climate generally. It is fascinating.

But this is the 2018 Melting Season Thread. I come here to see the amazing stuff from A-team and many others on what is happening and its influence on the melting season. Evidence and discussion on the the impact this year of the very high snowfall in the northern hemisphere this winter and spring is obviously part of the content for this thread.

Horses for courses. Choose the place you are going to make your case and go for it. (I speak as one who was chided by the Guv'nor more than once)
Title: Re: The 2018 melting season
Post by: Neven on March 21, 2018, 08:54:18 PM
I agree. Actual snow cover is extremely interesting, but updates on what it means in the long(er) run need to be posted elsewhere.
Title: Re: The 2018 melting season
Post by: FishOutofWater on March 21, 2018, 09:03:46 PM
Judah Cohen has discussed how sudden stratospheric warmings are followed by 4 to 8 weeks cold stormy weather in the Northeast U.S. many times. You should read his blog.

https://www.aer.com/science-research/climate-weather/arctic-oscillation/

As far as the upcoming weather I am not sure that I have much profound to discuss.  We are coming to the end of the stratosphere-troposphere coupling season.  I do think that the coupling is still active and that the current stratospheric PV displacement with a weakened PV center over western Siberia is related to the low heights and cold temperatures across Siberia.  Counterclockwise flow around the low height center both in the stratosphere and its reflection in the troposphere is resulting in a cold easterly flow of air out of Siberia and into Europe.

Cold temperatures and the very active storm track in the Eastern US is harder to explain.  There is some weak ridging in the polar stratosphere centered in and around Alaska that has a tropospheric reflection.  This would favor downstream troughing across the Eastern US.   Cold and possibly snowy weather is consistent with our new study that warm PCHs overwhelmingly favor more wintry weather in the Eastern US.  In addition there is a recent study by Zhang et al. (2016) that a displaced stratospheric PV towards Eurasia favors cold temperatures in eastern North America.  I expect this overall pattern across the NH to linger and weaken over time right up until the Final Warming when the stratospheric PV  disappears for the reminder of the spring and the summer.

It is my impression that once we move beyond the month of March spring weather/conditions advance fairly aggressively across the NH.  This manifests in a what I would describe as a collapse in continental snow cover during April and May.  Snow cover is currently relatively extensive both across North America and Eurasia with widespread cold temperatures, especially across Northern Eurasia.  It will be interesting to see how quickly the continents warm-up and how quickly snow cover recedes in the coming weeks and if possibly this spring, snow cover can buck recent trends.  One region I expect to heat up quickly regardless is the Western US but even there snow cover is extensive and maybe I will be wrong.

and after a long discussion

Recent research has shown that regional anomalies are important and the sea ice region most highly correlated with the winter AO is the Barents-Kara Seas region where low Arctic sea ice favors a negative winter AO and a cold Eurasia. Current warm Arctic/cold Eurasia pattern is nearly textbook and has been linked previously to low sea ice extent in the Barents-Kara Seas.  Continued below normal sea ice in this region may have contributed to more active WAFz/poleward heat transport that resulted in a stratospheric PV disruption.
Title: Re: The 2018 melting season
Post by: romett1 on March 21, 2018, 09:07:54 PM
I think the first thing to expect of this melting season is an early melt-out of the Bering, and possibly record early inroads into the Chukchi.
How Bering Sea is ready for coming storms - here is sea ice area according to NSIDC on March 20 each year (2007 - 2018). I try to update the table over the next days - hope this is interesting to know.
Title: Re: The 2018 melting season
Post by: Alexander555 on March 21, 2018, 09:21:33 PM
In some way it's a little strange to see 2012 as the highest number, and it had the lowest minimum the same time. And for this year it's the lowest number. Can somebody tell something about that 2011/2012 winter ?
Title: Re: The 2018 melting season
Post by: numerobis on March 21, 2018, 09:52:09 PM
Seems the ice is acting up in Frobisher Bay an hour or two by snowmachine out of town. This is very early; it shouldn't be even much of a topic until mid to late May normally.

https://www.facebook.com/groups/iqaluitpublicservice/permalink/1682339141802056/
Quote
A hunter is warning people that some ice conditions are NOT safe out there especially Qairuliktuut area. It is different this year he says. Be very cautious and this is March.

Maps here. Warning: they're pretty, you might waste a lot of time reading them.
http://ihti.ca/eng/place-names/pn-seri.html
Title: Re: The 2018 melting season
Post by: subgeometer on March 21, 2018, 10:50:51 PM
This March has been unprecedented in terms of the practical WX in the NE US and I believe it is because we have temporarily reached a tipping point where dynamics favoring ice sheet expansion have now outweighed background heat, which is why NYC went from record warmest Feb to... this.

 I think your are right that some of these WACCy dynamics are what some ice sheet expansions probably looked like, but I disagree that's in any way a sign that snow dynamics have already outweighed the background heat. They might eventually, but it has to be much worse than this.

I have to agree. It can only be a superficial resemblance, given the warmth in the ocean and continental areas where snow doesn't fall or last on the ground. Heat transport eg in the form of rain can soon wipe out snow cover (as often happens in Australia in the Ice-age-glaciated Snowy mountains). The albedo of extra snow in spring and early summer makes a negative feedback but I can't see it outweighing the warming trend. Either way, we're in uncharted territory now
Title: Re: The 2018 melting season
Post by: FishOutofWater on March 21, 2018, 10:57:38 PM
Offshore winds have exported ice from the region of S Baffin island into the Labrador sea. Very stormy weather combined with intense blocking highs this winter has caused extensive mixing in the Labrador sea and that's put warm salty water in contact with ice on the margins of the open water of the Labrador sea. This situation may increase the rate of melting all the way into Hudson's bay because ice is moving through the passages.

Below is today's March 21, 2018 worldview Terra visible image showing open water and very thin ice around the south side of Baffin Island.

Note the above normal SSTs at the margins of the ice in the Labrador sea in yesterdays SST reanalysis map.
Title: Re: The 2018 melting season
Post by: Neven on March 21, 2018, 11:06:14 PM
It's Baffin and Barentsz that have heralded the max. Okhotsk is about to join the festivities:
Title: Re: The 2018 melting season
Post by: jdallen on March 21, 2018, 11:09:18 PM
In eastern Massachusetts, I've seen 30CM of snow disappear in 48 hours.

I al so know that snowfall across the northern boreal forest won't particularly reduce albedo, just slow the start of biological spring. Im not sure that extra snow on the tundra will last that much longer.

Snow on the ice is the thing as that kicks up the albedo and has a better chance of persisting, and is what has helped save the ice the last few years. Will it this time?
Title: Re: The 2018 melting season
Post by: A-Team on March 21, 2018, 11:21:02 PM
Ok, so who has a full set of actionable links to the best daily snow data sets?

I don't see a need for more generic bs about butterflies flapping their wings in the Amazon or snow cover of NH / land, sure it's all important but what we are looking for are snow depth maps at reasonable resolution, ie snow resting on Arctic Ocean sea ice as this is the AO melt season forum. In fact, better than canned maps is the netCDF data archive underlying the map, if we plan to compare approaches like we do with ice thickness.

Ok, so who has a full set of actionable links to the best daily AO albedo data sets?

Ok, so who has a full set of actionable links to the best daily AO melt pond data sets?

Ok, so who has a full set of actionable links to the best daily AO cloud data sets?
Title: Re: The 2018 melting season
Post by: oren on March 22, 2018, 01:32:01 AM
Correction: the snow dynamics *currently* outweigh background heat, I think by May and June they will fail, so you are definitely right.

The question is how much worse it has to get before May/June are off the table. With such an apparently dramatic response to ice loss as-is, another 10-20% wintertime decline with a corresponding increase like we have already seen in SWE is possibly sufficient, at that point we could be talking about seasonal max approaching 6,000 KM^3 of SWE, or 2X ~yr2000 avg.

If the summertime sea ice trends hold, ^ is feasible (IMO) by 2025. By 2030, we could end up with a planet that looks substantially different from today.
I would like to read your response to my analysis of Goose Bay snow dynamics history, in the thread I consider more appropriate for that discussion, NHEM snow cover.
https://forum.arctic-sea-ice.net/index.php/topic,103.msg146189.html#msg146189 (https://forum.arctic-sea-ice.net/index.php/topic,103.msg146189.html#msg146189)
Title: Re: The 2018 melting season
Post by: Iceismylife on March 22, 2018, 03:06:14 AM
...

I don't see a need for more generic bs about butterflies flapping their wings in the Amazon...
Then how about a scientific discussion about rainmaking?
Title: Re: The 2018 melting season
Post by: Archimid on March 22, 2018, 03:22:16 AM
Quote
Ok, so who has a full set of actionable links to the best daily AO albedo data sets?

I'm not sure this is what your asking for but I found this NASA sites that keeps Monthly Albedo maps and I think the data too.

https://neo.sci.gsfc.nasa.gov/view.php

Using images I got form that site I made the following animation. The animation is for March 2015-2016. The site seems to stop after February 2017.

Title: Re: The 2018 melting season
Post by: FishOutofWater on March 22, 2018, 03:59:05 AM
NOAA PSD's maproom has many useful maps including outgoing longwave radiation, but I'm not someone who downloads data and processes it myself. Here's where you can see many OLR maps:
https://www.esrl.noaa.gov/psd/map/clim/olr.shtml

Note the anomalous heat in the Barents sea. There's a lot of ocean heat near Svalbard that will start taking a toll on sea ice later this spring.
Title: Re: The 2018 melting season
Post by: jdallen on March 22, 2018, 06:22:20 AM
I'm wondering if we need to primarily non-US sources because of how NOAA has been slagged.  That said, I'd expect something like a gridded albedo map might slip under the Trump admin's radar and might be locate-able.
Title: Re: The 2018 melting season
Post by: jdallen on March 22, 2018, 06:29:18 AM
With daylight back, Worldview again moves up in the list of tools I use to watch what's going on.

So, to all of you, happy Equinox, and I give you a shot of the CAB just north of Svalbard, snagged from 3/21.

This area has been persistently open for most of a month, and the image I think gives us insight as to why.

The filament-like melting along the ice margin speaks to a very abrupt but significant temperature differential in the water.  This early, to see this, at this latitude I find very disturbing.

[Edit:  Checking Bathymetry, the region seems to correspond roughly to the edge of the Yermak Plateau, which leaves me wondering if its channeling warmer water from the Gulf Stream branch that is creating the hot spot just SE of Svalbard.]

[Edit2: Added Google Earth snip rotated to approximate the orientation from Worldview for comparison. I apologize for the relatively crude work.]

https://goo.gl/images/mrqB2b
Title: Re: The 2018 melting season
Post by: jdallen on March 22, 2018, 07:07:48 AM
Next montage - Western CAA including the Amundsen Gulf and the "uncorked" NW passage using worldview corrected reflectance bands 3-6-7.  Top is 2018, followed by 2017 on 3/22 and 2016 on the same date.  Banks Island is in the center of each frame.

I leave you to draw your own conclusions about comparative ice quality.
Title: Re: The 2018 melting season
Post by: Sterks on March 22, 2018, 02:17:53 PM
In eastern Massachusetts, I've seen 30CM of snow disappear in 48 hours.

I al so know that snowfall across the northern boreal forest won't particularly reduce albedo, just slow the start of biological spring. Im not sure that extra snow on the tundra will last that much longer.

Snow on the ice is the thing as that kicks up the albedo and has a better chance of persisting, and is what has helped save the ice the last few years. Will it this time?

I don't think it is snow on ice exclusively. Last year an excess 4 million km2 of snow cover on land had quite an effect. According to certain citizen-scientist models, something like an extra million km2 of ice in September.

Hey: 4 million km2 is about the surface area of the entire European Union (actionable link: https://en.wikipedia.org/wiki/Geography_of_the_European_Union). That's a lot of extra albedo persisting during the critical thawing months.

Hey: how is snow cover coming out of the Equinox? Colder than the climatology, but a lot can change from now till May.
Title: Re: The 2018 melting season
Post by: A-Team on March 22, 2018, 03:17:31 PM
I am not keen on reading six months of data-free speculation on what conditions prevail in the Arctic Ocean based on home-town weather.

Do we know of model and observational data sources that track daily albedo, melt pond formation (none yet), snow depth, liquid and ice water paths in clouds, rates of bottom ice melting, radiative heat fluxes etc? If so, which are the most reliable, how were they made and vetted, what are the links, how should we represent them as forum graphics?

Here is one source of both daily data and short-term forecasts but amongst our 1375 members we surely know of others:

ftp://ftp1.esrl.noaa.gov/RASM-ESRL/ModelOutput

Here is an integrated CryoSat2 resource for Feb 2018; the next release will be on April 3rd.

ftp://data.meereisportal.de/altim/sea_ice/product/north/cryosat2/cs2awi-v2.0/Latest/l3c_monthly/2018/

Thx to Fish for the link suggestion below -- I'll take a look though it may not be independent of the links above. Note by using second forum button in second icon row, you can display an image without downloading it.

Quote
NOAA PSD's maproom has many useful maps including outgoing longwave radiation, but I'm not someone who downloads data and processes it myself. Here's where you can see many OLR maps: https://www.esrl.noaa.gov/psd/map/clim/olr.shtml
Title: Re: The 2018 melting season
Post by: gerontocrat on March 22, 2018, 03:27:20 PM

I don't think it is snow on ice exclusively. Last year an excess 4 million km2 of snow cover on land had quite an effect. According to certain citizen-scientist models, something like an extra million km2 of ice in September.

Hey: 4 million km2 is about the surface area of the entire European Union (actionable link: https://en.wikipedia.org/wiki/Geography_of_the_European_Union). That's a lot of extra albedo persisting during the critical thawing months.

4 million km2 of excess snow cover.
persisting during the critical thawing months.
 
Where ? Exclusively on the treeless Russian Tundra and Canadian Barrens bordering the CAB? Or elsewhere as well?
For how long  ? Weeks? Months? Days? Presumably 4 million km2 of snow was not there one day and all gone the next?

There is a test bed for this - Hudson Bay. Shallow, low salinity, mostly landlocked with a continental climate, essentially a frozen inland lake for most of the year- (the Baltic is similar). If extra snow with greater longevity has the effect of significantly slowing sea ice melt, one should see it in the Bay. Last year we did not - the number of days with less than 5% of ice coverage went up.

But I can't find a simple multi-year snow analysis (extent by time) of that part of Canada to test any correlation. But this year may be another test?
Title: Re: The 2018 melting season
Post by: El Cid on March 22, 2018, 03:45:53 PM


I don't think it is snow on ice exclusively. Last year an excess 4 million km2 of snow cover on land had quite an effect.

There are 3 major zones where your map shows positive snow anomalies: 1) Central Europe 2 ) US North, NorthEast, 3) The middle of the Middle Kingdom

I don't know about the last one, but the snow in the first two will be gone in 1-2 weeks. I'm in Central Europe, and two days ago it was all white around us, but as the Sun came up and temps moved above freezing, half of it is gone by today, and the rest will be gone in the next two days...
Title: Re: The 2018 melting season
Post by: Gray-Wolf on March 22, 2018, 04:47:29 PM
This is an issue with the WACCy snows in that we get copious amounts but a lot of it to the south of regions normally seeing winter snow?

I've read reports on folk watching 30cm of snow go over a two day period as 'normal' temps return.

that is returning to 'normal' takes the snow but we will also see WAA continue to push north across regions bringing days above the norm and rapid melt?

Last low solar saw some pretty big heat domes establish across inner continental areas. If it was low solar that helped these situations maintain then we know we have 3 or 4 years of similar now in front of us coupled with the renewed spurt in background warming.

I have great concerns over the changes the next few years might bring us from a final destabilisation of the 'hillocks' across Yamal to our first blue Ocean events ( and the wrench that would stuff into N. Hemisphere circulation).

Our first test will be the melt ponding over the Atlantic side of the basin this year? If the last vestiges of 'northern blocking' over the Atlantic keep skies clear over Barentsz/Kara then we will see an uptick in melt ponding ( if Greenland's high joins in the fun and adds to a beaufort high then we might be looking more toward a 'perfect melt storm' synoptic setting up?)
Title: Re: The 2018 melting season
Post by: FishOutofWater on March 22, 2018, 05:10:14 PM
The heavy March snows in the western U.S. will tend to lessen the severity of heat domes that build up in the U.S. mid-continent region. When the mountains in the west dry out early in drought years dry heat can build up at the 10,000 foot level and above then drift over the mid-continent. The result can be absolutely brutal heat. These March snows will also tend to lessen wildfire intensity. That's good news for ice in Greenland that might be affected by soot.

The snow in the U.S. and Europe is good news but don't expect it to have much effect on the sea ice because it won't stick around for long. Sudden stratospheric warmings like the one in mid-February appear to be an effective way of cooling the atmosphere for a month or two, but the heat is already building up in central Asia. Expect a rapid warm up and faster than normal loss of snow cover in April and May.
Title: Re: The 2018 melting season
Post by: jdallen on March 22, 2018, 05:30:59 PM
Here is the thing ... yes there were positive anomalies, and yes sea ice didn't melt as much as we feared it could, but I think it is a serious mistake to treat the land Snow cover anomalies as causal.  Thermal transfer from air to ice is trivial compared to insolation and water.  Air temperature is buffered by water as well.

Albedo over the oceans. Water temperature. Those are the main factors.
Title: Re: The 2018 melting season
Post by: Dharma Rupa on March 22, 2018, 05:45:44 PM
I am not keen on reading six months of data-free speculation on what conditions prevail in the Arctic Ocean based on home-town weather.
I speculate based upon Four'easters here in Boston that the Gulf Stream has switched to hugging the coast and it is going to play havoc with the Greenland Ice Sheet.
Title: Re: The 2018 melting season
Post by: A-Team on March 22, 2018, 05:50:39 PM
Quote
havoc with the Greenland Ice Sheet.
The long-running Greenland melt forum is located elsewhere.

Quote
Here is the thing ... mistake to treat the land Snow cover anomalies as causal.  Thermal transfer from air to ice is trivial compared to insolation and water.  Albedo over the oceans. Water temperature. Those are the main factors.

Right. The snow pack over Arctic sea ice will be increasing to mid-calf thickness in the Chukchi but remains minimal overall according to RASM ESRL. We won't have a refresh on snow density until early April. Albedo and insolation effects can only kick in ocean-wide after the pole hole is gone on March 29th (Modis Terra can image the entire Arctic). There are no melt ponds at this point.
Title: Re: The 2018 melting season
Post by: Dharma Rupa on March 22, 2018, 06:01:42 PM
Quote
havoc with the Greenland Ice Sheet.
The long-running Greenland melt forum is located elsewhere.
I'm betting on this year.  Not so much Greenland, as the Gulf Stream.  That might even reduce the heat in the North Atlantic -- though I think there is enough heat to go around.

The Atlantic is changing -- and I don't buy into the theory that the overturning will stop.  Much more likely is for the warm water to pile up and force its way into the Arctic -- just as it has been doing.

Title: Re: The 2018 melting season
Post by: Daniel B. on March 22, 2018, 06:06:12 PM


I don't think it is snow on ice exclusively. Last year an excess 4 million km2 of snow cover on land had quite an effect.

There are 3 major zones where your map shows positive snow anomalies: 1) Central Europe 2 ) US North, NorthEast, 3) The middle of the Middle Kingdom

I don't know about the last one, but the snow in the first two will be gone in 1-2 weeks. I'm in Central Europe, and two days ago it was all white around us, but as the Sun came up and temps moved above freezing, half of it is gone by today, and the rest will be gone in the next two days...

I have not checked the weather for Central Europe in the next two days, but the U.S. north and northeast is expecting more snowfall. 
Title: Re: The 2018 melting season
Post by: A-Team on March 22, 2018, 06:22:21 PM
Hello newcomers: in years past, 'The 2018 melting season' has just been a short name for what was actually 'The 2018 Arctic Ocean sea ice melting season' forum, just like the freeze season forum. Note this forum sits in a sub-directory of the Arctic Sea Ice collection.

Do we need to open a separate forum this year called the 'The 2018 Arctic Ocean sea ice melting season'? Otherwise we are going to have thousands and thousands of off-topic posts here by September.

I for one have zero interest in home-baked opinions not accompanied by outside factual support.  Do you really know anything about Atlantic Water intrusion into the Svalbard region beyond what is already beautifully imaged and forecast at Mercator Ocean? Where could this knowledge possibly be coming from? 

It's not what you know (or pretend to know) but how you know it. Attach a link, an image, a journal DOI, cite your post-PhD oceanographic research, something ... otherwise go to one of over 1850 chat room forums to vent personal feelings about how climate change will play out.

People are certainly welcome to their own opinions but not to their own facts (or lack thereof).
Title: Re: The 2018 melting season
Post by: gerontocrat on March 22, 2018, 06:29:26 PM
Hello newcomers: in years past, 'The 2018 melting season' has just been a short name for what was actually 'The 2018 Arctic Ocean sea ice melting season' forum, just like the freeze season forum.

Do we need to open a separate forum this year called the 'The 2018 Arctic Ocean sea ice melting season'? Otherwise we are going to have thousands and thousands of off-topic posts by September.
We have threads called "Ice-Free Arctic", "Northern Hemisphere Snow Cover". I guess Neven may have to get out the snips. Having one's words of wisdom castrated is a painful experience.
Title: Re: The 2018 melting season
Post by: Neven on March 22, 2018, 06:35:16 PM
I think it's going great so far!

Have we talked about snow yet? No causation, but perhaps a correlation.  ;)
Title: Re: The 2018 melting season
Post by: Dharma Rupa on March 22, 2018, 07:37:40 PM
I think it's going great so far!

Have we talked about snow yet? No causation, but perhaps a correlation.  ;)
I've seen it mentioned somewhere, but I am having trouble finding the forest for all the trees.

Best argument I've seen so far is that snow on ice is meaningful while snow under trees is meaningless.
Title: Re: The 2018 melting season
Post by: bbr2314 on March 22, 2018, 08:01:54 PM
I think it's going great so far!

Have we talked about snow yet? No causation, but perhaps a correlation.  ;)
I've seen it mentioned somewhere, but I am having trouble finding the forest for all the trees.

Best argument I've seen so far is that snow on ice is meaningful while snow under trees is meaningless.

That argument is flat out wrong.

The albedo differential here is plain and enormous and will have enormous consequence for the ice to the NE. The heat pump activated in the NE NATL with continental cold pressing on the warmest Gulf Stream on record (and the coldest/snowiest eastern North America for the time period) is extremely significant.

How can you ignore the albedo impact when sun angle is now equivalent to mid-September? We are three months from solstice. "Trees" may be green but the impact is still extreme. Compare/click attached to animate.

The Gulf Stream has slowly wandered north until this winter, where it has now consumed the Gulf of Maine entirely with its backwash of warm eddies. This has also resulted in the recent evaporation of all the sea ice in St. Lawrence/near Newfoundland, as the accumulated oceanic heat has made its way into the atmosphere (the same reason it has been dumping snow on the seaboard).

Juicing the ocean has the effect of depositing vast amounts of snow across the mid-latitudes when extant snow is present, and thanks to the spiraling feedbacks of the situation in the high-latitudes, that is now happening. We should see continued retreat over the Bering the next few weeks as cyclone after cyclones hammers the heat differential between the Bering + Okhotsk into uniformity, taking out the Chukchi as collateral damage (and probably leaving Okhotsk extremely intact into the end of April, anomalously so).

The same should happen over the Greenland Sea, with the impact there being massive snowfalls + melt over Greenland + ice melt in Greenland Sea/Barents/Kara, and continued sustained ice growth (certainly volume if not extent) in Baffin.

I think the snow situation will act as an additional heat pump into the high Arctic in April and May. As we see most everything melt out on the continents by late June, we will still be left with a very cold and snowy Hudson Bay, which (IMO) may see its first MYI in the satellite record come September.

That also means that Canada will have a far more durable additional anchor against the incoming Hadley heat come solstice/July/August. With the bulwarks stacked on the North American side of the hemisphere and impressive heat raring its head already across much of central Asia despite (or due to?) the snowfall anomalies, I think the start of the melt season will progress as follows:

April:

Baffin, Okhotsk, and Kara maintain or see slight gains. Bering drops precipitously and is at 0 by the end of the month, with losses extending into Chukchi by 4/15 and consuming much of its icepack by the end. Beaufort is also vulnerable and is substantially open by 4/30. Greenland Sea + Barents are hammered by constant low pressure barrages and see slight drops despite large volume losses as export revs into high gear.

May:

Baffin, Okhotsk, and Kara begin to feel the wattage. Melt begins and is in full swing by the end of the month.

The losses of April result in a cyclonic cannon that worsens as May starts. The gradient results in mass ice loss in Barents, Chukchi, and Beaufort.

Paradoxically, we see hemispheric snow anomalies worsen in May due to the increase in available moisture for the high Arctic (I expect that discounting Okhotsk/etc, Arctic proper is lowest extent/volume on record by 5/1 and by leaps and bounds by 5/30). The start of melt in Okhotsk + Baffin should drive substantial snowfalls in peripheral regions that are still covered, as well, and I think we are going to be very surprised with what we see in Siberia, Quebec, and Scandinavia by the end of May.

I will not speak beyond the next 60-75 days for now (however wrong ^ is, is only likely to get worse as we get further out). But I think the key takeaways are that albedo imbalance is now driving a latitudinal/geographic *volume* imbalance in terms of annual ice formation. That is now manifesting in areas like Bering ahead of others, and the rollover impacts -- already severe -- are only going to get worse.

Finally, we must not let the mean #s distract from the actual situation. The relative extent "recovery" this month distorts a whole picture that is similar to 2012 in how a very substantial (or entire) % of the growth is going to melt out by end of yr regardless. The situation in the high Arctic is about to take a nosedive.
Title: Re: The 2018 melting season
Post by: jdallen on March 22, 2018, 09:19:22 PM
To help winnow down this topic to narrow its focus, I've created the additional topic, "2018 Melting Season - Predictions and Speculation.

https://forum.arctic-sea-ice.net/index.php/topic,2280.0.html
Title: Re: The 2018 melting season
Post by: FishOutofWater on March 22, 2018, 11:24:06 PM
The Gulf Stream has not wandered. The Gulf Stream front exists at a depth of 318m, about 1000 feet, as you can see from thie images below. Ocean heat has been building up in the north west Atlantic for the past 2 decades and it's affecting everything from east coast snow storms to Arctic sea ice.

Heat in the north Atlantic works its way up into the Arctic over multiple years. The 300m level down to 600, and in some areas, more meters is the Atlantic water layer in the Arctic. There's been a moderate push of warm Atlantic water deeper into the Arctic's east Siberian sea continental margin at 300m over the past year.
Title: Re: The 2018 melting season
Post by: A-Team on March 22, 2018, 11:35:40 PM
Quote
Have we talked about snow yet?
I looked at windytv which offers Arctic Ocean snow accumulation forecasts ten days out according to 9 km ECMWF. Snow accumulation might total a few cm depending on location (which is a lot more than we are expecting here in Tucson AZ at 91ºF/33ºC).

It is way too cold now for rain-on-snow but that is something we need to follow very closely, given what N-ICE2015 observed during the spring north of Svalbard. Lightning strikes too... there's an app for that; my neighbor up the road developed it! He complains though about the satellite, stationary orbit make angles bad already by Hawaii. However Alaska has its own resources in the Beaufort Sea area; lightning's made the news here before.

Quote
Winter snow conditions on Arctic sea ice north of Svalbard during the ...
onlinelibrary.wiley.com/doi/10.1002/2017JD026753/full
by I Merkouriadi - ‎Cited by 5

Oct 25, 2017 - Winter snow conditions on Arctic sea ice north of Svalbard during the Norwegian young sea ICE (N-ICE2015) expedition ...... Thus, it is likely that the ice lenses over SYI were the result of surface melting or rain on snow. Another possibility for the formation of these lenses is glazing at the snow surface, due ..
.
The small creatures
http://www.npolar.no/en/expedition-field/n-ice2015/blog/2015-06-23-small-creatures.html
Jun 23, 2015 - Thick ice and snow prevent sunlight from reaching the sea water, which is where the nutrients and the grazers are. Therefore, sea ice algae are usually found in higher concentrations at the bottom of the sea ice. However, during our observations on our home floes, during Leg 5 and 6, we have discovered ...

Snow depth is hard to measure
http://www.npolar.no/en/expedition-field/n-ice2015/blog/2015-06-01-measuring-snow-depth.html
Blog: N-ICE2015

Jun 1, 2015 - The amount of snow and when it falls is changing, and most climate predictions suggest that more snow will fall in the Arctic as the climate warms, but later in the winter. In a warmer Arctic this snow could be very important to the fate of the sea ice.
Title: Re: The 2018 melting season
Post by: Michael Hauber on March 23, 2018, 12:46:00 AM
Here is the thing ... yes there were positive anomalies, and yes sea ice didn't melt as much as we feared it could, but I think it is a serious mistake to treat the land Snow cover anomalies as causal.  Thermal transfer from air to ice is trivial compared to insolation and water.  Air temperature is buffered by water as well.


No thermal transfer from air to ice is important as per peer reviewed research (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015GL064373)
Title: Re: The 2018 melting season
Post by: jdallen on March 23, 2018, 01:56:29 AM
Here is the thing ... yes there were positive anomalies, and yes sea ice didn't melt as much as we feared it could, but I think it is a serious mistake to treat the land Snow cover anomalies as causal.  Thermal transfer from air to ice is trivial compared to insolation and water.  Air temperature is buffered by water as well.


No thermal transfer from air to ice is important as per peer reviewed research (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015GL064373)
Take aways from the article...

First off, you're talking about August, not spring. 

Second off, the transfer wasn't direct; the heat transfer triggered a series of feedbacks, much of which relied on heat *already present* in the water, and the rest by way of changes to downwelling or out-going long-wave radiation. 

[edit] Third off, this was applied to ice which was already heavily preconditioned, so it while the effect was dramatic, the actual total transfer of heat would not have had as dramatic a visual effect at a time earlier in the season with similar levels of insolation (Early May).

The total heat content of that air mass was no where near sufficient to produce all that melt.

The heat definitely lead to inversion conditions which facilitated the melt, but as I read it, the heavy lifting came from elsewhere.
Title: Re: The 2018 melting season
Post by: subgeometer on March 23, 2018, 04:14:22 AM
I am not keen on reading six months of data-free speculation on what conditions prevail in the Arctic Ocean based on home-town weather.
I speculate based upon Four'easters here in Boston that the Gulf Stream has switched to hugging the coast and it is going to play havoc with the Greenland Ice Sheet.

NOAAs sst anomaly maps indicate just that
Title: Re: The 2018 melting season
Post by: Feeltheburn on March 23, 2018, 04:44:17 AM
What will be the effect of the huge and well above average amount of fresh water that will pour into the Arctic in the next few months as the record snows melt? Does it push ice away from the coasts and reduce ice? Or does it compress ice and make it harder to melt? What about its dilution effect? Can it decrease salinity enough to statistically raise the melting point of arctic ocean water and slow the melting? I have been watching this blog and the data for several years, and one thing is certain--there is no stasis, low predictability, and every year behaves independently. Maybe this will be the year where the arctic ice sets a record low. However, if I were a betting man, I'd bet it will be an average to low melting year, with summer lows higher than the past few years.
Title: Re: The 2018 melting season
Post by: oren on March 23, 2018, 05:06:30 AM
Although I dislike going off-topic, since the issue has been raised again, here is another analysis of land snow, this time in Siberia, again showing increased snowfall resulting in no delay in spring melt-out.
https://forum.arctic-sea-ice.net/index.php/topic,103.msg147002.html#msg147002 (https://forum.arctic-sea-ice.net/index.php/topic,103.msg147002.html#msg147002)
Title: Re: The 2018 melting season
Post by: Michael Hauber on March 23, 2018, 07:06:26 AM

Take aways from the article...

First off, you're talking about August, not spring. 

Not relevant to the point of whether warm air from outside the Arctic can make a difference to the ice.  Warm air advection in summer can transfer enough heat into the arctic to melt a bunch of ice.  Warm air advection in spring will precondition the ice.  Warm air advection in winter will stop it growing as fast.


Second off, the transfer wasn't direct; the heat transfer triggered a series of feedbacks, much of which relied on heat *already present* in the water, and the rest by way of changes to downwelling or out-going long-wave radiation. 
...

The heat definitely lead to inversion conditions which facilitated the melt, but as I read it, the heavy lifting came from elsewhere.

Final sentence of article abstract

Quote
We argue that this rapid melt was triggered by the increased heat flux from the atmosphere due to the warm‐air advection.

feedbacks etc contributed, but it looks to me like direct heat flux due to warm air was the majority.  Regardless of whether indirect or direct, it was the warm air advection that triggered the melt, and so the impact of snow cover on albedo cannot be argued to be trivial as the atmosphere cannot carry enough heat to melt the ice.
Title: Re: The 2018 melting season
Post by: romett1 on March 23, 2018, 09:03:47 AM
Forecast for April 2 - haven't seen temperature anomalies like this for a long time. Of course it's far away, but current models show that new "heatwave" is starting to enter the Arctic from Pacific side somewhere around March 29. Image: http://cci-reanalyzer.org/
Title: Re: The 2018 melting season
Post by: Archimid on March 23, 2018, 02:35:02 PM
Polar SSTA's from 2015-2018
Title: Re: The 2018 melting season
Post by: FishOutofWater on March 23, 2018, 03:06:53 PM
The anomalous Gulf Stream heat has caused more intense snowstorms in the mid-Atlantic and northeast U.S. for 2 decades. If you look at the records of the heaviest snowstorm in the eastern U.S. you will see that it is weighted towards the last 2 decades. The excess Gulf Stream heat has also worked its way into the Arctic ocean in the Atlantic water layer. Excess ocean heat was one of the drivers in the loss of Arctic sea ice in the decade from 2001 through 2010. I have been following SST and ocean heat patterns since 1980 because I am interested in hurricane forecasting.
Title: Re: The 2018 melting season
Post by: bbr2314 on March 23, 2018, 03:08:58 PM
The anomalous Gulf Stream heat has caused more intense snowstorms in the mid-Atlantic and northeast U.S. for 2 decades. If you look at the records of the heaviest snowstorm in the eastern U.S. you will see that it is weighted towards the last 2 decades. The excess Gulf Stream heat has also worked its way into the Arctic ocean in the Atlantic water layer. Excess ocean heat was one of the drivers in the loss of Arctic sea ice in the decade from 2001 through 2010. I have been following SST and ocean heat patterns since 1980 because I am interested in hurricane forecasting.
You are correct, but this year is on steroids, and SSTA are higher than ever in Gulf of Main/off Nova Scotia, precisely because what you are describing has worsened substantially up to this winter.
Title: Re: The 2018 melting season
Post by: FishOutofWater on March 23, 2018, 05:03:24 PM
NOAA's map of global oceanic heat content goes through 31Dec2017. It shows the build up of heat in the western north Atlantic and the Atlantic side of the Arctic.

(https://data.nodc.noaa.gov/woa/DATA_ANALYSIS/3M_HEAT_CONTENT/FIGURES/3month_heat/hc_20172017_10-12.jpg)

We'll see how this heat affects the Arctic sea ice. It's already contributed to the low sea ice in the Labrador and Barents seas.

modification:
The figure isn't showing up for me now - don't know why - so it is posted below as an attachment>
Title: Re: The 2018 melting season
Post by: gerontocrat on March 23, 2018, 05:30:23 PM
What is more the increase in Global Ocean Heat Content in 2017 was a lot.
We are still in La Nina - so the next two quarters increases (Jan 1 to Jun 30) should be high.
But where will that additional heat go to?

Yet more uncertainty but pointing in the wrong direction for Arctic sea ice.
Title: Re: The 2018 melting season
Post by: FrostKing70 on March 23, 2018, 05:50:20 PM
A bit off topic (apologies!) but can anyone point me to a good site for the Gulf Stream and changes over time in the Gulf stream?
Title: Re: The 2018 melting season
Post by: romett1 on March 23, 2018, 06:08:18 PM
Update - Bering Sea ice area has dropped further 20,000 km² in two days (NSIDC). Table is reflecting values each year on March 22. Considering that Bering Sea remains stormy and relatively warm over the next few days, we should expect further declines there. Graph: https://sites.google.com/site/arctischepinguin/home/amsr2/grf
Title: Re: The 2018 melting season
Post by: FishOutofWater on March 23, 2018, 06:26:19 PM
The GFS model shows continued warm southerly winds clearing the sea ice out of the Bering sea over the next week or more. There's a dipole setting up in the Arctic ocean with low pressure on the Siberian side. This will not only hit the Bering sea, it will tend to export ice out of the Chukchi sea and pull Pacific water into the Chukchi through the Bering strait.

This is a rough start of the melting season for sea ice on the Pacific side of the Arctic ocean.
Title: Re: The 2018 melting season
Post by: jdallen on March 23, 2018, 06:57:08 PM
NOAA's map of global oceanic heat content goes through 31Dec2017. It shows the build up of heat in the western north Atlantic and the Atlantic side of the Arctic.

We'll see how this heat affects the Arctic sea ice. It's already contributed to the low sea ice in the Labrador and Barents seas.
We can see it now.  Here's the ice killing zone at the south end of Baffin Bay.
Title: Re: The 2018 melting season
Post by: jdallen on March 23, 2018, 07:04:57 PM
Same story, Fram strait.

There is an awful lot of heat ready to dump into the ice, and it's all heading north.
Title: Re: The 2018 melting season
Post by: Ken Feldman on March 23, 2018, 07:55:42 PM
A bit off topic (apologies!) but can anyone point me to a good site for the Gulf Stream and changes over time in the Gulf stream?

There's a good overview at carbon brief, link here:https://www.carbonbrief.org/the-atlantic-conveyor-belt-and-climate-10-years-of-the-rapid-project (https://www.carbonbrief.org/the-atlantic-conveyor-belt-and-climate-10-years-of-the-rapid-project)

Here's a link to the RAPID project, which measures the Atlantic current at 26N:  http://www.rapid.ac.uk/background.php (http://www.rapid.ac.uk/background.php)

Here's a picture from the site of the flows from the first decade of the Rapid project:

(https://www.carbonbrief.org/media/415339/screenshot-2015-06-19-183221_575x469.jpg)
Title: Re: The 2018 melting season
Post by: FrostKing70 on March 23, 2018, 09:13:19 PM
Thank you, good stuff!
Title: Re: The 2018 melting season
Post by: Neven on March 23, 2018, 11:02:24 PM
Short blog post on the ASIB: The 2018 melting season has started (http://neven1.typepad.com/blog/2018/03/the-2018-melting-season-has-started.html)
Title: Re: The 2018 melting season
Post by: jliukas on March 24, 2018, 12:15:39 AM
NSIDC have also released theirs: http://nsidc.org/arcticseaicenews/2018/03/arctic-sea-ice-maximum-second-lowest/
Title: Re: The 2018 melting season
Post by: NeilT on March 24, 2018, 01:36:44 AM
Talking about snow that triggered a memory about late season melting which desalinated the areas around the larger chunks of pack and slowed down the melting.  At least until a storm could come along and mix it up again.

That led me to search to see if there had been any study on the impact of large volumes of snow, melting on top of ice floes and what it does to the salinity.

I could only find this (https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2006JC003493) article which studies the landfast ice near barrow.

From the preamble

Quote
Landfast sea ice cores from two sites in Point Barrow, Alaska, extracted between 1999
and 2001, show a progressive desalination and a corresponding shape transition in the
salinity profile starting at snowmelt onset, around 1 June

Something to look at I suppose but there is very little study about it and therefore it's unlikely that we will be able to quantify it to any meaningful level this year.



Title: Re: The 2018 melting season
Post by: oren on March 24, 2018, 09:32:48 AM
Interestin. I think the melting ice also freshens its vicinity. That's another positive feedback of the ice becoming more mobile, it leaves its self-created sanctuary and thus melts faster.
Title: Re: The 2018 melting season
Post by: uniquorn on March 24, 2018, 01:14:00 PM
That didn't last long :-\

Worldview Bering Strait Mar16-23
Title: Re: The 2018 melting season
Post by: A-Team on March 24, 2018, 01:46:25 PM
I'll be putting up some of 2017's from today to June 1st. The AMSR2 UH sea ice concentration did not show too much action until towards the end of this period, whereas Ascat, which runs from Jan 1st to June 1st, shows a very different configuration from this year but also high ice mobility and Fram export though again minimal CW rotation.

The 2018 to Mar 23rd is quite different, 3rd mp4. The final mp4 shows 2017 picking up where 2018 leaves off (ie from Mar 24 on to June 1st), rather a disconnect as the 2017 has more extensive smooth (dark) first year ice and lacks the 1000 km long stringer of thick CAA ice in the Beaufort-Chukchi.

Technical note: The 2018-17 concatenate frames are co-processed identically whereas the mp4s for individual years were optimized separately, for global and local contrast. All operations are done on 32-bit implementations of Ascat grayscale which provides a slight improvement with enlargements, brightness adjustment and adaptive histogram equalization over the original 8-bit gifs.  To see dates, set the mp4 to loop and move mouse off slider.
Title: Re: The 2018 melting season
Post by: FishOutofWater on March 24, 2018, 03:10:51 PM
Comparing the apparent thickness on ASCAT for day 81, the clockwise rotation on the CAA coast is striking this year and the effects of anomalous southerly winds over Siberia into the Chukchi sea and ESS is evident. There is compaction caused by the convergence of the southerlies with the rotation caused by the Beaufort high, which has been displaced towards the pole by anomalous southerly winds over the Bering straight region.

All in all the ice looks like it is in slightly better shape now than this time last year, but it looks very vulnerable to warm weather on the Alaska side of the pole.
Title: Re: The 2018 melting season
Post by: A-Team on March 24, 2018, 03:46:07 PM
Quite right, Fish. This week's winds, as shown in 3 hour increments five days out on GFS nullschool, will have quite a run of unusual effects on sea ice motion and export out across the Svalbard-FJL-SZ Barents line.

The cloud streets continue as cold air blows off the ice over warm waters to the south. The VIIRS image also shows some very 'flaky' behavior of the ice edge, as there is nothing to oppose wind stress on the water side. These flaky regions on the infrared correspond to bluish regions of reduced sea ice concentration on AMRS UH 3.125 km.

https://forum.arctic-sea-ice.net/index.php/topic,2141.msg146630.html#msg146630

Historically the Fram has been #1 in net ice export to melting grounds, with the Nares, Barents line, CAA garlic press secondary and Bering Strait rather lagging. This year has been odd in that a lot of ice is passing across the Barents line (or not even reaching it), the Fram has been off and on, with the CAA about to import The Cork into the Beaufort.

Quite a bit of ice is moving out south through the Northwest Passage out Baffin Bay despite the current blockage at Louther Island. Once in Baffin Bay, some 637 km of ice drift to the south have happened, 7.8 km per day adds up.

This is where thermodynamic models (and trend lines) will get it wrong at the end game: runaway wind fetch, incredible ice mobility, and massive transport to intra-basin and external warm seas.

That where this expert commentary on the negative NAO gets interesting: there's some potential there for anticipating Arctic Ocean wind patterns and so export vulnurabilities during the critical late summer months:

https://www.theatlantic.com/science/archive/2018/03/why-are-there-suddenly-so-many-noreasters/556145/
Title: Re: The 2018 melting season
Post by: romett1 on March 24, 2018, 06:15:17 PM
That didn't last long :-\
Small update - Bering Sea ice area has dropped further 20,000 km² in just one day (NSIDC). Table is reflecting values each year on March 23. And interesting fact - according to NSIDC in 2012 current level (200,000 km²) was first reached on May 30. Graph: https://sites.google.com/site/arctischepinguin/home/amsr2/grf
Title: Re: The 2018 melting season
Post by: oren on March 24, 2018, 06:23:24 PM
Thanks for these updates romett. The Bering is going fast. I wonder, that gif seems to show some open water on the Chukchi side too.
Title: Re: The 2018 melting season
Post by: romett1 on March 24, 2018, 06:51:48 PM
Thanks for these updates romett. The Bering is going fast. I wonder, that gif seems to show some open water on the Chukchi side too.
Seems like winds have pushed ice away from the coast in three places.
Title: Re: The 2018 melting season
Post by: Shared Humanity on March 24, 2018, 07:08:56 PM
Katsebue Sound as well.
Title: Re: The 2018 melting season
Post by: FishOutofWater on March 24, 2018, 11:10:14 PM
Pacific sea surface temperature patterns were similar to this March in 2011 when Bering sea ice extent was also very low. La Niña tropical convection and trade wind patterns push ocean and atmospheric heat to the western Pacific. The jet stream takes a track that's displaced north and west as it tracks towards the dateline. This situation causes frequent southerly winds and warming in the Bering sea. This year, perhaps because of global warming, the sea ice is in the worst shape we've seen there.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.ospo.noaa.gov%2Fdata%2Fsst%2Fanomaly%2F2011%2Fanomnight.3.24.2011.gif&hash=5ba2b5d18821a870d67038c7575bbc6f)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.ospo.noaa.gov%2Fdata%2Fsst%2Fanomaly%2F2018%2Fanomnight.3.22.2018.gif&hash=e106ff9416946ded0bbe8b311a478d57)
Title: Re: The 2018 melting season
Post by: Jim Hunt on March 25, 2018, 10:17:45 AM
I see some SMOS thickness maps above, but lest we forget here's the latest visualisation of CryoSat-2 thickness as well:

http://GreatWhiteCon.info/2018/03/the-2018-maximum-arctic-sea-ice-extent/
Title: Re: The 2018 melting season
Post by: NeilT on March 25, 2018, 03:49:47 PM
I remembered that; whilst reading the blog of Tara Arctic during the IPY, I learned that project DAMOCLES output was used in the calibration of Cryosat-2.

I went looking for an article on DAMOCLES and found this article (https://www.researchgate.net/publication/315071784_Remote_sensing_of_sea_ice_advances_during_the_DAMOCLES_project).

It is highly informative about just how they go about producing the sea ice thickness maps they do and the role that snow, humidity and temperature play in it.

Extremely interesting was the fact that the type of snow plays a critical role in the albedo, with smaller, round, snow producing the higher albedo.  Meaning, to me, that a thinner snow cover may last longer and reflect more sunlight, than, says, 1M of very large flakes produced during a period of winter high temperature and humidity.  On top of that variability you have to add particulate matter, which highly impacts the end result.

It is quite clear from the article that sheer volume of snow, in itself, is not a great predictor of the eventual melting outcome.  Although, I would assume, 1M of snow will always produce more albedo than 1CM, regardless of the snow type.

It also highlights the criticality of knowing the snow/ice boundary, the temperature of the ice/sea interface and the wind speed and humidity over the ice.  All things measured by the Buoys which have been decreasing in number.

What we don't know about ice melt thermodynamics in the high Arctic would fill a book.  What we do know would fill a pamphlet.

Fortunately we do continue to learn.
Title: Re: The 2018 melting season
Post by: romett1 on March 25, 2018, 06:19:14 PM
Small update - Bering Sea ice area has dropped additional 22,000 km² in just one day (NSIDC). 2007 - 2017 average reached current level 53 days later on May 16.
Title: Re: The 2018 melting season
Post by: FishOutofWater on March 25, 2018, 06:47:28 PM
That's going to amount to a large amount of additional stored solar energy on the Pacific side. However, note that 2012 Bering sea ice extent was exceptionally high, yet we saw a record minimum Arctic ice extent in September.
Title: Re: The 2018 melting season
Post by: Gray-Wolf on March 25, 2018, 07:17:03 PM
That's going to amount to a large amount of additional stored solar energy on the Pacific side. However, note that 2012 Bering sea ice extent was exceptionally high, yet we saw a record minimum Arctic ice extent in September.

Which is why I worry of a link to HP dominance over low solar in the Basin? The HP that set up over Greenland in 2012 lead to the exceptional melt there ( even at summit!) and the pressure over the Atlantic side high melt early on in the season?

If the northern blocking that impacts NW Europe over low solar does indeed tend to drift north at the end of winter then we should expect a few years of clear skies over Barentsz/Kara/Greenland in early melt season?

We saw a terrible heat dome form over N Russia in 2010 ( leading to grain shortages there and wildfires across the Tundra) which also spilled into the ESS over that melt season?

With the year so far seeing over 50% spotless days on the Sun I will be watching the Atlantic side over these opening weeks of melt season?
Title: Re: The 2018 melting season
Post by: A-Team on March 25, 2018, 07:40:45 PM
Quote
JimH sees some SMOS thickness maps above, but lest we forget here's the latest visualisation of CryoSat-2 thickness as well
Jim, you might try comparing 30 day average to 30 day average. The Bremen palette is not suitable for that but you could grab the Hamburg daily netCDFs, open them all in Panoply set to their grayscale (or tinted gray) palette, save out the pngs, layer them up in Gimp and hit the average button. To compare, find the netCDF for the Cryosat and open that up too in Panoply to the same plot size and palette. To compare, just layer it up over the averaged Hamburg, hit grain extract and color differences by red and blue. However the issue is SMOS is best at thin ice (<1 m) and there's not much of that out there to compare with Cryosat.

Alternatively, for a rolling average comparison mp4 with daily update, use member Dryland's automation scripts, coming real soon at a DevCorner forum near you.

https://icdc.cen.uni-hamburg.de/thredds/catalog/ftpthredds/smos_sea_ice_thickness/v3/catalog.html

Quote
snow, fog, rain, Arctic atmospheric rivers
It's always a good idea to look at the follow-up to a given paper, here the 2016'er that M Hauber and jd have been discussing: just do a google search on the full title and click on the resulting cite count, then click through to count its references to first site. This one places the 2016 in a broader -- but very complicated -- context, 12 cites of it.

Note we went around and around on this on the Greenland forum last year, eventually learning it's not about the rain, it's the water vapor (humidity) associated with the rain, its better penetration into snow and ensuing in situ heat release from two rounds of condensation.

Quote
Poleward upgliding Siberian atmospheric rivers over sea ice heat up Arctic upper air
KK Komatsu et al Scientific Report (2018)
https://www.nature.com/articles/s41598-018-21159-6 free full

We carried out upper air measurements with radiosondes during the summer over the Arctic Ocean from an icebreaker moving poleward from an ice-free region, through the ice edge, and into a region of thick ice. Rapid warming of the Arctic is a significant environmental issue that occurs not only at the surface but also throughout the troposphere.

In addition to the widely accepted mechanisms responsible for the increase of tropospheric warming during the summer over the Arctic, we showed a new potential contributing process to the increase, based on our direct observations and supporting numerical simulations and statistical analyses using a long-term reanalysis dataset. We refer to this new process as “Siberian Atmospheric Rivers (SARs)”.

Poleward upglides of SARs over cold air domes overlying sea ice provide the upper atmosphere with extra heat via condensation of water vapour. This heating drives increased buoyancy and further strengthens the ascent and heating of the mid-troposphere. This process requires the combination of SARs and sea ice as a land-ocean-atmosphere system, the implication being that large-scale heat and moisture transport from the lower latitudes can remotely amplify the warming of the Arctic troposphere in the summer.
Title: Re: The 2018 melting season
Post by: Alexander555 on March 25, 2018, 07:48:16 PM
That's going to amount to a large amount of additional stored solar energy on the Pacific side. However, note that 2012 Bering sea ice extent was exceptionally high, yet we saw a record minimum Arctic ice extent in September.

Maybe there was a vortex collaps over the Bering sea in the 2011/2012 winter. For this winter i remember some chameleons falling out of trees in Florida.  Both represent  a big loss of cold in the arctic.
Title: Re: The 2018 melting season
Post by: bbr2314 on March 25, 2018, 09:33:00 PM
If long-range modeling is correct it seems like North America and Europe/NW Russia will be quite cold continentally while heat blasts the ice pack through D10. Both Canadian and EURO are especially consistent on keeping the PV over Hudson Bay and drenching Canada/the northern US in frigid Arctic air.

Combined with the stagnant pattern over Europe and the transience over Eurasia (due to heat belching north from the Sahara/Indian), I think this primes the mid-latitudes for major cyclonic activity as we continue through April, with warmest-ever SSTAs fueling major heat plumes that will enter directly into the Bering, Chukchi, Beaufort, as well as the Atlantic front/Russian seas on a less sustained but nevertheless substantial basis.

(https://www.tropicaltidbits.com/analysis/models/gem/2018032512/gem_T2ma_namer_41.png)

(https://www.tropicaltidbits.com/analysis/models/ecmwf/2018032512/ecmwf_T850a_nhem_10.png)

Over the next week I anticipate we see the melt front in the Bering begin to retreat, rapidly in some areas. This will accelerate as the sun rises higher in the sky, and by 4/10 I think we could see open water into Chukchi.
Title: Re: The 2018 melting season
Post by: Tor Bejnar on March 25, 2018, 10:22:42 PM
Some area decline already showing in Chukchi Sea, per ASIG regional SIA graphs - doesn't show on SIE graphs yet.
Title: Re: The 2018 melting season
Post by: Ice Shieldz on March 25, 2018, 11:36:44 PM
This kind of sea ice movement away from the the Alaskan/Canadian coast (and related ice fracturing) looks to continue over the next few days and perhaps longer.
Title: Re: The 2018 melting season
Post by: Jim Hunt on March 26, 2018, 12:20:04 AM
Jim, you might try comparing 30 day average to 30 day average.

Thanks for the tip on how to go about doing that.

Quote
However the issue is SMOS is best at thin ice (<1 m) and there's not much of that out there to compare with Cryosat.

However, as you point out, my point was not to compare two 30 day averages but rather to highlight the fact that SMOS lumps all "thick ice" into one rather large bin, and there's quite a lot of it about at this time of year.
Title: Re: The 2018 melting season
Post by: A-Team on March 26, 2018, 02:33:34 AM
There are two distinct SMOS products. The UH one is able to go out to slightly thicker ice (though the error grows) than the UB which is restricted to ≤0.5 m ice. There are efforts to integrate its relative strengths with those of CryoSat (which is nice by obviates comparison). The interest this time of year is anticipating opening of seas peripheral to the central ice pack.
Title: Re: The 2018 melting season
Post by: Shared Humanity on March 26, 2018, 03:50:27 AM
If long-range modeling is correct it seems like North America and Europe/NW Russia will be quite cold continentally while heat blasts the ice pack through D10. Both Canadian and EURO are especially consistent on keeping the PV over Hudson Bay and drenching Canada/the northern US in frigid Arctic air.

Combined with the stagnant pattern over Europe and the transience over Eurasia (due to heat belching north from the Sahara/Indian), I think this primes the mid-latitudes for major cyclonic activity as we continue through April, with warmest-ever SSTAs fueling major heat plumes that will enter directly into the Bering, Chukchi, Beaufort, as well as the Atlantic front/Russian seas on a less sustained but nevertheless substantial basis.

Over the next week I anticipate we see the melt front in the Bering begin to retreat, rapidly in some areas. This will accelerate as the sun rises higher in the sky, and by 4/10 I think we could see open water into Chukchi.

Thank you for this forward looking analysis. I wonder how this will play out and whether we can expect the Atlantic and Pacific pincers of heat intrusions that plagued the Arctic for much of the winter will continue through the melting season. I also would like to thank you for your restraint and limiting your forecast to just 2 weeks.  ;)
Title: Re: The 2018 melting season
Post by: oren on March 26, 2018, 04:13:16 AM
Hi, would someone please point me to where I can find an updated current version of this ASIV  piomass graph by Jim Pettit?

https://forum.arctic-sea-ice.net/index.php/topic,119.msg63605/topicseen.html#msg63605

any heads up about usefulness background would be appreciated. thx
Check out the amazing Pettit Climate Graphs, it's in there along with lots of other stuff.
https://sites.google.com/view/pettitclimategraphs (https://sites.google.com/view/pettitclimategraphs)
For a discussion of all things PIOMAS, check out the very long thread on this forum.
https://forum.arctic-sea-ice.net/index.php/topic,119.0.html (https://forum.arctic-sea-ice.net/index.php/topic,119.0.html)
Title: Re: The 2018 melting season
Post by: bbr2314 on March 26, 2018, 04:15:42 AM
If long-range modeling is correct it seems like North America and Europe/NW Russia will be quite cold continentally while heat blasts the ice pack through D10. Both Canadian and EURO are especially consistent on keeping the PV over Hudson Bay and drenching Canada/the northern US in frigid Arctic air.

Combined with the stagnant pattern over Europe and the transience over Eurasia (due to heat belching north from the Sahara/Indian), I think this primes the mid-latitudes for major cyclonic activity as we continue through April, with warmest-ever SSTAs fueling major heat plumes that will enter directly into the Bering, Chukchi, Beaufort, as well as the Atlantic front/Russian seas on a less sustained but nevertheless substantial basis.

Over the next week I anticipate we see the melt front in the Bering begin to retreat, rapidly in some areas. This will accelerate as the sun rises higher in the sky, and by 4/10 I think we could see open water into Chukchi.

Thank you for this forward looking analysis. I wonder how this will play out and whether we can expect the Atlantic and Pacific pincers of heat intrusions that plagued the Arctic for much of the winter will continue through the melting season. I also would like to thank you for your restraint and limiting your forecast to just 2 weeks.  ;)

:)

Satellite imagery already shows open water in Chukchi and massive crackage spreading into Beaufort and CAB as the Bering is seemingly giving out. With additional heat expected to spike significantly by D4 and continue unabated through D10+ on modeling, perhaps Chukchi could follow even sooner than thought.

It is interesting to see the direction of the fracturing now occuring. Rolling HYCOM in 2017 you can see how the gyre transported massive amounts of Pacific/Siberian ice toward the ATL. This is now occurring in full force.

The problem 2018 is going to face vs 2017 is that the amount of heat in the Pacific sector is going to be unprecedented. This means ice formation in Beaufort and Chukchi is going to be severely truncated vs. normal and even vs. last year.

The net result should be a volume shift toward the ATL side as we see open water advance rapidly into both Chukchi and Beaufort, driven by the advancing melt front *and* by the volume export toward the Atlantic. We may see an even worse version of 2012's fake spring #s occur, where the volume push toward the ATL inflates the amount of ice in the killing zone, countering the worst-ever losses (by a decent margin) in the Pacific.
Title: Re: The 2018 melting season
Post by: JayW on March 26, 2018, 12:27:41 PM
76 hour loop Chukchi and Beaufort regions, ending 0z March 26, 2018

http://feeder.gina.alaska.edu/npp-gina-alaska-truecolor-images?page=2&search%5Bfeeds%5D%5B5%5D=1&search%5Bsensors%5D%5B3%5D=1
Title: Re: The 2018 melting season
Post by: A-Team on March 26, 2018, 01:20:48 PM
The four time series below look at DMI sea ice surface temperature from Jan 1st to Mar 24th from the perspective of various palettes (the original is hue-only, constant saturation and value can be discarded). The Chukchi and Svalbard regions are quite a bit warmer than the central Arctic as is the thin new ice that appeared NE of Greenland after the late February storm. The resolution of ice fractures is quite good when it shows through but Ascat remains better for feature tracking.

It appears they had limited success in removing the clouds (despite recent persistent high pressure) but nonetheless describe the product as follows:

Quote
The figure shows the mean temperature of the sea ice and the surface of the sea based on satellite observations during the past 36 hours.

The surface temperature of the ice has a great influence on the exchange of heat between the surface and the atmosphere, and thereby also the rate of increase of the sea ice volume.

Data from satellites is the primary source of information because the Arctic suffers from poor coverage in terms of the conventional observational network, which consists of drifting buoys and a number of land-based stations.

At DMI, the temperature of the surface is not measured directly. Instead, observations are used from three infrared channels on the “Advanced Very High Resolution Radiometer” (AVHRR), which is on board the MetOp-A satellite. The instrument is unable to see through clouds, however. A statistical method is therefore used to provide the missing data. The edge of the ice is shown as a black contour line. It is defined by a sea ice concentration of 15%, i.e. 15% of the surface is covered by ice.

http://polarportal.dk/en/sea-ice-and-icebergs/sea-ice-temperature.
Title: Re: The 2018 melting season
Post by: Jim Hunt on March 26, 2018, 02:47:50 PM
A heads up for followers of the Norwegian young sea ICE (N-ICE2015) expedition:

http://GreatWhiteCon.info/2016/12/arctic-sea-ice-news-from-agu/

The N-ICE2015 special issue in the Journal of Geophysical Research is now complete, and has moved to a new URL:

https://agupubs.onlinelibrary.wiley.com/doi/toc/10.1002/(ISSN)2169-9291.NICE1

Several of the papers are open access.
Title: Re: The 2018 melting season
Post by: A-Team on March 26, 2018, 03:57:15 PM
Quote
Several of the papers are open access.
Believe they all are, just search 'Researchgate + full title'

Here is the 83-day averaged temperature of the sea ice surface since Jan 1st according to DMI's Polar Portal series. The blue and white areas will have the thinnest ice as the top surface has been the warmest and will presumably be first to open up.

Indeed in the latest March 24th UH SMOS, thinness (salinity dielectric radar) correlates quite well with mean sea surface temperature (infra-red based, different satellite). However large very recent detachment of land-based ice in the Laptev and Kara cannot be expected to show up yet in averaged SST. Remarkably, the bottom of the M'Clure Strait cork is shown as whitish warm.

SMOS_Icethickness_v3.1_north_20180324.nc

Technical note: Making this summary statistic into a rolling average is moderately involved. The 83 pngs are imported and montaged, then color-separated as HSV with S and V channels discarded. The averaged image is then redisplayed with the 'union jack' indexed color table in ImageJ because of the central white and traditional blues and reds for heat (though it worked better reversed here). The grayscale palette is simultaneously recolored because it is embedded in the image. The original spectral palette with the numerical temperature scale is then put back in. Given a rolling window width, the process is then repeated on concatenated staggered layers in Gimp that are cut from ImageJ duplicates and averaged over the selected time span.
Title: Re: The 2018 melting season
Post by: romett1 on March 26, 2018, 07:01:54 PM

Satellite imagery already shows open water in Chukchi and massive crackage spreading into Beaufort and CAB as the Bering is seemingly giving out. With additional heat expected to spike significantly by D4 and continue unabated through D10+ on modeling, perhaps Chukchi could follow even sooner than thought.
Small update - Bering Sea ice area has dropped additional 21,000 km² in just one day (NSIDC). 2007 - 2017 average reached current level 54 days later on May 18. Looking at earth.nullschool we can see southern warm winds dominating between Thursday and Saturday. These winds could start biting Chukchi Sea again. Image: https://sites.google.com/site/arctischepinguin/home/amsr2/grf
Title: Re: The 2018 melting season
Post by: Alexander555 on March 26, 2018, 07:20:58 PM
And there want be much cold before saturday.
Title: Re: The 2018 melting season
Post by: bbr2314 on March 26, 2018, 07:42:11 PM
At least North American/NW Eurasian snow-water-equivalent will keep on rising...?

(https://www.tropicaltidbits.com/analysis/models/gem/2018032612/gem_z500aNorm_nhem_41.png)

(https://www.tropicaltidbits.com/analysis/models/gfs/2018032612/gfs_z500aNorm_nhem_41.png)

The heatwave expected to begin across Bering by D3-4 is now appearing increasingly severe across all guidance...

I think the below 2M T map does a good job of showing what we can expect heading deeper into spring, as well -- retention/volume building in parts of the CAB, volume pushing into ATL, and devastation across everything near the Pacific.

(https://www.tropicaltidbits.com/analysis/models/gem/2018032612/gem_T2m_nhem_24.png)
Title: Re: The 2018 melting season
Post by: Lord M Vader on March 26, 2018, 07:47:49 PM
While I don't think we'll see a new record low this year I think we need to watch how much heat that will be stored in Berings and Chukchi Sea this melting season. Might have a huge impact for the upcoming freezing season.
Title: Re: The 2018 melting season
Post by: magnamentis on March 26, 2018, 08:01:51 PM
While I don't think we'll see a new record low this year I think we need to watch how much heat that will be stored in Berings and Chukchi Sea this melting season. Might have a huge impact for the upcoming freezing season.

while i totally agree i strongly believe that sooner or later the ever poorer winters (du to the mentioned impact on freezing)will lead us to new lows no matter if the melting conditions will be extremely against the ice. even protected places and even though there is some positive feedback that is balancing things for a while, one day the system will have to give in to an ever more hostile (for the ice) environment all over the places which is why i (as usual) expect new record lows as being possible any year and more and more despite any locally ice friendly conditions.

as it has been each year now it will be very interesting and a lot is possible whle nothing is certain, not even a range is certain. after all we've been in for surprises again and again.
Title: Re: The 2018 melting season
Post by: Alexander555 on March 26, 2018, 08:05:18 PM
On the other side of the Bering Sea it all looks pretty cracked.
Title: Re: The 2018 melting season
Post by: Archimid on March 26, 2018, 10:05:14 PM
While I don't think we'll see a new record low this year I think we need to watch how much heat that will be stored in Berings and Chukchi Sea this melting season. Might have a huge impact for the upcoming freezing season.

Dropping this here for anyone that wants to follow that.
 
(https://drive.google.com/uc?id=0B1HTR0ONiUmEWHI4VkN1WDdpV3M&export=download)
Title: Re: The 2018 melting season
Post by: subgeometer on March 26, 2018, 10:30:48 PM
Remaining ice in the Bering Sea won't last long given the warm southerlies forecast for the next little while, its melting fast - here is the Bering Strait from 25 march on Worldview. It doesn't bode well for the Chukchi Sea.
Title: Re: The 2018 melting season
Post by: Shared Humanity on March 26, 2018, 11:51:59 PM
On the other side of the Bering Sea it all looks pretty cracked.

Ice will always appear fractured as it moves along the coast of Greenland. More interesting to me is the obvious signs of melt along the ice edge.
Title: Re: The 2018 melting season
Post by: be cause on March 27, 2018, 02:30:03 AM
Not sure about Greenland's relevance .. but Chuckchi looks like a week of southerlies will leave it a ragged mess . The ice may not wait around for melt ponds ... b.c.
Title: Re: The 2018 melting season
Post by: jdallen on March 27, 2018, 06:06:16 AM
As I anticipated, the Bering and Chukchi are just coming apart.

It looks to be about 3-4 weeks ahead of 2017, which was far from good.
Title: Re: The 2018 melting season
Post by: A-Team on March 27, 2018, 01:47:30 PM
Quote
Chukchi looks like a week of southerlies will leave it a ragged mess . The ice may not wait around for melt ponds
Here is the 7-day rolling average of the sea ice surface temperature, DMI polarPortal since 01 Jan 18. The Chukchi did not experience conditions conducive to thickening this winter, along with other peripheral seas with the exception of the Laptev.

The weather forecast by GFS nullschool is incredibly stable over the next 40 frames (five days), with winds sweeping the CAA icepack towards the Fram and Svalbard; a representative scene is shown below. Already, the long tongue of Kara ice intruded north of FJL is being stretched apart and the top of the M'Clure ice cork is shearing off to the west.

The Bering-Chukchi have been difficult for satellites to image, what with frequent storms sweeping in with clouds and only rare coverage by Sentinel-1AB (but central Chukchi today to Herald Island, Bering Strait on April 10th). The ice, all late FYI, hasn't formed stable features and ice movement has been fairly chaotic, with only occasional sense of ice exchange across the strait. The mp4 below shows the last 92 days.

https://www.polarview.aq/images/105_S1jpgfull/S1B_EW_GRDM_1SDH_20180326T181252_26F5_N_1.final.jpg
Title: Re: The 2018 melting season
Post by: Neven on March 27, 2018, 04:28:29 PM
I've posted a blog post on the ASIB describing the situation in the Bering (and Chukchi) Sea: Bering goes extreme (http://neven1.typepad.com/blog/2018/03/bering-goes-extreme.html)

Here are a couple of images/animations I've created for it:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fneven1.typepad.com%2F.a%2F6a0133f03a1e37970b01b8d2e5c4c1970c-800wi&hash=9776e6f581b7da93031514e3b08a6329)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fneven1.typepad.com%2F.a%2F6a0133f03a1e37970b01b8d2e5e789970c-800wi&hash=33ad3e93722f8151ce8b1c3e8f524e88)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fneven1.typepad.com%2F.a%2F6a0133f03a1e37970b01bb09fedefc970d-800wi&hash=91b2a5a40877da443cc0b7080db1d1a4)
Title: Re: The 2018 melting season
Post by: oren on March 27, 2018, 05:17:05 PM
I've posted a blog post on the ASIB describing the situation in the Bering (and Chukchi) Sea: Bering goes extreme (http://neven1.typepad.com/blog/2018/03/bering-goes-extreme.html)
Thank you Neven. The Bering situation is truly amazing.
Title: Re: The 2018 melting season
Post by: Lord M Vader on March 27, 2018, 06:15:48 PM
Thx Neven! :) Yes, the situation in the Berings Sea is truly unprecedented but the most concerning point is, which I wrote in my earlier post, whether this will mean a new state for the Arctic sea ice or if the upcoming freezing seasons will be more "normal". The lack of sea ice in Berings Sea mean that a huge amount of solar heat will be able to be stored there during this melting season which will make it even harder for the ice to form by next season.

Back in 1996 there was also very little ice in Berings Sea at this time of year even if 2018 is far lower compared to 1996. That melting season was however one of the coldest that have been seen.
Title: Re: The 2018 melting season
Post by: romett1 on March 27, 2018, 06:51:55 PM
Thank you Neven for the update. Small update - Bering Sea ice area has dropped additional 20,000 km² in just one day (NSIDC). 2007 - 2017 average reached current level 55 days later on May 20. I'm afraid that at some point I have to focus on Chukchi Sea ice area instead.
Title: Re: The 2018 melting season
Post by: Neven on March 27, 2018, 08:31:58 PM
Thanks, romett1, I've posted your table on the ASIB. And you inspired me to download all the data for March since 1979, calculate the average and make a bar graph (below). Mind you, there's still five days of data left for this year's March, and so the average will go down some more.
Title: Re: The 2018 melting season
Post by: Tor Bejnar on March 27, 2018, 08:34:16 PM
Further to romett1's "at some point ... focus [on] Chukchi"
Current ASIG (https://sites.google.com/site/arcticseaicegraphs/regional) extent graph for Chukchi Sea shows the beginning of a decline.
Title: Re: The 2018 melting season
Post by: Neven on March 27, 2018, 08:37:16 PM
PS Romett1, it says 138,839 km3 for March 26 2018 in your table. But in the data I've just downloaded from Wipneus it says 130,054 km2 for March 26 2018. I don't work with this data very often, and there are many different files on Wipneus' website, so maybe I did something wrong. I've used the nsidc_arc_nt_detail.txt file.
Title: Re: The 2018 melting season
Post by: romett1 on March 27, 2018, 09:04:12 PM
PS Romett1, it says 138,839 km3 for March 26 2018 in your table. But in the data I've just downloaded from Wipneus it says 130,054 km2 for March 26 2018. I don't work with this data very often, and there are many different files on Wipneus' website, so maybe I did something wrong. I've used the nsidc_arc_nt_detail.txt file.
I had a quick look, this explains - excel workbook contains average daily sea ice extent and area, using 5-day trailing averages. Link is here: https://nsidc.org/arcticseaicenews/sea-ice-tools/. Also I attached pdf file - page 8 for information. So if there is huge drop in one day, it takes some days to fully appear in numbers.
Title: Re: The 2018 melting season
Post by: Neven on March 27, 2018, 09:11:12 PM
Ah yes, the 5-day average! Of course, that makes perfect sense. Thanks, romett1.
Title: Re: The 2018 melting season
Post by: oren on March 27, 2018, 10:09:24 PM
Further to romett1's "at some point ... focus [on] Chukchi"
Current ASIG (https://sites.google.com/site/arcticseaicegraphs/regional) extent graph for Chukchi Sea shows the beginning of a decline.
Area graph shows it even better.
Title: Re: The 2018 melting season
Post by: Dharma Rupa on March 27, 2018, 10:34:35 PM
Further to romett1's "at some point ... focus [on] Chukchi"
Current ASIG (https://sites.google.com/site/arcticseaicegraphs/regional) extent graph for Chukchi Sea shows the beginning of a decline.
Area graph shows it even better.

I'm whistling past the blueyard (graveyard).
Title: Re: The 2018 melting season
Post by: uniquorn on March 28, 2018, 02:18:00 AM
As Bones would say, "it's transpolar drift Jim, but not as we know it...."
Title: Re: The 2018 melting season
Post by: SteveMDFP on March 28, 2018, 02:21:45 AM
As Bones would say, "it's transpolar drift Jim, but not as we know it...."

"Dammit, Jim, I'm a doctor, not a polar bear!"
Title: Re: The 2018 melting season
Post by: A-Team on March 28, 2018, 03:30:52 AM
As Bones would say, "it's transpolar drift Jim, but not as we know it...."
 
Not so fast, guys:

Quote
Admiral Leonard H. McCoy, MD (?) was a Human Starfleet officer of the 23rd and 24th centuries. He was an accomplished surgeon, physician, psychologist, and exobiologist. As chief medical officer, he served aboard the USS Enterprise for twenty-seven years.

McCoy's graduation from medical school was never confirmed by Star Trek but with four years of pre-med followed by four years of medical school, McCoy would normally have received his medical degree in 2253.
A good thing to do here, since the AO and NAO give a statistically significant but nonetheless pathetic first EOFs of 23% variance for DJFM plus use dated baseline from an unfamiliar planet, is run a classifier on OSI-SAF daily ice movement pngs.

It's not so much the MSLP nor the wind that interest us this time of year but the response of the ice -- whether it fits the elusively defined (do any two depictions look the same?) concept of TransPolar Drift. (Transpolar means across the pole Wrangel to Svalbard, circumpolar means around CW zonally, neither means neither.)

You won't find 20% of individual DJFM days remotely consistent with classical TPD. But the real bottom line is the time integral of daily drift -- and near total lack of TPD over the last twelve months -- which I have posted 30-40 times up-forum to no apparent effect.

http://osisaf.met.no/p/osisaf_hlprod_qlook.php?year=2018&month=02&day=26&prod=LR-Drift&area=NH&size=100%25
Title: Re: The 2018 melting season
Post by: uniquorn on March 28, 2018, 01:36:05 PM
Quote
which I have posted 30-40 times up-forum to no apparent effect

I couldn't resist a bit of humour and gained some ST lore.

Nonetheless, looking at the ascat sea ice roughness 01 Jan to 25 Mar 2018 above, accepting that the ice movement is largely rotational clockwise, there is a discernible export across the whole Atlantic front while losing ice cover on the Pacific side.
Largely wind driven recently and probably not what Bones implied.
Title: Re: The 2018 melting season
Post by: FishOutofWater on March 28, 2018, 03:49:42 PM
Was the transpolar drift ever anything but a general tendency for ice to pile up on the north shores of Ellesmere Island and Greenland and to flow out the west side of the Fram strait. Was it every anything but a situation where most rubber duckie would eventually work their way from the Bering strait to the Fram strait. Was it ever anything but a general observation that ice is thicker on the Canadian side of the Arctic than the Siberian side?

Or has something changed?

The repeated melt outs of the last decade in the Beaufort and Chukchi seas have surely changed the dynamics of ice motion because thick ice that used to rotate for 5 years or more in the Beaufort gyre melts out now. Ice goes to the Beaufort sea to die now. It doesn't live to a ripe old age anymore. The loss of thick ice in the Beuafort gyre has changed the dynamics of flow in the Arctic ocean. Thinner ice moves faster. A number of journal articles discuss the effects of ice thickness and open water on the motion of ice and water in the Arctic. Numerical models of ice dynamics predict increasing flow through the CAA. So we know there are changes in flow and that change will continue as ice thins in the CAA.

But based on what has been reported about the variability in the Arctic oscillation and other indicators of atmospheric dynamics in the Arctic, I doubt that the "transpolar drift" was ever anything but a very general simplification based on the observation that ice piles up on the north shores of Greenland and the CAA.

It's easy to track the train of thick ice that was in the CAA that has rotated around the displaced Beaufort gyre this fall and winter on the JAXA RGB map. Tracking other features is not so easy because of zones of compression, extension and shear. The ice pack is constantly deforming.
Title: Re: The 2018 melting season
Post by: uniquorn on March 28, 2018, 04:44:24 PM
Clearer weather north of Greenland allows a decent view of the thinner ice that remains of the storm damage and the ice front expanding drifting into the Fram Strait. Mar25-28.

Worldview brightness temperature band 15, night squashed palette
Title: Re: The 2018 melting season
Post by: Tor Bejnar on March 28, 2018, 06:28:52 PM
The O-Buoy Project (http://obuoy.datatransport.org/monitor#overview/gpstracks) shows a little evidence of historical trans-polar drift.
Title: Re: The 2018 melting season
Post by: romett1 on March 28, 2018, 06:57:12 PM
Bering Sea ice area (5-day trailing average) has dropped additional 13,000 km² (NSIDC). 2007 - 2017 average reached current level 56 days later on May 22. As southerly winds are dominating between March 29 and April 1, there should be further declines (on excel sheet) starting somewhere after March 30. Looking at April 2 on earth.nullschool we can still see mild temperatures over Bering Sea and Chukchi Sea.
Title: Re: The 2018 melting season
Post by: Shared Humanity on March 29, 2018, 01:01:32 AM
Clearer weather north of Greenland allows a decent view of the thinner ice that remains of the storm damage and the ice front expanding into the Fram Strait. Mar25-28.

Worldview brightness temperature band 15, night squashed palette

Expanding is not how it should be described. The ice is drifting into Fram Strait where it will travel to its doom.
Title: Re: The 2018 melting season
Post by: uniquorn on March 29, 2018, 01:17:53 AM
Thank you for that correction Shared Humanity. I've edited the original.

dmi 80N temperature chart:


Title: Re: The 2018 melting season
Post by: be cause on March 29, 2018, 01:29:03 AM
Hi Shared Humanity ; surely it is expanding .. the front is advancing every day .. the ice behind it is fracturing and freezing . There are numerous such fracture zones atm .. those between Greenland and the pole are particularly active . .
I am feeling the chill of the trans polar drift here in N. Ireland . I seem unable to return to sender .. b.c.
Title: Re: The 2018 melting season
Post by: Thomas Barlow on March 29, 2018, 02:06:13 AM
Is it possible the slight difference in extent, showing on NSIDC 'Charctic', between 2018 and 2017 (lowest for this date, and maybe 2006), the main difference is just the stuff peripheral to the Arctic Ocean around Novaya Zemla?
http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

Title: Re: The 2018 melting season
Post by: FredBear on March 29, 2018, 05:09:17 AM
The transpolar drift was the name given to the general direction taken by ice in the past - it took the Fram nearly three years to go with the flow, (& miss the pole!) from 1893 - but the Tara only took about 2 years (2006-8). Recently the ice seems to have lost its drift   .    .    we have a different Arctic for these seasons?
Title: Re: The 2018 melting season
Post by: Sterks on March 29, 2018, 11:38:39 AM
Fram export was especially vigorous in 2007 so I am not sure if that 2006-2008 example compares well with more recent seasons.
In my opinion, it is more than probable a long-term trend of the ice becoming more mobile, but the overall drift (in pattern and intensity) for each winter seems highly variable.
Title: Re: The 2018 melting season
Post by: Neven on March 29, 2018, 12:35:34 PM
The ECMWF forecast is very interesting right now. The high pressure area west of Alaska that is causing the southerlies which push the ice northwards, is about to intensify and then move into the Central Arctic five days from now, where it is projected to reach 1055 hPa. Now, that's high. The sun is probably too low for any solar radiation to make an impact, but it's still impressive. It might also start pulling the ice away from the Siberian coast. And then, of course, there's the transport towards Fram.

Here's the 6-day forecast below (from Tropical Tidbits). The template I use for this, is for the melting season proper, which is why the North Pacific isn't shown:
Title: Re: The 2018 melting season
Post by: Niall Dollard on March 29, 2018, 12:46:33 PM
The ECMWF forecast is very interesting right now. The high pressure area west of Alaska that is causing the southerlies which push the ice northwards, is about to intensify and then move into the Central Arctic five days from now, where it is projected to reach 1055 hPa. Now, that's high. The sun is probably too low for any solar radiation to make an impact, but it's still impressive. It might also start pulling the ice away from the Siberian coast.

Whatever about the Siberian coasts, it could also promote more lift off in the eastern Beaufort (which has already begun !) 
Title: Re: The 2018 melting season
Post by: Neven on March 29, 2018, 01:19:16 PM
Whatever about the Siberian coasts, it could also promote more lift off in the eastern Beaufort (which has already begun !)

Yes, that too.  :)

I haven't been looking at satellite images lately, but do I see algal blooming below the clouds in the Bering Sea?

(https://lance-modis.eosdis.nasa.gov/imagery/elements/MODIS61/MYGCR_NQD_143/MYGCR_NQD_143_r05c01/2018088/MYGCR_NQD_143.A2018088.r05c01.006.2km.jpg)
Title: Re: The 2018 melting season
Post by: uniquorn on March 29, 2018, 01:48:40 PM
Whatever about the Siberian coasts, it could also promote more lift off in the eastern Beaufort (which has already begun !)
I was just looking at that. Beaufort is mobile despite low temperature anomalies. It will be interesting to see what happens with warmer weather forecast.
Mar18-28

Worldview brightness temperature,band15,night,squashed palette
Title: Re: The 2018 melting season
Post by: A-Team on March 29, 2018, 05:22:21 PM
The winds continue to blow south across the Barents Line (rather than zonally CW in accordance with a persistent polar high ringed by lows), pushing the ice in this sector forward at 5 km/day along a 1000 km line up towards Svalbard and FJL; overall ice motion is very complex because wind stress is very unevenly applied and the icepack is not frozen solid enough to move as a rigid body.

Since the surface water is so warm here per Mercator Ocean, the advected ice will largely melt in situ, not even surviving to melt as export into the Barents proper. This type of 'export' contrasts with the Fram and under-sea moorings there that can measure ice volume prior to melt.

The long dark tongue of Kara ice that began intruding into the Arctic in late November has disintegrated almost overnight, even at the resolution of Ascat (which is 2x better than the Jaxa up-forum). Watch the last 2-3 frames of the mp4 to see this unfolding; GFS wind forecasts suggests this will continue for several more days (though the overall wind pattern is chaotic).

That major northward flow of ice does not remotely fit into the TransPolar Drift paradigm -- which is not a casual figure of speech but often included as a figure in peer-reviewed climate science journals. It is a hang-over from ENSO-NAO teleconnection theory with little explanatory power for Arctic Ocean ice movement over the last year.

We have seen 29 straight days of cloud street on WorldView VIIRS. They are also visible on Sentinel-1B even though the active radar there normally sees through clouds; these may be ice or turbulence has entrained salinity.
Title: Re: The 2018 melting season
Post by: FishOutofWater on March 29, 2018, 05:38:59 PM
Last year there was a larger than normal amount of cyclonic flow in the Arctic. From 1988 to 1995 the flow was very cyclonic over the Arctic ocean. Cyclonic flow is incompatible with "transpolar drift".

There is nothing wrong with the observations of the ships drifting towards the Fram strait, but we shouldn't cherry pick those 2 events to represent "how things used to be." Atmospheric and oceanic flow patterns in the Arctic were very different in the periods 1988-1995 and 1996-2005.

There are natural "cycles" in the Arctic oscillation and there are the effects of climate change and reduced ice volume and thickness on top of the natural oscillations. The lack of transpolar drift in a predominantly cyclonic year, however, is to be expected. The O - buoy data reflect the complexity of what actually happens in the Arctic. The concept of transpolar drift is a gross simplification.
Title: Re: The 2018 melting season
Post by: uniquorn on March 29, 2018, 10:11:24 PM
I think the 'Greenland ratchet' is temporarily disabled.
Mar25-29
[edit]-just checked and there was similar movement in 2017, without the open water event.

Worldview viirs brightness temperature band15,night,squashed pallette
Title: Re: The 2018 melting season
Post by: bbr2314 on March 29, 2018, 10:28:06 PM
The situation in Bering is obviously worsening each passing day, and now another major injection of Pacific saltiness is about to enter Chukchi. This one should be bigger than any to date and may be sustained for quite some time. I wonder if we see complete melt-out of Chukchi and Beaufort by 6/1?

(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticsss_nowcast_anim30d.gif)
Title: Re: The 2018 melting season
Post by: jdallen on March 29, 2018, 11:22:11 PM
The situation in Bering is obviously worsening each passing day, and now another major injection of Pacific saltiness is about to enter Chukchi. This one should be bigger than any to date and may be sustained for quite some time. I wonder if we see complete melt-out of Chukchi and Beaufort by 6/1?

Not ready to predict *that*, but for sure, current conditions are at least 6 weeks ahead of a "typical" melt season.
Title: Re: The 2018 melting season
Post by: A-Team on March 30, 2018, 12:58:08 AM
Quote
It's easy to track the train of thick ice that was in the CAA that has rotated around the displaced Beaufort gyre this fall and winter on the JAXA RGB map. Tracking other features is not so easy because of zones of compression, extension and shear. The ice pack is constantly deforming.
Right. While the Jaxa polarized radar gives some very interesting effects, it does not have nearly the feature resolution of Ascat in newer ice regions where it lacks recoverable contrast. Minor weather artifacts can also be seen passing over the ice, as with many other radar products such as DMI ice surface temperature.

As described up-forum, the best/easiest quantitative approach to describing ice pack motion over an 8 month season is via a delauney feature tesselation. The real question though is how to optimally expand the motion into components, for example zonal and radial, as these would allow more nuanced year-on-year comparisons. Another approach is through plasticity as compression and extension are largely localized to thinner peripheral FYI and SYI, with central MYI undergoing more brittle shear but retaining inter-feature relational geometry over much longer time frames.

Technical note: Jaxa provides a very sophisticated web site, with good control over various animation services. These are in the new webm format developed by google which is not yet portable here. The products are scaled up effectively but way beyond their actual ground resolution which is just ~350 pixels from the Bering Strait to Svalbard. The graphics need a 135º rotation to orient them with Greenland down. They do not readily rescale to Ascat and may be in another projection.

https://ads.nipr.ac.jp/vishop/#/gallery/&time=2018-02-18%2000:00:00
Title: Re: The 2018 melting season
Post by: JayW on March 30, 2018, 01:06:00 AM
100 hour loop, Beaufort region, March 25-29.

https://weather.us/model-charts/euro/usa-east/significant-weather/20180401-0600z.html
Title: Re: The 2018 melting season
Post by: A-Team on March 30, 2018, 03:05:39 AM
Quote
100 hour loop, Alaskan coast, March 25-29.
Nice resource, thx for regular tracking of this. Jay.
Title: Re: The 2018 melting season
Post by: slow wing on March 30, 2018, 03:09:09 AM
  Concerning the discussion above, I really like the vectorized sea ice motion maps we see that are plotted for 1 day's motion if I recall correctly.

Question: does anyone do them for longer time periods? Weekly, or even monthly or for an 8 month melt season?

Would showing such ice vector displacement maps be instructive or not? For example, would they inform discussions on trends and tendencies in seasonal ice motion?

Technically I suspect they are doable, given that the daily maps exist and that the human eye can easily follow the ice motion in the plots above that A-team has kindly posted. (I realise that it is in 2 dimensions that humans have traditionally best out-performed computers.)

Sorry I don't have the skills or commitment to do them myself but I'm guessing they would be interesting  :D
Title: Re: The 2018 melting season
Post by: A-Team on March 30, 2018, 03:25:14 AM
Quote
really like the vectorized sea ice motion maps we see that are plotted for 1 day's motion if I recall
There are an 80-day and 202 day animations of OSI SAF on the Page One section of this forum that could easily be extended or updated; it takes two-day intervals in order to reduce errors with small measurements. There is another version at Jaxa that has speeds colored as well as the vector overlay. NSIDC also has a version that is not so convenient. I don't know if these were derived independently. RASM-ESRL also offers a forecast for five days out.

I believe we could roll our own one-days in contrast-enhanced Ascat since multiple high-end tools are a strong feature of ImageJ. As mentioned, gridded motion vectors do not give integrable solutions (particle trajectories) but those are again easy to do in ImageJ on Ascat.

https://forum.arctic-sea-ice.net/index.php/topic,2278.msg146696.html#msg146696
https://ads.nipr.ac.jp/vishop/#/gallery/&time=2018-02-18%2000:00:00
ftp://ftp1.esrl.noaa.gov/RASM-ESRL/ModelOutput
Title: Re: The 2018 melting season
Post by: Neven on March 30, 2018, 10:38:45 AM
  Concerning the discussion above, I really like the vectorized sea ice motion maps we see that are plotted for 1 day's motion if I recall correctly.

Question: does anyone do them for longer time periods? Weekly, or even monthly or for an 8 month melt season?

Something like this (http://ftp://ftp.ifremer.fr/ifremer/cersat/products/gridded/psi-drift/quicklooks/arctic/merged-ascat-ssmi/30-days_missing_values_filled/)? edit: the link doesn't work because http:// keeps getting put in front of the address: ftp://ftp.ifremer.fr/ifremer/cersat/products/gridded/psi-drift/quicklooks/arctic/merged-ascat-ssmi/30-days_missing_values_filled/

I use these images for the annual winter analysis.
Title: Re: The 2018 melting season
Post by: numerobis on March 30, 2018, 01:17:00 PM
Big storm over Hudson Bay the past couple days. Not particularly strong but its arms have swept by southern Baffin and got us some strong, warm southeasterlies.

It’s dying off now, but a system coming off Labrador this weekend is forecast to bring us near-freezing temperatures, even a risk of rain.
Title: Re: The 2018 melting season
Post by: be cause on March 30, 2018, 03:30:46 PM
there's an unusually good view of the pole using Uniquorn's favoured night view on Worldview ..see reply 152 for better guidance . As such a view seems unavailable for previous years (or recent days) there is little to compare it with .. but the ice is certainly mobile and very fractured .. b.c.
Title: Re: The 2018 melting season
Post by: A-Team on March 30, 2018, 04:01:45 PM
Neven, I've looked at that before and don't think 30-day jumps are a good approach to ice motion trajectories (the daily Ascat animations for their time periods are below, Ascat is what they are using). The September through March trajectories do not correspond to stringing together these monthlies: all the intermediates are missed, including the late February storm. Note the archive skips over the months of June, July and August which are difficult but not impossible to track centrally.

The T Lavergne daily two-day product now over at OSI SAF is a better starting point; it has error analysis and corresponds very closely both with nullschool GFS winds and what the eye sees flashing consecutive days. His twitter site sometimes animates these and provides updates to his earlier motion publications (provided up-forum).

Not sure why you posted January as the February product to March 03 is also available. The Feb looks properly chaotic but the Jan seems just plain wrong. The freeze season 2018 SONDJFM are below. I wonder if they are just adding up gridded dailies (which will accumulate hopeless levels of error) rather than comparing two 30-day jump images which would take misleading vector shortcuts to net motion.

We could have the whole daily Ascat series of the last 11 years quantitatively trajectorised in triplicate with self-correcting error, updated in NRT by remote sensing human PhD's over in India for a small fraction of what is being spent on unsatisfactory ice motion AI:

Quote
Video shows moments before fatal Uber crash in Tempe

Mar 21, 2018 - Tempe police have released two angles of a fatal crash involving a self-driving Uber SUV and a pedestrian on March 18, 2018. Uber. Tempe ... Elaine Herzberg of Mesa was walking a bike across Mill Avenue outside of a crosswalk near the Marquee Theatre when she was hit, police said. [The driver was looking at her cell phone, the road is adequately lit at this location, the car uses Lidar in any event.]

Mobileye, which makes chips and sensors used in collision-avoidance systems and was a supplier to Aptiv Plc, the auto-parts maker that supplied the vehicle’s radar and camera, said it tested its software on the crash video and found it detected the cyclist:

“The video released by the police seems to demonstrate that even the most basic building block of an autonomous vehicle system, the ability to detect and classify objects, is a challenging task,” Mobileye CEO Amnon Shashua wrote on Intel’s website.

http://ktar.com/story/2003896/report-uber-disabled-collision-avoidance-tech-in-tempe-crash-car/?

http://ktar.com/story/2003896/report-uber-disabled-collision-avoidance-tech-in-tempe-crash-car/?

Minor points that suggest an unattended French autonomous vehicle: a lost ice boundary in the February (all blue background) and text 'd' still running off the margin, a bug already in the Jan 2007 (though ftp mod dates indicate Nov 2016).

ftp://ftp.ifremer.fr/ifremer/cersat/products/gridded/psi-drift/quicklooks/arctic/merged-ascat-ssmi/30-days_missing_values_filled/
Title: Re: The 2018 melting season
Post by: A-Team on March 30, 2018, 05:45:21 PM
Quote
unusually good view of north pole on Worldview .. view seems unavailable for previous years so little to compare it with .. but the ice is certainly mobile and very fractured
Right, the north pole is an unfavorable area because of clouds, the off-center orbits of near-polar sun-synchronized satellites and especially by the way WV tiles up images with different time stamps  like day-old pizza slices. Sentinel-1AB has far better resolution but its swath is not wide enough to include the pole, https://www.polarview.aq/arctic.

The NP is mostly political theater: it is not the cold pole, it is not in the center of the Arctic Ocean, it has the same daylight hours over a year as everywhere else, it is only a singularity in selected coordinate systems, it has no special role in the ice pack's future.

Overall, while fractures are important to melt pond drainage and floe separation, it has proven very difficult to compare year on year or quantitate fracturing to get at changes in late season mean floe 'caliper' size, (with the AI for that done quite well in ImageJ). Ice ridges and freeboard edges act as sails that catch the wind and put the ice in motion in more direct proportion to a seasonally changing power law of wind velocity.
Title: Re: The 2018 melting season
Post by: Neven on March 30, 2018, 10:41:10 PM
Neven, I've looked at that before and don't think 30-day jumps are a good approach to ice motion trajectories (the daily Ascat animations for their time periods are below, Ascat is what they are using). The September through March trajectories do not correspond to stringing together these monthlies: all the intermediates are missed, including the late February storm. Note the archive skips over the months of June, July and August which are difficult but not impossible to track centrally.

You're probably right. It was the only thing I could think of when slow wing asked his question. I wish there was something better that was easy to get for a guy like me, who can't make it himself. Same for ice age. Or melt ponds.

Quote
Not sure why you posted January as the February product to March 03 is also available.

I just wanted to post an example. The March image looked a bit weird (no ice).
Title: Re: The 2018 melting season
Post by: Neven on March 30, 2018, 10:47:49 PM
Barentsz is still going up, and might go up some more, given the current forecast. But Hudson has started to go down a bit, and Okhotsk is probably going to drop very fast from now on.
Title: Re: The 2018 melting season
Post by: A-Team on March 30, 2018, 11:18:28 PM
Quote
guy like me, who can't make it himself.
We are to believe this after seeing that elegant new graphic with all the years from 2006-2017 circling around a large 2018? Not!

http://neven1.typepad.com/.a/6a0133f03a1e37970b01b8d2e5c4c1970c-800wi

Per request from FishOut, Jaxa and Ascat are compared below for 208 days, from Sept 1st of last year through March 28th of this year. Between the two of them, we have a very good idea of how recognizable ice features moved, rotated, elongated, compressed, broke apart, left or entered the area or were otherwise distorted over this time frame.
Title: Re: The 2018 melting season
Post by: Shared Humanity on March 30, 2018, 11:31:16 PM
Just wow!
Title: Re: The 2018 melting season
Post by: Tor Bejnar on March 31, 2018, 01:54:43 AM
I don't know the cause (my MacBook Air running Yosemite or internet provider?), but most of your GIFs give the equivalent of this (screenshot of center of GIF):
Title: Re: The 2018 melting season
Post by: A-Team on March 31, 2018, 04:30:59 AM
Quote
MacBook Air running Yosemite or internet provider
That's unfortunate. These are in the common .mp4 format, converted by a very experienced formatting conversion service, https://www.online-convert.com/. The other forum options were mpg mp4, m4v, mov, avi and did not seem to work.

Jaxa is using webm for html5 as that gets around a lot of issues that patent trolls like Nokia have. Does that format work for you?  https://ads.nipr.ac.jp/vishop/#/monitor

We had to move on from .gif because of file size issues. Some of the season-long files are over 100 MB as gifs, unworkable on the forum.

The mp4 don't always load for me right away so I try a reload, or hit the start button. But your attachment suggests you are not even reaching the forum's video player controls. But 'network error', that sounds like your provider. Have you never gotten any of the mp4's to play or is it just today?

Try downloading the file to your hard drive. These have all been tested on QuickTime for the Mac and all work right away. Even for someone running four operating systems behind the curve, it should certainly work.

I use Opera 52.0 on an iMac 13.3.3 High Sierra. The mp4 do not load in Safari 11.03 which lags in many other respects, though I do get a different controller. They load fine in Chrome 65.0.3325 as dnem notes below. So it appears Safari is the problem. Desktop development has not been a priority since the iPhone took off.
Title: Re: The 2018 melting season
Post by: dnem on March 31, 2018, 02:05:49 PM
I can't run A-Team's .mp4s in Safari on my Macbook but they run perfectly in Chrome.  FYI.
Title: Re: The 2018 melting season
Post by: uniquorn on March 31, 2018, 03:05:20 PM
The first few frames of large mp4's play ad then I get a video stopped loading error:). They run ok when I download them.

Lovely view of the Sea of Okhotsk today on Worldview. A few days of warmer weather forecast.
Title: Re: The 2018 melting season
Post by: A-Team on March 31, 2018, 04:37:38 PM
Quote
The first few frames of large mp4's play ad then I get a video stopped loading error:).
Ads for what, in which mp4 above? Browser and operating system? Sounds like your mp4 player has been hijacked, with remote ads injected and kickbacks to the browser company. Whatever the Mac browser, obnoxious strangers can turn up the volume on a movie audio without your permission and without any means of revoking permission enabled.

Quote
Early melt ponds are so important to the overall melt season, what are the best online tools for following their development?
Good question. RASM-ESRL does offer daily melt ponds and albedo plus their forecasts; whether these correspond to ground condition reality is another matter.

Summer imagery s overwhelmed by passing weather in both Ascat and Jaxa so I've been looking at extending them to year-round utility via color space deconvolution into a weather-minimizing channel.

The ones that ImageJ has "in stock" have to do with optimizing immunohistochemistry stain visualization; the one below uses the 3rd channel of alcian blue & hemolysin basis vectors on Jaxa for June, July and August 2017. This does quite a good job on suppressing noise past the sea edge but is likely far from optimal. (I have not gotten around to the two 'rational' options that base off user-picked regions of interests or an inspired/deduced RGB rotation matrix.)

Channel mixing was discussed here many many moons ago, in the context of petroglyph enhancement where it has revolutionized photographic preservation of faded and vandalized artwork. The approach was to rapidly scroll through many dozens of color spaces, then zoom in on a good one, rather than proceed from model and theory.

Here Jaxa has 3 channels of color whereas Ascat has 1, or 2563 vs 256. While the Jaxa channels are fairly well correlated, they can be maximally de-correlated.
Title: Re: The 2018 melting season
Post by: uniquorn on March 31, 2018, 04:59:42 PM
Sorry.

The first few frames of large mp4's play and then I get a video stopped loading error:). They run ok when I download them.
Title: Re: The 2018 melting season
Post by: Tor Bejnar on March 31, 2018, 05:02:20 PM
Quote
MacBook Air running Yosemite or internet provider
...These are in the common .mp4 format ... [I used "GIF" generically, for "movie".  Sorry for my sloppy communication.]

Jaxa is using webm for html5 as that gets around a lot of issues that patent trolls like Nokia have. Does that format work for you?  https://ads.nipr.ac.jp/vishop/#/monitor  [I clicked on this link, clicked "Save as animation", and could see frames getting added to the picture behind the status/progress box.  After about 2 minutes it got to 97% when it stopped progressing (no additional progress after 5 more minutes).]

... But 'network error', that sounds like your provider. Have you never gotten any of the mp4's to play or is it just today?  [Has never worked from home.  I see them fine at work.  Living rural, my Centurylink is slow: Download 3.06 Mbps Upload 0.63 Mbps.  I use Firefox, by the way.]

...
I'll watch them at work (during breaks, of course).
Title: Re: The 2018 melting season
Post by: Jim Hunt on March 31, 2018, 05:40:52 PM
A new open access paper in GRL from Alek Petty:

"A Possible Link Between Winter Arctic Sea Ice Decline and a Collapse of the Beaufort High? (http://)"

Quote
A new study by Moore et al. (2018, https://doi.org/10.1002/2017GL076446) highlights a collapse of the anticyclonic “Beaufort High” atmospheric circulation over the western Arctic Ocean in the winter of 2017 and an associated reversal of the sea ice drift through the southern Beaufort Sea (eastward instead of the predominantly westward circulation). The authors linked this to the loss of sea ice in the Barents Sea, anomalous warming over the region, and the intrusion of low‐pressure cyclones along the eastern Arctic. In this commentary we discuss the significance of this observation, the challenges associated with understanding these possible linkages, and some of the alternative hypotheses surrounding the impacts of winter Arctic sea ice loss.
Title: Re: The 2018 melting season
Post by: uniquorn on March 31, 2018, 07:29:58 PM
A partially refrozen lead in the Svalbard and FJL area. Probably not significant yet. Nullshool has temperature <-20C so it should freeze over completely. Mar31

Worldview Terra Modis
Title: Re: The 2018 melting season
Post by: A-Team on March 31, 2018, 08:45:03 PM
Firefox 58.0.2 works just great on forum mp4's. In fact it offers speed controls. Initially though I got the same fail screen that you had.

Quote
CenturyLink  :'( :-\ :(
That explains a lot right there. Gifs are animations. Single frames that fly by one at a time. When you download and open, each frame shows up as an independent layer. They can be compressed but only to the extent that frame n+1 reuses a lot of material from frame n. Mp4s are videos. They are eye-foolers, compressed in 2D+T. You can stop-action but not recover the frames from which it was made.

Gifs are preferable scientifically because each frame represents a day of data, presented without loss, and thus conveyed to the next person to work with. Videos can convey ideas very well using much small files but lose data details, so they are just climate theatrics and not an acceptable way to distribute data.

Jaxa has the most sophisticated code I've seen to date on a climate science portal. They are using the webm format for videos, open source codecs championed by google. Neven would have to enable that in admin attachment permissions. I converted some of the mp4 here into webm and tested them on Opera, Chrome, Firefox and Safari. Again, all but Safari worked perfectly.

The Arctic Ocean occupies only a third of the Jaxa video area. However free online cropping is available at https://ezgif.com/crop-video as well as https://www.online-convert.com. However rotations are restricted to multiples of 90º whereas Jaxa animations need 135º.
Title: Re: The 2018 melting season
Post by: Neven on March 31, 2018, 10:00:03 PM
We are to believe this after seeing that elegant new graphic with all the years from 2006-2017 circling around a large 2018? Not!

I can do some basic copy/Paste stuff in Photoshop. I know how to create 'actions', so I don't have to repeat the same operations for each image. But I don't know how to squeeze out extra information by using filters, like you do, let alone set up scripts that retrieve data and turn them into visual graphs and maps, that are easy to grasp (like dryland is doing with RASM project).

I wish I could , though. I'd be rocking hard. We could even join forces and create WAN University (Wipneus, A-Team and Neven) to compete with the real science institutions.  8) ;D
Title: Re: The 2018 melting season
Post by: A-Team on March 31, 2018, 11:56:01 PM
Quote
we could compete with the real science institutions?
That would be a lark. We can definitely get some decent stuff out the door in near-real time. That's the future, not 36 months of chewing cud that our forums could have spewed out while still at sea (N-ICE2015?).

JimH brought attention in #176 above to a well-written commentary piece on an interesting Arctic Ocean gyre piece. The analysis below only gets as far as Fig.1b which "averages" ice motion vectors over Jan-Mar 2017.

That didn't make a great deal of sense to me because averaging loses all track of time ordering (scramble the order, get same result) so with many grid points averaged separately and potentially relatively scrambled, it doesn't follow that vector field correlation would be retained. Sure enough [Frobenius 1877], the outcome is only so-so as an overlay on real data.

The January-only story of Fig.2 is very wrong, which favors the original Moore 2018 story and Zabolotskikh 2018 discussed in #1474 of the freezing season forum.

Technical note: Motion detection algorithms have received an incredible amount of development, not only from science side (cell  and organelle movement, ice sheets advancing, asteroids moving against fixed stars ) but also video games and commercial AI applications such as security cameras, robotic computer vision and autonomous vehicle object recognition and classification.

These algorithms work by identifying scene changes, in the case here from a pair of consecutive grayscale Arctic Ocean images in the Ascat daily time series. The central problem is reliable displacement vectors are very unevenly distributed across the scene, first because the ice pack does not move uniformly as a rigid body but notably deforms, and second because of uneven availability of local contrast.
For example, if a pixel is say gray 128 and part of a large dull patch of gray 128±3, it won’’t be possible to tell where the point went on day 2 because it lacks the distinct local signature that’s key to its recognition in the displaced image.

Because both the displacements and the Ascat images are pixelated (ie integers rather than continuous), round-off errors are especially serious with small displacements. This cannot be overcome by fitting splines or bumping to much higher resolution with say bicubic enlargement to make the displacements larger because those processes have limits tied to the original resolution. That is, over a day, a feature might only move half a pixel but that would have to be treated as 0 or 1 pixels of displacement. If it moved 5.5 pixels, round-off to 5 or 6 wouldn’t be so serious in percentage terms.

As a practical matter, much of the central ice pack is hardly moving whereas peripheral areas can see displacements of a km/hr. For this reason, OSI SAF uses 48 hour intervals instead of 24 to reduce error. (These overlap oddly: day n is determined by differencing day n-1 and day n+1, the following day by day n and day n+2.)

Consequently, starting with the mindset of a fixed rectangular gridded array (ie a certain resolution), the grid points themselves won’t often be assigned displacement vectors directly. Instead, whatever favorable points in the scene that can be assigned accurate displacements are interpolated onto the grid, typically by kriging. We’ve seen this before in Greenland bedrock determination — polygons of 10,000 sq km that never received an over-flight with ice-penetrating radar.

So not only does each displacement vector have variable associated error, interpolation to the grid brings in additional error, with very uneven accuracy over the scene depending on the distribution of favorable regions for motion detection. The gridding process gets repeated for each pair of consecutive days to produce the daily OSI SAF gridded vector graphic, even though the set of favorable points is not time-transitive (ie, the trajectory of an initially favorable point won’t necessarily be followed across the time series).

Here the central issue is optimal pre-processing of Ascat contrast prior to applying the displacement algorithm to the daily pair. If the pair is used ‘as-is’, errors will be horrible because the original contrast is uncorrected and the central ice pack is uniform gray. A much more effective method is to first change the initial RGB gif to 8-bit gray to 32-bit gray. This seems strange since the image actually only has 7-bit information but three rounds of bicubic enlargement, contrast stretching and moderate adaptive contrast adjustment all involve round-off errors , dumbing down to the prevailing bit depth bins. It is better to do a single round-off step back to 8-bit at the end. The adaptive contrast step is very important to increasing the availability of accurate local displacement vectors, as is bicubic vs bilinear 2x enlargement. Done in moderation, these steps do not introduce artificial displacements, as can be seen from the internal consistency of the product across 200 days of imagery.

Thus over a month, the interpolation process will have been carried out 30 separate times, so averaging the 30 vectors at each grid point will accumulate all the initial and interpolation errors there. Since the averaging process loses all track of time order, all correlation to other grid points being averaged is lost. Note too, gregorian months are arbitrary time divisions out of synch with natural seasonal divisions; it is imperative to test such slicing for bias by rolling 30-day winds to assure robustness of a particular calendar month view.

 For these reasons, it is better to determine a reasonably dense set of actual particle trajectories because positional error self-corrects (resets each day) instead of accumulating. Further the subset of daily points for the set of trajectories retains positional correlation (delauney triangulation) and provides the polygons that measure ice pack deformation.
Title: Re: The 2018 melting season
Post by: uniquorn on April 01, 2018, 06:30:11 PM
Chukchi Sea Mar23-Apr1

Worldview Terra/Modis
Title: Re: The 2018 melting season
Post by: Neven on April 01, 2018, 07:20:51 PM
Now that the month is full, here's the final bar graph showing March average for Bering Sea SIA. And here's the top 5:

2001: 401 K
2015: 369 K
1996: 341 K
1989: 310 K
2018: 172 K
Title: Re: The 2018 melting season
Post by: Shared Humanity on April 01, 2018, 07:35:25 PM
If I were to look at this data without anything else to inform my analysis, I could not conclude that this years record low was anything more than random variation, an outlier that happens but only rarely.

Heck, the cluster of 4 record highs in a 6 year span from 2008 to 2014 seems to suggest we are moving towards more ice coverage not less.
Title: Re: The 2018 melting season
Post by: Archimid on April 01, 2018, 07:41:10 PM
I was reading a bit on Arctic sea ice melt dynamics and stumbled upon this paper.

Winter-to-summer transition of Arctic sea ice breakup and floe size distribution in the Beaufort Sea
https://www.elementascience.org/articles/10.1525/elementa.232/

For brevity sake I will not post the abstract but this paper discusses ice melt in the Arctic using  buoys and satellite imagery.  They discuss melt in all directions and at different stages of the melting season in 2014. I find this graph from the article to be very insightful as we head into the melting season:

(https://www.elementascience.org/articles/10.1525/elementa.232/elementa-5-232-g3.png)
Title: Re: The 2018 melting season
Post by: be cause on April 01, 2018, 07:58:39 PM
having a good look again on Worldview at the fracturing/freezing going on across the Arctic .. all this fresh freezing must affect the under ice water temps . It is also allowing for growth and spread of the Arctic to replace export as it happens . It looks to me that this activity is increasing as the ice becomes younger and thinner ( also a cause .. ) . Any analysis of what is happening would be appreciated .. b.c.
Title: Re: The 2018 melting season
Post by: Alexander555 on April 01, 2018, 08:01:26 PM
If I were to look at this data without anything else to inform my analysis, I could not conclude that this years record low was anything more than random variation, an outlier that happens but only rarely.

Heck, the cluster of 4 record highs in a 6 year span from 2008 to 2014 seems to suggest we are moving towards more ice coverage not less.

I think that's the result from the weaker Vortex. 2012 had the highest extent in the Bering Sea and the lowest arctic summer extent in a long time . And this year the Bering Sea is at a record low. Some volatility is kicking in.
Title: Re: The 2018 melting season
Post by: FishOutofWater on April 01, 2018, 08:53:31 PM
La Niña favors a jet stream track across the Pacific that tracks farther north than normal at the dateline. The Rossby wave pattern from strong convection in Indonesia and the western Pacific transports heat in the direction of the Aleutians, and the Aleutian low is weakened.

This winter's low sea ice extent in the Bering sea is consistent with La Niña. There's other stuff, such as climate change going on, of course. Beware of drawing lines through small data sets.
Title: Re: The 2018 melting season
Post by: Shared Humanity on April 01, 2018, 09:33:35 PM
La Niña favors a jet stream track across the Pacific that tracks farther north than normal at the dateline. The Rossby wave pattern from strong convection in Indonesia and the western Pacific transports heat in the direction of the Aleutians, and the Aleutian low is weakened.

This winter's low sea ice extent in the Bering sea is consistent with La Niña. There's other stuff, such as climate change going on, of course. Beware of drawing lines through small data sets.

I think that was my point...that the record low reveals little.
Title: Re: The 2018 melting season
Post by: Neven on April 01, 2018, 09:51:27 PM
If I were to look at this data without anything else to inform my analysis, I could not conclude that this years record low was anything more than random variation, an outlier that happens but only rarely.

Heck, the cluster of 4 record highs in a 6 year span from 2008 to 2014 seems to suggest we are moving towards more ice coverage not less.

Random variation or extreme volatility?  ;)
Title: Re: The 2018 melting season
Post by: oren on April 01, 2018, 10:44:05 PM
The Bering is indeed volatile, but a look at long term ice coverage statistics of its downwind brother the Chukchi (some of which I have posted recently one of the threads) reveals an unmistakable long-term decline trend, which I am certain will see another record season this year.
Title: Re: The 2018 melting season
Post by: A-Team on April 02, 2018, 12:33:02 AM
Quote
Got melt ponds?
May and June melt*ponds and albedo are important to the summer season but who is tracking them  with what satellite and daily web service -- or is this another product that we can do better ourselves?

One way of going is level 3 MODIS bands 1,3,4 because melt-ponds, sea ice, snow on sea ice and open water have sufficiently different reflectance profiles. Given a calibration set tied to ground observation of typical melt stages, the contributions of each to a given image pixel (or rather grid cell) can be obtained by inversion. Dividing by the sea ice concentration of that grid cell then gives the melt-pond fraction relative to the current sea-ice concentration.

The question is, how much of the Arctic Ocean will have clear skies over the eight days? (More recent methods use polarized radar.)

So far, so good -- the 8-day netCDF files are available by open ftp. However they only extend to Sept 2011 though the program mentions a correction made on 25 Oct 2017. The last seven years of data seem to be restricted to insiders.

At any rate, I ran day 137 -161 through Panoply and compared them to Ascat and Jaxa averaged over eight days for the 17 May 2011 date, below. No correlation with melt ponds can be seen. (NOAA's Ascat server was broken down as it often is, so the eight day averaging couldn't be done.)

https://www.the-cryosphere.net/6/431/2012/ original article
https://icdc.cen.uni-hamburg.de/1/daten/cryosphere/arctic-meltponds.html description
ftp://ftp-icdc.cen.uni-hamburg.de/arctic_meltponds/ the netCDF files to Sept 2011

MODIS__MeltPondFraction__UHAM-CliSAP-ICDC__v02__12.5km__2011137.nc  17 May 2011
MODIS__MeltPondFraction__UHAM-CliSAP-ICDC__v02__12.5km__2011145.nc  25 May 2011
MODIS__MeltPondFraction__UHAM-CliSAP-ICDC__v02__12.5km__2011153.nc  02 Jun 2011
MODIS__MeltPondFraction__UHAM-CliSAP-ICDC__v02__12.5km__2011161.nc  10 Jun 2011

Integrated Climate Data Center - ICDC Restricted Access - What does that mean?
This data set is only available for a restricted user group. In the CEN network of the University of Hamburg or from the outside via Login for CliSAP members, you can access links of the restricted area and use the data.  Please contact us, if you are not member of this user group and would like to access these data.
Title: Re: The 2018 melting season
Post by: A-Team on April 02, 2018, 12:53:43 AM
Quote
Chukchi reveals an unmistakable long-term decline trend, which I am certain will see another record season this year.
Good call. Right now though, UH SMOS is showing the Beaufort to have thinner ice than the Chukchi. The Arctic north of the Barents may also have a lot of open water early.
Title: Re: The 2018 melting season
Post by: uniquorn on April 02, 2018, 02:34:00 AM
Yes, beaufort looks bad. Look forward to Jayw next update.
I did a quick reality check on Chukchi going back to 2004. Some clouds, but good enough for comparison.

Worldview Terra/Modis (some differences pre2013)
Title: Re: The 2018 melting season
Post by: jdallen on April 02, 2018, 04:00:01 AM
Quote
Chukchi reveals an unmistakable long-term decline trend, which I am certain will see another record season this year.
Good call. Right now though, UH SMOS is showing the Beaufort to have thinner ice than the Chukchi. The Arctic north of the Barents may also have a lot of open water early.
Concur.  I *really* don't like how that ice is breaking up north of Svalbard.  That's more like what it might look like in May or June, not now.
Title: Re: The 2018 melting season
Post by: sofistek on April 02, 2018, 05:47:26 AM
Heck, the cluster of 4 record highs in a 6 year span from 2008 to 2014 seems to suggest we are moving towards more ice coverage not less.
What record highs? As far as I can tell, the highs for all of those years were below the median high.
Title: Re: The 2018 melting season
Post by: oren on April 02, 2018, 06:38:31 AM
Just to back up my claim of Chukchi trend. NSIDC data of monthly extent and area averages.
I agree other locations currently look worse though.
Title: Re: The 2018 melting season
Post by: Espen on April 02, 2018, 10:09:16 AM
Quote
Chukchi reveals an unmistakable long-term decline trend, which I am certain will see another record season this year.
Good call. Right now though, UH SMOS is showing the Beaufort to have thinner ice than the Chukchi. The Arctic north of the Barents may also have a lot of open water early.
Concur.  I *really* don't like how that ice is breaking up north of Svalbard.  That's more like what it might look like in May or June, not now.

It is not only north of Svalbard, but the break up of sea ice of Jøkelbugt (North East Greenland) is at least 3-4 months ahead of normal, Scoresbysund further south is well ahead too?
Title: Re: The 2018 melting season
Post by: uniquorn on April 02, 2018, 07:22:08 PM
Winter-to-summer transition of Arctic sea ice breakup and floe size distribution in the Beaufort Sea
https://www.elementascience.org/articles/10.1525/elementa.232/

Thanks for this Archimid.
For those who don't have time to read the link. c1 to c4 on the charts are the 4 clusters of buoys. w1 to w7 are wind events.
Title: Re: The 2018 melting season
Post by: subgeometer on April 02, 2018, 11:27:46 PM
It won't be long before the last ice in the Bering Sea gives up the ghost, and the Chukchi Sea doesn't look good. A lot of the ice there must be pretty thin, given that there was open water and sub 0.5m ice only 6 weeks or so ago
Title: Re: The 2018 melting season
Post by: jdallen on April 03, 2018, 12:41:46 AM
It won't be long ebefore the last ice in the Bering Sea gives up the ghost, and the Chukchi Sea doesn't look good. A lot of the ice there must be pretty thin, given that there was open water and sub 0.5m ice only 6 weeks or so ago
Also to factor, we are with in a week or so of reaching "break even" where incoming insolation will balance outgoing long wave radiation from the top of the atmosphere.  The current predicted spasm of inflowing heat will only exacerbate the problem.
Title: Re: The 2018 melting season
Post by: Thomas Barlow on April 03, 2018, 01:15:16 AM
" 'Usually you see a bit of sea-ice along the coasts and if you happen to fly the drone far enough, you may capture some icebergs much further away' Beyzaei told Global News. So Beyzaei was in for an early April Fool's shock on March 27, when he flew his drone off the Newfoundland coast and recorded astonishing footage of sea ice stretching over Brighton, Newfoundland, Global News reported Sunday. "

'Stunning Drone Video of Sea Ice Reveals Unexpected Climate Change Effects'
"..the Arctic has just experienced its warmest winter on record. Arctic sea ice also reached its second-lowest extent on record this year, just barely inching out 2017's ice coverage to avoid being the lowest year for Arctic sea ice ever.
But according to research published in Geophysical Research Letters on March 15 and cited by Global News, footage like Beyzaei's is exactly what you can expect from the impacts of climate change on the Arctic."


https://www.ecowatch.com/sea-ice-drone-newfoundland-2555583953.html
Title: Re: The 2018 melting season
Post by: Daniel B. on April 03, 2018, 01:16:02 AM
Heck, the cluster of 4 record highs in a 6 year span from 2008 to 2014 seems to suggest we are moving towards more ice coverage not less.
What record highs? As far as I can tell, the highs for all of those years were below the median high.

Look at the graph that Neven posted immediately prior.  The four highest years for Bering sea ice March average ice area were 2012, 2008, 2010, 2013.  His comment about an outlier may prove to be quite accurate, similar to 1989.
Title: Re: The 2018 melting season
Post by: snrjon on April 03, 2018, 07:49:48 AM
Hi, noob question. Arctic sea ice volume increases until mid-April, while the sea ice extent typically peaks a month or so earlier. Melting from the edges is a very obvious cause of extent decrease, but what are the mechanisms that allow growth in volume for a month after the melting begins? Is it addition by freezing to the bottom surface, tectonic squeezing, snow, and what is the most important of these? Thanks for any pointers.
Title: Re: The 2018 melting season
Post by: oren on April 03, 2018, 07:54:08 AM
Hi, noob question. Arctic sea ice volume increases until mid-April, while the sea ice extent typically peaks a month or so earlier. Melting from the edges is a very obvious cause of extent decrease, but what are the mechanisms that allow growth in volume for a month after the melting begins? Is it addition by freezing to the bottom surface, tectonic squeezing, snow, and what is the most important of these? Thanks for any pointers.
Hi snrjon, I've answered you in the "stupid" questions thread (though I do dislike the name - should be "beginner" questions or whatever). https://forum.arctic-sea-ice.net/index.php/topic,143.msg148292.html#msg148292 (https://forum.arctic-sea-ice.net/index.php/topic,143.msg148292.html#msg148292)
Title: Re: The 2018 melting season
Post by: Neven on April 03, 2018, 09:49:13 AM
Hi snrjon, I've answered you in the "stupid" questions thread (though I do dislike the name - should be "beginner" questions or whatever). https://forum.arctic-sea-ice.net/index.php/topic,143.msg148292.html#msg148292 (https://forum.arctic-sea-ice.net/index.php/topic,143.msg148292.html#msg148292)

There's nothing wrong with a good stupid question.  ;D
Title: Re: The 2018 melting season
Post by: oren on April 03, 2018, 10:29:20 AM
Hi snrjon, I've answered you in the "stupid" questions thread (though I do dislike the name - should be "beginner" questions or whatever). https://forum.arctic-sea-ice.net/index.php/topic,143.msg148292.html#msg148292 (https://forum.arctic-sea-ice.net/index.php/topic,143.msg148292.html#msg148292)

There's nothing wrong with a good stupid question.  ;D
I know, stupid is not to ask. But maybe at least change the thread title to "Stupid" questions?
Title: Re: The 2018 melting season
Post by: Neven on April 03, 2018, 10:49:39 AM
Okay, done.  :)
Title: Re: The 2018 melting season
Post by: uniquorn on April 03, 2018, 12:55:36 PM
It won't be long ebefore the last ice in the Bering Sea gives up the ghost, and the Chukchi Sea doesn't look good. A lot of the ice there must be pretty thin, given that there was open water and sub 0.5m ice only 6 weeks or so ago
Also to factor, we are with in a week or so of reaching "break even" where incoming insolation will balance outgoing long wave radiation from the top of the atmosphere.  The current predicted spasm of inflowing heat will only exacerbate the problem.
Agreed. Bering/Chukchi Jan-Mar29
amsr2 uni-hamburg
Title: Re: The 2018 melting season
Post by: Pmt111500 on April 03, 2018, 01:27:53 PM
It won't be long ebefore the last ice in the Bering Sea gives up the ghost, and the Chukchi Sea doesn't look good. A lot of the ice there must be pretty thin, given that there was open water and sub 0.5m ice only 6 weeks or so ago
Also to factor, we are with in a week or so of reaching "break even" where incoming insolation will balance outgoing long wave radiation from the top of the atmosphere.  The current predicted spasm of inflowing heat will only exacerbate the problem.
Agreed. Bering/Chukchi Jan-Mar29
amsr2 uni-hamburg

Again looking like there'd be some pumping action at lunar tempo here but it can't be, can it. ~29 days between local minimums. Noo, it wouldn't, would it?
Title: Re: The 2018 melting season
Post by: oren on April 03, 2018, 02:11:02 PM
Thanks for the animation uniquorn. Very interesting to watch. It does seem that the "native" air temps are sufficient for surface freezing, but heat coming from elsewhere on the wings of the south winds is what gets the ice. As this happened several times this winter, and the ice was too thin to resist, we got the record result.
Title: Re: The 2018 melting season
Post by: uniquorn on April 03, 2018, 02:54:53 PM
I expect sea surface temperature and wave action doesn't help.
Nice view on Worldview today

Terra Modis
Title: Re: The 2018 melting season
Post by: snrjon on April 03, 2018, 03:20:02 PM
Hi snrjon, I've answered you in the "stupid" questions thread (though I do dislike the name - should be "beginner" questions or whatever). https://forum.arctic-sea-ice.net/index.php/topic,143.msg148292.html#msg148292 (https://forum.arctic-sea-ice.net/index.php/topic,143.msg148292.html#msg148292)

There's nothing wrong with a good stupid question.  ;D

Thanks for the answer. Question prompted by noting the DMI volume graph, where there is maybe another 2000-3000 cubic km to reach the peak, before net volume melting takes over.
Title: Re: The 2018 melting season
Post by: guygee on April 03, 2018, 03:40:05 PM
Again looking like there'd be some pumping action at lunar tempo here but it can't be, can it. ~29 days between local minimums. Noo, it wouldn't, would it?
Worth checking out but tides vary only about 1 foot Norton Sound Nome AK,
https://tidesandcurrents.noaa.gov/noaatidepredictions.html?id=9468756 (https://tidesandcurrents.noaa.gov/noaatidepredictions.html?id=9468756)
Title: Re: The 2018 melting season
Post by: A-Team on April 03, 2018, 04:06:37 PM
Quote
Usually you see a bit of sea-ice along the coasts .... on March 27 in for a shock flew his drone and recorded astonishing footage of sea ice stretching over Brighton, Newfoundland 
They don't have internet? Maybe the mp4 below would help, it is an easy daily update. It runs from the first of the year to April 3rd, showing Jaxa, Jaxa inverted, OSI-SAF drift, and AMSR2 sea ice concentration. The town of Brighton NL is marked with a star. Note how Fram ice goes around the tip of south Greenland but almost immediately melts out in the Irminger Current.

This is a quite interesting, easily readable article on Baffin Bay sea ice for 2017

Increasing Mobility of High Arctic Sea Ice Increases Marine Hazards Off the East Coast of Newfoundland
DG Barber et al
https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2017GL076587 open source

During spring 2017 an anomalous ice cover composed of MYI from the High Arctic presented hazardousconditions off the northeast coast of Newfoundland. The ice cover was thicker than is typical of the area and as a result persisted into late June when the area is typically ice-free and maritime traffic can proceed unimpeded by sea ice.

The influence of storm events is compounded by a low internal ice stress field that makes the ice cover more responsive to winds and fosters peak ice drift speeds of up to 75 km/day.

These MYI floes were advected over 3,000 km from the Lincoln Sea and CAA to the coastal waters around Newfoundland within one ice season. Based on tracking the MYI edge, we determine that MYI must enter Baffin Bay through Lancaster Sound between early October and mid-January or enter Nares Strait from the Lincoln Sea between September and December in order to be transported to Newfoundland before the ice edge begins to retreat in early May.

Under a changing climate, the Arctic ice pack has become increasingly mobile, with increased ice drift speeds and increased ice export through narrow channels due to the
reduced likelihood of ice arch formation.
Title: Re: The 2018 melting season
Post by: Pmt111500 on April 03, 2018, 04:37:53 PM
Again looking like there'd be some pumping action at lunar tempo here but it can't be, can it. ~29 days between local minimums. Noo, it wouldn't, would it?
Worth checking out but tides vary only about 1 foot Norton Sound Nome AK,
https://tidesandcurrents.noaa.gov/noaatidepredictions.html?id=9468756 (https://tidesandcurrents.noaa.gov/noaatidepredictions.html?id=9468756)
Thanks for the info. I've seen tides in northern Norway and they're not hugely variable either. The tidal influence on coastal ice should be checked areally as they're of course opposite of each other twice á day. It's possible you can't rely solely on satellites on this as they do not go over at the same area at the same times wrt moon. I've often seen this sort of periodicity seemingly occurring in ice data only to lose it after a couple of months. Common sense would say there is some effect as the high tide would expose more of the ocean under ice but how big the effect would be I've got no idea.
Title: Re: The 2018 melting season
Post by: oren on April 03, 2018, 06:43:29 PM
Thanks for the answer. Question prompted by noting the DMI volume graph, where there is maybe another 2000-3000 cubic km to reach the peak, before net volume melting takes over.
BTW, I find the DMI volume suspect, and much prefer PIOMAS. You can watch Wipneus' latest animation for March to see where PIOMAS thinks the volume is growing. https://forum.arctic-sea-ice.net/index.php/topic,119.msg148336.html#msg148336 (https://forum.arctic-sea-ice.net/index.php/topic,119.msg148336.html#msg148336)
Title: Re: The 2018 melting season
Post by: jdallen on April 03, 2018, 10:35:25 PM
Bering Strait, today.  This is definitively *bad*.

 :o
Title: Re: The 2018 melting season
Post by: Neven on April 03, 2018, 10:58:51 PM
There it finally is, 1051 hPa over the Beaufort. I'll post the forecast tomorrow. It looks like 1030+ hPa will remain a feature over the CAB for the week to come, with potentially a 974 hPa cyclone coming in via Kara. That should speed up transport towards the Atlantic. Not to mention all that sunshine over the Central Arctic. The Sun's probably too low to cause any melt onset, but still... Interesting set-up.
Title: Re: The 2018 melting season
Post by: TerryM on April 04, 2018, 05:22:50 AM
" 'Usually you see a bit of sea-ice along the coasts and if you happen to fly the drone far enough, you may capture some icebergs much further away' Beyzaei told Global News. So Beyzaei was in for an early April Fool's shock on March 27, when he flew his drone off the Newfoundland coast and recorded astonishing footage of sea ice stretching over Brighton, Newfoundland, Global News reported Sunday. "

'Stunning Drone Video of Sea Ice Reveals Unexpected Climate Change Effects'
"..the Arctic has just experienced its warmest winter on record. Arctic sea ice also reached its second-lowest extent on record this year, just barely inching out 2017's ice coverage to avoid being the lowest year for Arctic sea ice ever.
But according to research published in Geophysical Research Letters on March 15 and cited by Global News, footage like Beyzaei's is exactly what you can expect from the impacts of climate change on the Arctic."


https://www.ecowatch.com/sea-ice-drone-newfoundland-2555583953.html (https://www.ecowatch.com/sea-ice-drone-newfoundland-2555583953.html)


FWIW
I spent the last week in May of 2006 ferrying between Northern Newfoundland and Southern Labrador. Tee shirt weather, no snow or ice visible on either side of the Strait of Bell Isle. On our first day in Labrador one small iceberg was spotted.
We had driven through southern Newfoundland in early May and again warm spring weather with no hint of ice.
Beautiful people in a strange land.
Terry
Title: Re: The 2018 melting season
Post by: TerryM on April 04, 2018, 05:39:56 AM
Again looking like there'd be some pumping action at lunar tempo here but it can't be, can it. ~29 days between local minimums. Noo, it wouldn't, would it?
Worth checking out but tides vary only about 1 foot Norton Sound Nome AK,
https://tidesandcurrents.noaa.gov/noaatidepredictions.html?id=9468756 (https://tidesandcurrents.noaa.gov/noaatidepredictions.html?id=9468756)
Thanks for the info. I've seen tides in northern Norway and they're not hugely variable either. The tidal influence on coastal ice should be checked areally as they're of course opposite of each other twice á day. It's possible you can't rely solely on satellites on this as they do not go over at the same area at the same times wrt moon. I've often seen this sort of periodicity seemingly occurring in ice data only to lose it after a couple of months. Common sense would say there is some effect as the high tide would expose more of the ocean under ice but how big the effect would be I've got no idea.


Ungava Bay Canadian arctic - tidal range - 32.0 ft. 2nd highest in the world
Cook Inlet Alaska USA - tidal range - 30.3 ft. 4th highest in the world
Hudson Strait - Canadian Arctic - tidal range - >30 ft


My experience is that during melt season ~2 days after a strong spring tide lots of ice will break away from it's fast connection to shore.


Terry
Title: Re: The 2018 melting season
Post by: romett1 on April 04, 2018, 08:56:51 AM
Bering Strait, today.  This is definitively *bad*.

 :o
As many have pointed out at some point looking at sea surface temperature anomaly chart (Bering Sea and surrounding waters) is even more interesting. Image: http://polar.ncep.noaa.gov/sst/ophi/
Title: Re: The 2018 melting season
Post by: RikW on April 04, 2018, 09:01:46 AM
That isn't really that surprising, since surface temperature won't really get above 0 when there is ice, and now it's gone earlier, so when ice is retreating faster than normal, you see huge temperature anomalies during that abnormally ice-free period
Title: Re: The 2018 melting season
Post by: Neven on April 04, 2018, 02:09:02 PM
For those who haven't seen the 2018 sea ice area and extent data thread (https://forum.arctic-sea-ice.net/index.php/topic,2223.msg148464.html#msg148464) today, JAXA had a big 137K drop (largest March daily drop in the 2005-2018 period), which means 2018 is now lowest on record:
Title: Re: The 2018 melting season
Post by: Neven on April 04, 2018, 02:12:08 PM
As for that ECMWF forecast (provided by Tropical Tidbits), that low is now at D5 at 972 hPa, and over the Barentsz, not Kara, but will impact Kara most. And as said, lots of high pressure over the CAB. The Arctic is extremely lucky it isn't mid-May yet:
Title: Re: The 2018 melting season
Post by: Neven on April 04, 2018, 02:13:43 PM
And, last but not least, I've prepared temperature graphs for the PIOMAS update, and as expected, March was plenty cold:
Title: Re: The 2018 melting season
Post by: A-Team on April 04, 2018, 03:19:03 PM
Quote
March was plenty cold
But not cold enough to freeze the Arctic Ocean at 82º north of Svalbard which now has open water for the entire year, mid-winter dates of 01 Dec 2017 to 03 Apr 2018 shown in 4 satellite views below (124 days of UH AMSR2, Jaxa-, Ascatsep, Ascatuj).

Had it not been for strong and persistent winds in March that pushed ice towards the Barents Line, the blue ocean event would have been far more extensive in area, not so much northward as zonally because of how Atlantic Waters continue eastward along the continental shelf edge. Modis VIIRS gives an idea of how much more extensive open water would have been with more typical anti-cyclonic winds.

The St Anna Trough will play a key role in somewhat delaying progression of open water past FJL to SZ. There's a good discussion of the oceanographic data there in:

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015JC010804 free full

The Chukchi has some open water for two-thirds of the year, greatly exceeding 'seasonally ice-free' but some of this is icepack lift-off rather than warm water overwhelming ice formation.

We may need to re-examine the notion that the Arctic Ocean will re-freeze in winters after 'blue ocean' summers. That may still be true north of the CAA and for central Arctic Ocean to Siberia but since it's already wrong along above the Barents Line and almost wrong in the Chukchi-Beaufort region, it's hard to see how (inevitable) further warming will bring freeze-over to areas not freezing over now.

Title: Re: The 2018 melting season
Post by: numerobis on April 04, 2018, 03:46:49 PM
The storm forecast on Baffin actually happened: Monday saw strong southeasterly winds (sustained > 50 km/h, gusts > 90 km/h) under generally bright sun with periods of light precipitation, some of it probably rain (hard to tell when it's flying by so fast). The previous two days had seen moderate (40 gusting to 60) northwesterlies over the sea ice (but not much on land, it was quite localized).

Monday's storm came with above-freezing temperatures, and it's been far above normal and is forecast to stay that way for a few days yet with bright sun.

There's been a lot of snow lately by local standards -- about a foot over the Easter weekend, when 5-10cm rates us a snowfall warning.

I see the Baffin ice area bumped up a bit with the northwesterlies (presumably mostly from pushing ice down from the high arctic into the open sea), then fell a bit with the southeasterlies (pushing it back up North, or piling it up against shore).
Title: Re: The 2018 melting season
Post by: Lord M Vader on April 04, 2018, 05:32:52 PM
NEVEN: I'm sorry, but I've to ask... You said in your earlier post that todays century drop (JAXA) is the biggest March drop but it's April now.... Is your statement true for April or was it just so for March 2005-2018?

Sincerely, LMV
Title: Re: The 2018 melting season
Post by: Neven on April 04, 2018, 05:36:46 PM
Sorry, I meant April!  ::)  :-X
Title: Re: The 2018 melting season
Post by: TerryM on April 04, 2018, 06:04:46 PM
A-Team
WoW!


I'm sure that's a first since I've been watching, and probably some millennia longer, (the year round blue water north of Svalbard). Do you think it's atmospheric temperatures, a misguided North Atlantic Drift, an increasingly warm NAD, or an increasingly powerful NAD.


There were photos a few years back of researchers relaxing in bathing suits on the southern shores of Svalbard, but it only lasted a short time.


I recall that last year the WAW's were reported as rising off Newfoundland and disturbing the shallow fish habitat. Could this have pushed so far north?


Terry
Title: Re: The 2018 melting season
Post by: Dharma Rupa on April 04, 2018, 07:06:47 PM
We may need to re-examine the notion that the Arctic Ocean will re-freeze in winters after 'blue ocean' summers. That may still be true north of the CAA and for central Arctic Ocean to Siberia but since it's already wrong along above the Barents Line and almost wrong in the Chukchi-Beaufort region, it's hard to see how (inevitable) further warming will bring freeze-over to areas not freezing over now.

What data do we have on water overturning that far north?  All I've seen recently are some tantalizing buoy data from much further south.
Title: Re: The 2018 melting season
Post by: romett1 on April 04, 2018, 07:18:45 PM
Webpage was down (or didn't update) for some days. Here is Apr 03 vs Mar 29. Images: ftp://ftp-projects.cen.uni-hamburg.de/seaice/AMSR2/
Title: Re: The 2018 melting season
Post by: A-Team on April 04, 2018, 07:19:04 PM
Quote
a first since I've been watching, and probably some millennia longer, (the year round blue water north of Svalbard). Do you think it's atmospheric temperatures, North Atlantic Drift
Right. Not so long ago, the Barents was largely solid ice in mid-winter. Not unreasonably as it is entirely above the Arctic Circle, it is still formally included in the Arctic Ocean by international committee.

That seems bizarre to people coming onto the scene in recent years. The annual 'blue ocean event' is now such a non-event that the goal posts for BOE were moved to the AO proper with few players even noticing. In a few years, they will be moved again to the CAA and Central Arctic. The ice we see in the Barents today has been blown in from the Kara and adjacent Arctic Ocean.

Causation? It's a mix. Mercator Oceans take on surface water temperatures is shown below. The just-above-freezing temperature of sea water has been recolored purple to draw out other areas that are not as drastically warmed as the direct Atlantic Water inflows above Svalbard.

The main anomaly shows the West Spitzbergen Current that runs counter to the East Greenland Current, rounds the corner at the Yermak Plateau and continues east along the shelf break. Note  much more warm water is present at the minimum 15 Sep 2017 than today.

http://bulletin.mercator-ocean.fr/en/PSY4#4/55.68/-64.29

The air temperatures (and rain) are also contributors. The international meteorological station at Ny-Ålesund, Svalbard has excellent long-term records, daily sondes, and rolling window records online.

Quote
What data do we have on water overturning that far north?  All I've seen recently are some tantalizing buoy data from much further south.
The oceanography of the entire area north of Svalbard to Severnaya Zemlya, including the two glacial troughs, has been intensively observed for decades, resulting in perhaps a hundred journal papers in the last seven years including a dozen from N-ICE2015. The 2018 below will help you build a comprehensive set of recent articles.

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2017JC013198
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JC012424
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015JC010804
Title: Re: The 2018 melting season
Post by: uniquorn on April 04, 2018, 07:53:18 PM
The Sea of Okhotsk was one of the big extent fallers yesterday.

Worldview today and Uni-Hamburg amsr2 Jan-Apr3

Title: Re: The 2018 melting season
Post by: bbr2314 on April 04, 2018, 08:14:05 PM
The Sea of Okhotsk was one of the big extent fallers yesterday.

Worldview today and Uni-Hamburg amsr2 Jan-Apr3
As sea-ice becomes increasingly lop-sided into the mid-latitudes during winter, perhaps the melting of the excessive mid-latitude ice during spring results in even more latent heat release than normal -> much more 500MB blocking -> ultimately the high-Arctic ice gets hammered. As we are about to see in Beaufort/Chukchi as Bering's last dregs vanish before our eyes.

May 1, 2018, is going to yield satellite imagery substantially different for both ice cover (record lowest) and snowcover (possible record highest at least in terms of volume) than any other year in the satellite record.
Title: Re: The 2018 melting season
Post by: Dharma Rupa on April 04, 2018, 08:24:28 PM
May 1, 2018, is going to yield satellite imagery substantially different for both ice cover (record lowest) and snowcover (possible record highest at least in terms of volume) than any other year in the satellite record.

Interesting projection, though I have to ponder taking the bet on May 1 snow...Seems to me it is going to go really fast as the Winter cold lets up and allows southern air in.  We can watch the jet stream and see if it will keep the winter snows or flush them.
Title: Re: The 2018 melting season
Post by: avaliablewrongdoer on April 04, 2018, 08:25:08 PM
Hi new person here. Couple of quick questions.

1. When do scientists estimate the arctic will get it's first blue ocean event?

2. Any chance it will be ice free later this year? If yes around what time?

2. When the arctic is free of sea ice for the the first time what kind of global effects will it have on the weather?

<Edit Neven: I've copied your comment to a more appropriate thread (https://forum.arctic-sea-ice.net/index.php/topic,143.msg148552.html#msg148552).>
Title: Re: The 2018 melting season
Post by: uniquorn on April 04, 2018, 08:27:53 PM
Bering may hold out a little longer. The wind has changed again.
Title: Re: The 2018 melting season
Post by: Daniel B. on April 04, 2018, 08:33:37 PM
May 1, 2018, is going to yield satellite imagery substantially different for both ice cover (record lowest) and snowcover (possible record highest at least in terms of volume) than any other year in the satellite record.

Interesting projection, though I have to ponder taking the bet on May 1 snow...Seems to me it is going to go really fast as the Winter cold lets up and allows southern air in.  We can watch the jet stream and see if it will keep the winter snows or flush them.

I am with you.  Although the NA jet stream seems set in place for the next week or so, at this time of year, it will only take a day or two of warm southern winds (or rains) to wipe out much of the snow.  I question the record low also, as the current snow cover is likely to inhibit ice melt - at least for the rest of April.
Title: Re: The 2018 melting season
Post by: A-Team on April 04, 2018, 08:41:53 PM
Please don't post more nonsense on this forum about snow. Include a working url for your snow data and a thickness map and why you believe they are reliable or go to another forum.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 04, 2018, 08:55:01 PM
<snip, we're not going to do a repeat of last year, N.>
Title: Re: The 2018 melting season
Post by: Lord M Vader on April 04, 2018, 09:15:02 PM
Bbr2314: A-Team has posted tons of interesting posts that are very appreciated among many of us! I suggest that the snow get a separate thread in this forum as it is interesting to follow how the snowcover evolves.
Title: Re: The 2018 melting season
Post by: uniquorn on April 04, 2018, 09:35:19 PM
Beaufort Sea Mar29 from 2000-2018. (VIIRS only available for 2018)

Hopefully not too historic to be off topic. Some clouds but good enough for comparison
Title: Re: The 2018 melting season
Post by: A-Team on April 04, 2018, 10:19:05 PM
Yes and thanks for including the map and url that were missing from Reply #235 and the following unsupported (or just intuited) snow-casts from others.

It seems like a real struggle -- despite 1385 members -- to pool individual knowledge of internet resources and collect even the most basic information relevant to the 2018 melt season -- the assorted snow urls, the snow density urls, the melt pond urls, the albedo urls, the cloud urls, the water vapor advection urls, the sea surface temperature urls, the ice surface temperature urls, the radiative transfer urls, the rain urls, the lightning urls, the bottom melt urls, the top melt urls, the side melt urls. 

When multiple semi-independent sources exist, then we need to look at whether they more or less agree and if not, which is the most reliable (just as we do with all the ice thickness urls). Maybe none of them are helpful.

We are mostly not in a position to derive daily values ourselves for any of the above directly from raw satellite data. Less than 0.5% of the participants here look at netCDF data, the main storage medium for climate science (even though those are just a download and double-click in free Panoply). Some of the very best urls don't provide copy-paste graphics because it's assumed you will make your own.

On snow, we've heard a thousand times that it reflects sunlight, provides a thermal blanket, melts out to initiate ponding. True enough, but there's nothing here specific to the 2018 melt season, the same platitudes apply equally well to the 1918, 1818 and 1718 melt seasons.

Yes but how much solar was it reflecting yesterday? Is snow insulation materially affecting heat flow today? Will melt ponds surface tomorrow? How do these compare with the same dates in recent years? That is what it means to follow snow in the 2018 melt season.

From my end, the most interesting url (see up-forum) in the daily snow category provides both thickness and density maps, plus snow surface temperature and salinity. Snow thickness alone does not suffice to determine any of the above snow properties. Snow density etc are not the whole story either but they help. We know that from N-ICE2015 which had simultaneous field work, helicopter and satellite swaths.

I could see someone saying, 'yeah I've looked at all the data, read all the papers, it's all wrong, here's something better, here's data backing up that claim, here's what it means for the rest of 2018 melt season'.

I can't see the slightest interest in 'yeah I can't be bothered with data, journal papers are over my head, physics doesn't apply, it's all wrong anyway, I know all about Arctic Ocean snow from living here in New York, here's something far better, take my word for it: Sept 2025's gonna be all recovered/end of civilization.
Title: Re: The 2018 melting season
Post by: RoxTheGeologist on April 04, 2018, 10:24:57 PM

 ...perhaps the melting of the excessive mid-latitude ice during spring results in even more latent heat release than normal...

Melting snow requires energy to melt, it isn't released. about 330 J/g if memory serves. A good rule of thumb is that breaking bonds requires energy. That's why ocean water temperature gets buffered at its melting point. If it didn't then when melt started it would be a run-away reaction.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 04, 2018, 10:45:42 PM

 ...perhaps the melting of the excessive mid-latitude ice during spring results in even more latent heat release than normal...

Melting snow requires energy to melt, it isn't released. about 330 J/g if memory serves. A good rule of thumb is that breaking bonds requires energy. That's why ocean water temperature gets buffered at its melting point. If it didn't then when melt started it would be a run-away reaction.

Sorry, I should have said melting/formation of ice, as both are occurring simultaneously in spring.
Title: Re: The 2018 melting season
Post by: Niall Dollard on April 04, 2018, 10:56:58 PM

I'm sure that's a first since I've been watching, and probably some millennia longer, (the year round blue water north of Svalbard).

Year round blue water ? I think we would have to wait until circa July 12th this year to confirm that. Maybe it will happen.

Ice though can arrive very late in the spring to the north coast of Spitzbergen (the largest island in Svalbard). Like last year it persisted right on the north coast through May and June. See pic attached for June 21st which shows very close drift ice (red area) right on the coast.

It wasn't until circa July 11th when the last finger of very close drift ice moved off from the NE coast of Sptizbergen. (second pic)

I will agree (as highlighted by A Team) that the area north of Sptizbergen devoid of ice is larger than usual this year. But it isn't unusual to see blue water north of Sptizbergen for today's calendar date (ie April 04). Looking back through the images available on Worldview back to 2012 approximate position of the main ice edge was as follows:

2012 - ice edge 80km north
2013 - 100km north
2014 - 50km north
2015 - 50km north
2016 - 100km north
2017 - ice edge on coast
2018 - 140km north
Title: Re: The 2018 melting season
Post by: crandles on April 05, 2018, 12:03:34 AM
Ice free north of Svalbard. Whole year might be uncommon but occurs from time to time e.g.:

Certainly not as extensive as recently but how about going back to 1985:
http://web.archive.org/web/20100614120551/http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/ARCHIVE/19850404.png

1991 not so much
http://web.archive.org/web/20100614175018/http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/ARCHIVE/19910405.png

1992 shows some sign and 1994 more:
http://web.archive.org/web/20100615134332/http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/ARCHIVE/19940404.png

Title: Re: The 2018 melting season
Post by: uniquorn on April 05, 2018, 12:36:16 AM
North of Svalbard 2017-06-25
Will have to wait a bit longer this year.
Title: Re: The 2018 melting season
Post by: FishOutofWater on April 05, 2018, 06:32:51 AM
NH snow cover is going to rapidly retreat over Asia over the next few weeks as well above normal temperatures melt it away. The sudden stratospheric warming pushed cold air out of the Arctic causing colder than normal temperatures over central and eastern North America, northern Europe and central Asia. That cold air is rapidly retreating over Asia and snow cover will retreat with it. Cool air and snow will stick around in central and eastern Canada while global snow cover makes a rapid retreat to well below normal by the beginning of May.

Spring is coming earlier to the largest continental masses as sloar energy, GHGs and water vapor team up to melt Eurasian snow and warm the atmosphere. The CFSv2 model may be exaggerating this effect some, but it's predicting what we're going to see this month.

In May, it is going to be warmer than normal in the CAA and Alaska melting the snow out earlier than normal. The CFS model isn't perfect but it's getting the climate trend we've been seeing for the past decade right.

The key to the CFS forecast as to what happens to sea ice for the next 3 months is high pressure over the Arctic ocean. That means greater than average solar energy hitting the ice.

NH snow extent at the end of March isn't indicative of NH summer conditions. Snow cover at the end of April and May is much more indicative. I see no evidence that last spring's heavy snow cover in late May will be repeated this year with the possible exception of eastern Canada.
Title: Re: The 2018 melting season
Post by: litesong on April 05, 2018, 08:07:43 PM
Melting snow requires energy to melt, it isn't released. about 330 J/g if memory serves. A good rule of thumb is that breaking bonds requires energy. That's why ocean water temperature gets buffered at its melting point. If it didn't then when melt started it would be a run-away reaction.
  That's why the North Pole acts as a weather attenuator...... at least for a while. From another thread:
Average Arctic sea ice VOLUME for April 1, for the period 1980-89, was ~ 30,200 cubic kilometers. April 1, 2018 Arctic sea ice VOLUME is ~ 21,900 cubic kilometers, ~ 8300 cubic kilometers LESS than the 1980-89 average for April 1. Through the course of the latter years, monthly Arctic sea ice volumes have ranged from  ~ 7000 to 12,000 cubic kilometers  below 1980's decade average, despite half a century of languid solar TSI energies, including 11+ years of low solar TSI(including a 3+ year period setting a 100 year record low).
////////
The energy needed to melt 8300 cubic kilometers of ice is......... ~ 25 to 26 times the annual energy consumption of the U.S. All this energy does NOT add temperature increase to the Arctic. Once ice-free conditions exist in the Arctic, any other added energy WILL raise Arctic water volume temperatures. About sixty times the volume of melted Arctic ice in the form of water will then be affected by any excess energy.
Title: Re: The 2018 melting season
Post by: uniquorn on April 05, 2018, 11:58:24 PM
That looks like a bit of refreeze along some of the chukchi coast today

Worldview TM
Title: Re: The 2018 melting season
Post by: LRC1962 on April 06, 2018, 07:32:04 AM
All this energy does NOT add temperature increase to the Arctic. Once ice-free conditions exist in the Arctic, any other added energy WILL raise Arctic water volume temperatures. About sixty times the volume of melted Arctic ice in the form of water will then be affected by any excess energy.
There is a dynamic that tends to be left out. That is the jet stream. Pre 2000 the jet stream usually was a buffer between weather systems in the Arctic and the rest of the NH. Now more often then not it is the main engine that is either pushing heat into it or pulling cold out of it. This means that whereas pre 2000 the sun was the biggest factor of heat for the Arctic, now location of the jet stream is by far the biggest factor.
As example how many times in the last few years have areas in the Arctic gotten close to or above 0C in the dead of winter? Or conversely when we have had the warmest global temps on record in the summer, the Arctic has had a hard time melting? If you check what the jet stream is doing you will see that it is a very important factor . If the wondering stream ever hit the Arctic in the summer like it has in the winter in the last few years, a great melt would occur regardless of sun.
Title: Re: The 2018 melting season
Post by: uniquorn on April 06, 2018, 10:33:48 AM
The sea of okhotsk bringing extent down.
Title: Re: The 2018 melting season
Post by: JayW on April 06, 2018, 12:21:51 PM
125 hour loop of the Chukchi region.  March 31-April 5.  Easterly winds appear to be in charge for 2-3 more days over this and the Beaufort region.  I'll do the Beaufort after a couple more days of easterly wind, it'll be more interesting.

I tried boosting the contrast to bring out the details.

http://feeder.gina.alaska.edu/npp-gina-alaska-truecolor-images?search%5Bfeeds%5D%5B5%5D=1&search%5Bsensors%5D%5B3%5D=1

Title: Re: The 2018 melting season
Post by: oren on April 06, 2018, 12:59:35 PM
Thank you JayW. Beautiful animation.
It is still cold enough for new ice to form over the exposed water in the Chukchi. When that changes, we will get sharp extent drops of all this thin new ice.
Title: Re: The 2018 melting season
Post by: Neven on April 06, 2018, 02:33:45 PM
My goodness, so early.
Title: Re: The 2018 melting season
Post by: jdallen on April 06, 2018, 06:38:14 PM
My goodness, so early.
4-6 weeks early by my estimate, and what I feared would happen.
Title: Re: The 2018 melting season
Post by: numerobis on April 06, 2018, 06:50:26 PM
Anecdote: the snow and ice is melting off the roads in Iqaluit a month earlier than last year.
Title: Re: The 2018 melting season
Post by: litesong on April 06, 2018, 09:19:06 PM
All this energy does NOT add temperature increase to the Arctic. Once ice-free conditions exist in the Arctic, any other added energy WILL raise Arctic water volume temperatures. About sixty times the volume of melted Arctic ice in the form of water will then be affected by any excess energy.
There is a dynamic that tends to be left out. That is the jet stream. Pre 2000 the jet stream usually was a buffer between weather systems in the Arctic and the rest of the NH. Now more often then not it is the main engine that is either pushing heat into it or pulling cold out of it. This means that whereas pre 2000 the sun was the biggest factor of heat for the Arctic, now location of the jet stream is by far the biggest factor.
Lots of people have said the same. It may be true. However continuous Present High Arctic over-temperatures (PHAB 8) s or FAB 8) s) have been increasing since the latter 1950's & early 60's, when continuous over-temperatures were ~ 30 to 40 straight days. Then FAB 8) s rose to 90  straight days, 100+ straight days, & 140 straight days. From latter 2016 thru early 2017, FAB 8)(1) sizzled for 230+ straight days. 2017 spring & summertime direct solar heat, which has been languid for half century(+?), & low for 11+ years(including 3+ year period setting a 100 year record low), dropped High Arctic temperatures below average. During the latter 2017 to early 2018 period, with the sun below the horizon, & once more AGW effects became prominent, FAB 8)(2) lasted for 215+ continuous days.
These long continuous days of over-temperatures are more than just the effects of a wavering jet stream. When the sun is below the horizon, AGW effects become more evident in the High Arctic.... on a continuing basis.   
Title: Re: The 2018 melting season
Post by: Sebastian Jones on April 06, 2018, 09:35:38 PM
Anecdote: the snow and ice is melting off the roads in Iqaluit a month earlier than last year.
We are about normal at Dawson City Yukon. The river is still drivable. Almost time to start our annual breakup watch.
http://yukonriverbreakup.com/ (http://yukonriverbreakup.com/)
Title: Re: The 2018 melting season
Post by: Dharma Rupa on April 06, 2018, 10:55:30 PM
My goodness, so early.
4-6 weeks early by my estimate, and what I feared would happen.

Watch for clear skies.  This might be the year, although I still say it could decide to melt out in the middle of Winter just as well.  The air is the driver of variability.  The ocean is the driver of melt.
Title: Re: The 2018 melting season
Post by: subgeometer on April 07, 2018, 04:38:01 AM
The mush being flushed around the southern Chukchi sea from April 1-6, under clear skies. If high pressure hangs around things are going to get bad fast
Title: Re: The 2018 melting season
Post by: Gray-Wolf on April 07, 2018, 12:28:54 PM
As I see things by May 1st in all the years since 2013 we've been able to call off a perfect melt storm due to conditions through late March/April.

If the forecasts hold then this year we will still be on the path for one with widespread HP across the basin and occasional lows over the Baltic side of things allowing a northerly flow through Fram.

Of course if we saw a 2007 or a 2012 the ice would be struggling by late July.
Title: Re: The 2018 melting season
Post by: uniquorn on April 07, 2018, 04:14:25 PM
Kara Sea has largely avoided this years warm weather events but, as highlighted by Neven up thread, is getting some more challenging weather today and tomorrow.

Worldview terra modis apr5 (last clear day)
Nullschool forecast.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 07, 2018, 06:40:47 PM
We broke the graph again :)

(https://ccin.ca/home/sites/default/files/snow/snow_tracker/na_swe.png)

(https://ccin.ca/home/sites/default/files/snow/snow_tracker/plot_anom_sdep.png)
Title: Re: The 2018 melting season
Post by: JayW on April 08, 2018, 04:03:39 AM
103 hour loop of the Beaufort Sea region, April 3-7, 2018.

http://feeder.gina.alaska.edu/npp-gina-alaska-truecolor-images?page=3&search%5Bfeeds%5D%5B5%5D=1&search%5Bsensors%5D%5B3%5D=1

Second attachment is the ECMWF 96 hour wind forecast showing easterly winds persisting north of Alaska for a few more days.

https://weather.us/model-charts/euro/north-pole/temperature-f/20180408-0300z.html
Title: Re: The 2018 melting season
Post by: romett1 on April 08, 2018, 11:53:09 AM
Average sea ice area for Bering Sea so far in April is just 89,000 km² (NSIDC, 5-day trailing average). There is small rebound on the chart, but question about the quality of that ice. Image: https://sites.google.com/site/arctischepinguin/home/amsr2/grf
Title: Re: The 2018 melting season
Post by: uniquorn on April 08, 2018, 02:56:19 PM
A closer look at Mackenzie Bay, Beaufort Sea yesterday. A nice example of refreeze and ridging. Temperature ~-19C

Worldview Terra/Modis
Title: Re: The 2018 melting season
Post by: Archimid on April 08, 2018, 03:37:42 PM
Several examples of refreezing in the Bering Sea.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 08, 2018, 09:11:40 PM
I am floored that this graph's rise has only continued.

This has happened concurrent with the Bering Sea melt. The next several days should be adequate for even MORE growth.

Models are beginning to show a pattern that could constitute a "breakdown" by D7, but it seems fairly tentative.

(https://ccin.ca/home/sites/default/files/snow/snow_tracker/na_swe.png)

In any case, with so much mass accumulated so late in the year, I believe that large areas of +albedo anomalies at relatively low latitudes will act in tandem with the deficiency of sea ice in Bering/Barentz to vacuum large quantities of oceanic heat content into the high Arctic. This likely paves the way for sustained losses through the rest of this month in both aforementioned locations, spreading into Chukchi and Beaufort as well.

(https://ccin.ca/home/sites/default/files/snow/snow_tracker/plot_anom_sdep.png)
Title: Re: The 2018 melting season
Post by: Lord M Vader on April 08, 2018, 09:51:37 PM
The melting of all that excess snow should start in 1-2 days and go down fairly quickly.
Title: Re: The 2018 melting season
Post by: ghoti on April 08, 2018, 10:38:04 PM
Meanwhile today NASA Operation Icebridge posted Facebook photos of the Yukon River showing very little snow on the land. So much for high albedo.

Title: Re: The 2018 melting season
Post by: bbr2314 on April 08, 2018, 11:29:32 PM
The melting of all that excess snow should start in 1-2 days and go down fairly quickly.
I disagree. The same was said 30 days ago. We shall see. I think drops will start in North America by the 15th but won't pick up steam until the end of the month. Eurasia's warming should be more sustained, however.
Title: Re: The 2018 melting season
Post by: Thomas Barlow on April 09, 2018, 04:16:08 AM
Ding !
Lowest extent for date. That sneaked up on me.
http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Title: Re: The 2018 melting season
Post by: FishOutofWater on April 09, 2018, 03:51:10 PM
Models show a much warmer than normal 10 days in northern Europe ahead but most of the snowy areas in North America will remain colder than normal. Expect negative snow anomalies in Eurasia to increase but positive anomalies in north America to continue.
Title: Re: The 2018 melting season
Post by: uniquorn on April 09, 2018, 09:34:49 PM
Yes, nullschool forecasting winds over 5C close to Svalbard on apr13.

Update on Kara Sea. Apr5-9 (worldview)
Title: Re: The 2018 melting season
Post by: numerobis on April 09, 2018, 10:15:23 PM
What's the verdict on GFS vs ECMWF?

I thought euro was generally more accurate (it's certainly my experience in Iqaluit that ECMWF is eerie at times), but I see mostly GFS being used here.
Title: Re: The 2018 melting season
Post by: Neven on April 09, 2018, 11:24:20 PM
My impression is that ECMWF is better. I only use GFS for temperature and some other stuff on Climate Reanalyzer.
Title: Re: The 2018 melting season
Post by: Niall Dollard on April 10, 2018, 12:45:23 AM
Here are charts (courtesy weatherdotus) for 13 April at 12am from US Global and Euro. Broadly quite similar but US has that extra hot spot to the west of Svalbard.

The hot spot is also over the same area where Nullschool displays persistently high SSTs (derived from NCEP RTG SST). I have not come across any evidence to back up the very high SSTs (often as high as 15 C) constantly displayed in that area on Nullschool.
Title: Re: The 2018 melting season
Post by: uniquorn on April 10, 2018, 01:32:28 AM
What's the verdict on GFS vs ECMWF?
I see your point. I picked a random spot but selecting a few locations nearby I get 3.6C to 6.4C just now.
Title: Re: The 2018 melting season
Post by: FishOutofWater on April 10, 2018, 05:13:49 AM
I think that the ECMWF is better at forecasting the behavior of blocking highs which tend to give all models trouble. Over the last 2 years blocking highs have brought unprecedented heat to the Arctic in the dark months. The ECMWF has a tendency to overforecast low pressure depth in the Arctic.

The GFS has been propagating waves at slightly higher speeds than the ECMWF recently. Thus the GFS predicted rain storms 4 days ahead that came a day later in the eastern U.S. The ECMWF has done a better job of forecasting our storms for the past month. In general it's a better model, but neither model is close to perfect.

The problem with the ECMWF is access to output. The GFS has far more data freely available to the public.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 10, 2018, 05:19:43 AM
I think that the ECMWF is better at forecasting the behavior of blocking highs which tend to give all models trouble. Over the last 2 years blocking highs have brought unprecedented heat to the Arctic in the dark months. The ECMWF has a tendency to overforecast low pressure depth in the Arctic.

The GFS has been propagating waves at slightly higher speeds than the ECMWF recently. Thus the GFS predicted rain storms 4 days ahead that came a day later in the eastern U.S. The ECMWF has done a better job of forecasting our storms for the past month. In general it's a better model, but neither model is close to perfect.

The problem with the ECMWF is access to output. The GFS has far more data freely available to the public.

ECMWF data is almost as accessible if you know where to look.

The GFS suffers from poor run to run continuity because its snow-ice-melt dynamics are incredibly poor. The Canadian is the best model in this regard (no surprise, bc Canada). The ECMWF is in between.

But the models' abilities to resolve snowfall and ice melt/formation during their runs is extremely poor and one of the main reasons the GFS is so terrible.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 10, 2018, 06:03:13 AM
...!
Title: Re: The 2018 melting season
Post by: Niall Dollard on April 10, 2018, 09:01:24 AM
What's the verdict on GFS vs ECMWF?

I see your point. I picked a random spot but selecting a few locations nearby I get 3.6C to 6.4C just now.
Uniquorn
Here is the link to the thread previously discusoing the high SSTs in the area you are referring to :
https://forum.arctic-sea-ice.net/index.php/topic,2194.msg134595.html#msg134595
Title: Re: The 2018 melting season
Post by: be cause on April 10, 2018, 09:29:02 AM
As this is the place for speculation and snow .. I can report that all snow in N. Ireland has melted but .. !  .. there is 2 days of snow forecast before the end of the month . I could post this in the N. Hemisphere snow cover thread .. but that is obviously the wrong place .. b.c.
Title: Re: The 2018 melting season
Post by: romett1 on April 10, 2018, 09:33:13 AM
Rough weather for Bering Strait and Bering Sea for the next 5 days, winds are from north.
Image: http://cci-reanalyzer.org/
Title: Re: The 2018 melting season
Post by: Jim Hunt on April 10, 2018, 12:00:38 PM
ECMWF data is almost as accessible if you know where to look.

Where do you suggest for "operational" ECMWF data?

For reanalysis data see:

https://forum.arctic-sea-ice.net/index.php/topic,1871.msg149314.html#msg149314
Title: Re: The 2018 melting season
Post by: uniquorn on April 10, 2018, 02:32:50 PM
Thanks Niall.
windytv displays ecmwf and gfs.
https://www.windy.com/?temp,76.568,14.854,4,m:fOAagpe
Title: Re: The 2018 melting season
Post by: Thomas Barlow on April 10, 2018, 04:12:33 PM
As this is the place for speculation and snow .. I can report that all snow in N. Ireland has melted but .. !  .. there is 2 days of snow forecast before the end of the month . I could post this in the N. Hemisphere snow cover thread .. but that is obviously the wrong place .. b.c.

We are having some of the best late skiing in years in Vermont.
https://www.trappfamily.com/activities.htm

This relates to Arctic Sea Ice melt, because as the Arctic is warmer, the jet stream is wavier, and by luck it tends to keep our area cool enough, with snow going pretty well. We'll be skiing every day for weeks at this point  We are well above average snow on our highest mountain for this time of year.
http://www.matthewparrilla.com/mansfield-stake/

The way the Arctic affects this area is fascinating, winds sometimes blowing straight from the Arctic and Hudson Bay, sometimes across the iceberg-laden Baffin Bay.

It will be interesting to see what happens around here in summer when Lincoln, Nares might be melted out, and north of the CAA. Maybe for the first time in ... centuries? Open water from Fram to Beaufort and Nares a possibility this year , or next?
Title: Re: The 2018 melting season
Post by: bbr2314 on April 10, 2018, 05:07:48 PM
ECMWF data is almost as accessible if you know where to look.

Where do you suggest for "operational" ECMWF data?

For reanalysis data see:

https://forum.arctic-sea-ice.net/index.php/topic,1871.msg149314.html#msg149314

I go here and adjust settings accordingly:

https://weather.us/model-charts/euro/massachusetts/gusts-3h-mph/20171030-0600z.html
Title: Re: The 2018 melting season
Post by: numerobis on April 10, 2018, 06:28:07 PM
Windy has ECMWF, but you can’t see high latitudes well because of the projection.

GFS frequently tells me there’ll be no wind, and we get strong winds instead.

The Canadian model doesn’t seem to be as good as the euro when it comes to topography. It’ll forecast strong winds from the NE and we’ll get nothing — because Iqaluit is mostly in a valley oriented perpendicular to that. Might be an accident of grid size, or even of grid position.
Title: Re: The 2018 melting season
Post by: uniquorn on April 10, 2018, 07:03:07 PM
Windy has ECMWF, but you can’t see high latitudes well because of the projection.
windy has a 3d mode in the menu
Title: Re: The 2018 melting season
Post by: uniquorn on April 10, 2018, 09:44:32 PM
Kara forked tongue. Ascat day40-98

Technical note:
ImageJ: adjusted brightness/contrast 23-255 (some loss), CLAHE 127-256-2.2
gimp: duplicate final frame, scale 200%, sharpen 60
thanks to A-team for tips on ascat graphics

Title: Re: The 2018 melting season
Post by: Neven on April 10, 2018, 10:54:19 PM
For ECMWF SLP I like to check Tropical Tidbits (https://www.tropicaltidbits.com/analysis/models/?model=ecmwf&region=nhem&pkg=z500_mslp&runtime=2018041012&fh=24), but I still look at Wetterzentrale as well (on the ASIG Forecasts page (https://sites.google.com/site/arcticseaicegraphs/forecasts), where the Climate Reanalyzer GFS SAT etc is as well).
Title: Re: The 2018 melting season
Post by: Lord M Vader on April 11, 2018, 08:36:28 AM
Interesting to see whether that thick ice northeast of Severnaya Zemlya is going to reach the "Death Zone" this season or if it's going to stay in the Arctic basin.

We shall see!
Title: Re: The 2018 melting season
Post by: S.Pansa on April 11, 2018, 12:50:47 PM
bbr2314 has already mentioned it, but for the sake of completeness: here (https://weather.us/model-charts/euro/north-pole/temperature-f/20180411-1200z.html) the direct link to the ECMFW forecast for the North Pole from weather.us. I am not aware of any other site that offers so many different parameters for the ECMFW-model (under parameters obviously): 2m, 925, 850, 500 mbar Air temps, snow depth, Due point, different wind speeds, cloud cover, heat flux, air pollution, etc).
Another neat feature is the easy way to compare different models, not just GFS(US), but also
CAN and AUS.
 
It is also available for other languages, amongst them german (https://kachelmannwetter.com/de) (advantage, temps are in Celsius).
By way of example:

Title: Re: The 2018 melting season
Post by: Jim Hunt on April 11, 2018, 01:20:21 PM
There were clear skies over the Mackenzie Delta yesterday, revealing some open(ish) areas in the Beaufort Sea:

http://GreatWhiteCon.info/2018/04/facts-about-the-arctic-in-april-2018/#Apr-11

Only the merest hint of a blip on the area graph so far though:
Title: Re: The 2018 melting season
Post by: magnamentis on April 11, 2018, 06:02:05 PM
Windy has ECMWF, but you can’t see high latitudes well because of the projection.

GFS frequently tells me there’ll be no wind, and we get strong winds instead.

The Canadian model doesn’t seem to be as good as the euro when it comes to topography. It’ll forecast strong winds from the NE and we’ll get nothing — because Iqaluit is mostly in a valley oriented perpendicular to that. Might be an accident of grid size, or even of grid position.

doesn't windy give a choice between 4 or 5 sources? perhaps i mix this up but see the shot  below
Title: Re: The 2018 melting season
Post by: El Cid on April 12, 2018, 01:42:07 PM
Based on NCEP data+gisstemp estimates, the past 3 winters have been the warmest on the arctic by far. I think this tells us much more about the state of the ice than any models. If the ice is thinner, more fractured, the temperatures are higher I guess. So this ice is likely not in a very good state
Title: Re: The 2018 melting season
Post by: Daniel B. on April 12, 2018, 04:27:58 PM
Yes, and the ice has responded with the lowest maxima.  However, the past summers have not been the warmest.  The warmest summers have been, not surprisingly, 2007, 11, and 12 (2016 was the fourth warmest).  These correspond to the lowest ice minima.  Since the turn of the century, the coolest summers have been 2014, 17, and 13, which showed in higher ice minima.  The warmest spring (AMJ) occurring in 2010, which resulted in the largest annual ice loss, but the temperatures cooled in July, slowing the remaining ice loss.

http://sites.uci.edu/zlabe/arctic-temperatures/ (http://sites.uci.edu/zlabe/arctic-temperatures/)
Title: Re: The 2018 melting season
Post by: FrostKing70 on April 12, 2018, 05:36:24 PM
El Cid,

What is the scale on the right?
Title: Re: The 2018 melting season
Post by: romett1 on April 12, 2018, 06:10:30 PM
Not the best news for Bering Sea and Chukchi Sea - after strong northern winds (until Saturday) earth.nullschool shows strong southern winds starting around Sunday, bringing temperatures above 0 °C and lasting for several days (until Wednesday at least). Bering Sea and Chukchi Sea - Apr 09 - Apr 11, Worldview.
Title: Re: The 2018 melting season
Post by: josh-j on April 12, 2018, 06:19:50 PM
Since the turn of the century, the coolest summers have been 2014, 17, and 13, which showed in higher ice minima.

Excuse me for sticking my nose in here, but the monthly temperature rankings at Zach's site look more like showing that 2000 had the coolest summer this century so far. Undoubtedly a bit of a cooler reoccurrence recently but nevertheless..
Title: Re: The 2018 melting season
Post by: 6roucho on April 12, 2018, 06:50:14 PM
Wasn’t 2000 in the 20th century?
Title: Re: The 2018 melting season
Post by: Daniel B. on April 12, 2018, 06:52:52 PM
Wasn’t 2000 in the 20th century?

Yes, it was.
Title: Re: The 2018 melting season
Post by: josh-j on April 12, 2018, 11:34:50 PM
Wasn’t 2000 in the 20th century?

D'oh!  ::) Carry on!  :-X

Edit: Apologies, Dan B.
Title: Re: The 2018 melting season
Post by: litesong on April 13, 2018, 01:26:05 AM
Since the turn of the century, the coolest summers have been 2014, 17, and 13, which showed in higher ice minima.
AGW denier daniel likes to hide behind the solar TSI, which has been languid for half a century, & low for 11+ years(including a 3+ year solar TSI low setting a 100 year record). With the 24 hours of sunlight(yet low TSI) on the High Arctic, sure there are cool summers. AGW denier daniel doesn't mention low TSI, which if not for AGW GHG energy increases, could have lead to a continuous decade of low High Arctic summer temperatures.
Title: Re: The 2018 melting season
Post by: kiwichick16 on April 13, 2018, 01:47:39 AM
Thanks  el cid  @  #300   

That graph must have a significant trend line
Title: Re: The 2018 melting season
Post by: Daniel B. on April 13, 2018, 04:04:02 AM
Since the turn of the century, the coolest summers have been 2014, 17, and 13, which showed in higher ice minima.
AGW denier daniel likes to hide behind the solar TSI, which has been languid for half a century, & low for 11+ years(including a 3+ year solar TSI low setting a 100 year record). With the 24 hours of sunlight(yet low TSI) on the High Arctic, sure there are cool summers. AGW denier daniel doesn't mention low TSI, which if not for AGW GHG energy increases, could have lead to a continuous decade of low High Arctic summer temperatures.

Your last post was rather confusing.  Are you claiming that low TSI was or was not responsible for the cooler summers?  Or are you just denying that the summers were cooler?  Or are you just spurting nonsense and name calling, because you have no clue?
Title: Re: The 2018 melting season
Post by: Wherestheice on April 13, 2018, 04:37:14 AM
Since the turn of the century, the coolest summers have been 2014, 17, and 13, which showed in higher ice minima.
AGW denier daniel likes to hide behind the solar TSI, which has been languid for half a century, & low for 11+ years(including a 3+ year solar TSI low setting a 100 year record). With the 24 hours of sunlight(yet low TSI) on the High Arctic, sure there are cool summers. AGW denier daniel doesn't mention low TSI, which if not for AGW GHG energy increases, could have lead to a continuous decade of low High Arctic summer temperatures.


I too sense some denial with Daniel B. but this is off topic. Sp lets keep on topic.
Title: Re: The 2018 melting season
Post by: litesong on April 13, 2018, 08:43:35 AM
I too sense some denial with Daniel B. but this is off topic. Sp lets keep on topic.
Read more of AGW denier daniel, & you will know he is an AGW denier. If AGW deniers post in error, no post to oppose their error is off-topic.
Title: Re: The 2018 melting season
Post by: Coffee Drinker on April 13, 2018, 09:29:16 AM
Since the turn of the century, the coolest summers have been 2014, 17, and 13, which showed in higher ice minima.
AGW denier daniel likes to hide behind the solar TSI, which has been languid for half a century, & low for 11+ years(including a 3+ year solar TSI low setting a 100 year record). With the 24 hours of sunlight(yet low TSI) on the High Arctic, sure there are cool summers. AGW denier daniel doesn't mention low TSI, which if not for AGW GHG energy increases, could have lead to a continuous decade of low High Arctic summer temperatures.

Can you please explain what you mean? The weak sun is responsible for colder arctic summers?
Title: Re: The 2018 melting season
Post by: El Cid on April 13, 2018, 09:59:40 AM
El Cid,

What is the scale on the right?

The left scale is DJF average temp north of 60, in degree C.
Title: Re: The 2018 melting season
Post by: colchonero on April 13, 2018, 01:08:12 PM
I too sense some denial with Daniel B. but this is off topic. So lets keep on topic.
Read more of AGW denier daniel, & you will know he is an AGW denier. If AGW deniers post in error, no post to oppose their error is off-topic.

Ok, he is a denier so what? It's just his current opinion. It might be wrong or ignorant from your perspective, but we are all wrong 'bout something. You don't have to refer to him like that everytime you mention his name and rub it in everybody's face. I mean you can of course if you want, it's free speech, it just sounds  so stupid and weird when you write it multiple times in a single comment every time you mention him, and it's not his name nor his profession, it's just his temporary position, that he can change as soon as tomorrow. We can actually get it if you write it once. It makes no sense to write it multiple times. It'd be like when you go to buy to something, to refer to the guy working there "hey you global warming denier/alarmist John give me 2 pounds of burger meat" or to tell other people like "there is this Lakers' fan Mike at the food court, he sells pizza and pasta, and this Lakers' fan Mike has damn good prices". What do you think how would people look at you??


Now on topic. Not much changes from past couple of days. Both GFS and ECMWF see HP over the central basin, with positive anomalies, over parts of the Arctic. Highest anomalies forecasted on the Russian side and the central Arctic.  CAA, coastal Beaufort, and Atlantic side, Kara sea etc. on the other hand should remain about or below average
Title: Re: The 2018 melting season
Post by: Neven on April 13, 2018, 01:50:21 PM
I agree with colchonero.
Title: Re: The 2018 melting season
Post by: dosibl on April 13, 2018, 03:19:16 PM
The Bering sea is quickly racking up warming anomaly, last season set a record of ~160 MJ/m2 by the end of June, this season is on pace to double that. My understanding of this data is that it doesn't account for cloud cover (hence the 'potential'), but its another metric into the unusual season on that side of the world.

https://sites.google.com/site/cryospherecomputing/warming-potential/graphs
Title: Re: The 2018 melting season
Post by: RoxTheGeologist on April 13, 2018, 04:41:55 PM
The Bering sea is quickly racking up warming anomaly, last season set a record of ~160 MJ/m2 by the end of June, this season is on pace to double that. My understanding of this data is that it doesn't account for cloud cover (hence the 'potential'), but its another metric into the unusual season on that side of the world.

https://sites.google.com/site/cryospherecomputing/warming-potential/graphs

At 334 J/g to melt ice, that's an extra 479Kg/m2 of melt potential, or about 0.52m of ice melt.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 13, 2018, 06:06:09 PM
The Bering sea is quickly racking up warming anomaly, last season set a record of ~160 MJ/m2 by the end of June, this season is on pace to double that. My understanding of this data is that it doesn't account for cloud cover (hence the 'potential'), but its another metric into the unusual season on that side of the world.

https://sites.google.com/site/cryospherecomputing/warming-potential/graphs

At 334 J/g to melt ice, that's an extra 479Kg/m2 of melt potential, or about 0.52m of ice melt.

Combined with an (IMO) likely impending weak to (more likely) moderate El Nino, I suspect the max for 18-19 in the Bering will be under 100K KM^2 extent. The additional potential energy accumulated this winter/spring is likely sufficient to flip the sea forever, the ice that formed this yr was generally .5M or less in thickness which is why it was obliterated so quickly.

Title: Re: The 2018 melting season
Post by: jdallen on April 13, 2018, 06:38:30 PM
 I've been pondering the Bering for a while now this season.  The change in potential is like giving a "kick" to a pendulum, which has less meaningful impact now, but unknown but possibly dangerous ones later in the season.

I have three questions I will be trying to answer as we continue.
1) How will this heat and early open extent affect weather.
2) How much will escape to the Chukchi and how soon.
3) What cascade may take place as a result of the first two events.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 13, 2018, 06:42:18 PM
I've been pondering the Bering for a while now this season.  The change in potential is like giving a "kick" to a pendulum, which has less meaningful impact now, but unknown but possibly dangerous ones later in the season.

I have three questions I will be trying to answer as we continue.
1) How will this heat and early open extent affect weather.
2) How much will escape to the Chukchi and how soon.
3) What cascade may take place as a result of the first two events.

Title: Re: The 2018 melting season
Post by: jdallen on April 13, 2018, 07:03:54 PM
I don't think the open water in the Bering is the source of the heat generating anomalies further north. I don't think it has enough heat to do that.  I think the actual source of heat has been the huge volumes of moisture that have swept north by storms.

The heat in the Bering at this juncture is just grease on the skids.  When SSTs climb above 0 is when direct effects of heat in the Bering will come into play.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 13, 2018, 07:13:59 PM
I don't think the open water in the Bering is the source of the heat generating anomalies further north. I don't think it has enough heat to do that.  I think the actual source of heat has been the huge volumes of moisture that have swept north by storms.

The heat in the Bering at this juncture is just grease on the skids.  When SSTs climb above 0 is when direct effects of heat in the Bering will come into play.
I don't know about that. The anomalies further north could be a result of the accumulated heat content over the past 365 days / Pacific salinity intrusion. This is directly due to Bering's increasingly early melt -> enhanced transport of Pac heat into the Chukchi/Beaufort. But you are also probably partially / mostly correct in asserting that the storms have also been a major source of heat. 
Title: Re: The 2018 melting season
Post by: Ken Feldman on April 13, 2018, 07:38:48 PM
I've been pondering the Bering for a while now this season.  The change in potential is like giving a "kick" to a pendulum, which has less meaningful impact now, but unknown but possibly dangerous ones later in the season.

I have three questions I will be trying to answer as we continue.
1) How will this heat and early open extent affect weather.
2) How much will escape to the Chukchi and how soon.
3) What cascade may take place as a result of the first two events.

Some basic info about flow of water from the Bering Sea to the Arctic in this presentation:

http://psc.apl.washington.edu/HLD/Bstrait/Woodgate_AONSeattleNov2015_17thNov2015.pdf (http://psc.apl.washington.edu/HLD/Bstrait/Woodgate_AONSeattleNov2015_17thNov2015.pdf)

The linked presentation provides the results of 25 years (1990 to 2015) of monitoring flows through the Bering Strait.  Flows from the Pacific into the Arctic are on the order of about 1 Sv which is 1/3 to 1/5 the average flows across the Fram Strait.  The strait is usually ice covered from January through April, so the area opened a little earlier this year, but still has some ice in it.  I'm not sure this is going to have a large impact on the rest of the melt season.  I think, as 2007 and 2012, it will come down to the May melt ponds and the amount of ice exported across the Fram.

Here's a paper on the southern Bering Sea:  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5619787/ (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5619787/)

It's seasonally ice covered as described below:

Quote
The eastern Bering Sea is ice-free during the summer and much of the fall. Sea ice usually begins to form on the northern shelf in December, with strong, frigid northerly winds both opening polynyas where sea ice forms and advecting the ice southward [5]. The leading edge melts, cooling and freshening the water column. Typically, ice appears on the southern shelf in January, reaches a maximum in February or March, and is gone by mid-May [6]. In cold years, sea ice advances more than 1000 km from the Bering Strait (66°N) to the Alaskan Peninsula, while in warmer years, ice remains north of 58°N.

Historically, the southeastern Bering Sea has been characterized by high year-to-year variability in sea-ice extent in March and April [7]. This high variability was interrupted in 2001 by a five-year period of low (almost nonexistent on the southern shelf) sea-ice extent and warm ocean temperatures (2001–2005). To improve understanding of how long-term warming can impact this ecosystem, a major study (Bering Sea Project, http://www.nprb.org/bering-sea-project) was designed to explore this ecosystem from 2007 to 2010. Because of the historical record of high inter-annual variability, it was expected that at least one of the project years would also support warmer (less sea ice) conditions. Unfortunately for the Bering Sea Project, the warm period of 2001–2005 was followed by a period of extensive sea ice during spring and cold ocean temperatures over the entire eastern shelf (2007–2012) [7,8]. During the intermediate year, 2006, some ice was observed on the southern shelf and ocean temperatures were near normal.
 
Title: Re: The 2018 melting season
Post by: Dharma Rupa on April 13, 2018, 07:43:47 PM
I don't think the open water in the Bering is the source of the heat generating anomalies further north. I don't think it has enough heat to do that.  I think the actual source of heat has been the huge volumes of moisture that have swept north by storms.

The heat in the Bering at this juncture is just grease on the skids.  When SSTs climb above 0 is when direct effects of heat in the Bering will come into play.

You think maybe the Arctic is no longer a desert?
Title: Re: The 2018 melting season
Post by: bbr2314 on April 13, 2018, 07:54:51 PM
I've been pondering the Bering for a while now this season.  The change in potential is like giving a "kick" to a pendulum, which has less meaningful impact now, but unknown but possibly dangerous ones later in the season.

I have three questions I will be trying to answer as we continue.
1) How will this heat and early open extent affect weather.
2) How much will escape to the Chukchi and how soon.
3) What cascade may take place as a result of the first two events.

Some basic info about flow of water from the Bering Sea to the Arctic in this presentation:

http://psc.apl.washington.edu/HLD/Bstrait/Woodgate_AONSeattleNov2015_17thNov2015.pdf (http://psc.apl.washington.edu/HLD/Bstrait/Woodgate_AONSeattleNov2015_17thNov2015.pdf)

The linked presentation provides the results of 25 years (1990 to 2015) of monitoring flows through the Bering Strait.  Flows from the Pacific into the Arctic are on the order of about 1 Sv which is 1/3 to 1/5 the average flows across the Fram Strait.  The strait is usually ice covered from January through April, so the area opened a little earlier this year, but still has some ice in it.  I'm not sure this is going to have a large impact on the rest of the melt season.  I think, as 2007 and 2012, it will come down to the May melt ponds and the amount of ice exported across the Fram.

Here's a paper on the southern Bering Sea:  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5619787/ (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5619787/)

It's seasonally ice covered as described below:

Quote
The eastern Bering Sea is ice-free during the summer and much of the fall. Sea ice usually begins to form on the northern shelf in December, with strong, frigid northerly winds both opening polynyas where sea ice forms and advecting the ice southward [5]. The leading edge melts, cooling and freshening the water column. Typically, ice appears on the southern shelf in January, reaches a maximum in February or March, and is gone by mid-May [6]. In cold years, sea ice advances more than 1000 km from the Bering Strait (66°N) to the Alaskan Peninsula, while in warmer years, ice remains north of 58°N.

Historically, the southeastern Bering Sea has been characterized by high year-to-year variability in sea-ice extent in March and April [7]. This high variability was interrupted in 2001 by a five-year period of low (almost nonexistent on the southern shelf) sea-ice extent and warm ocean temperatures (2001–2005). To improve understanding of how long-term warming can impact this ecosystem, a major study (Bering Sea Project, http://www.nprb.org/bering-sea-project) was designed to explore this ecosystem from 2007 to 2010. Because of the historical record of high inter-annual variability, it was expected that at least one of the project years would also support warmer (less sea ice) conditions. Unfortunately for the Bering Sea Project, the warm period of 2001–2005 was followed by a period of extensive sea ice during spring and cold ocean temperatures over the entire eastern shelf (2007–2012) [7,8]. During the intermediate year, 2006, some ice was observed on the southern shelf and ocean temperatures were near normal.


The paper linked shows Bering avg inflows increased 50% from the 00s to 2014.. I would guess we have seen a similar year over year increase between 2017->2018 (or larger) due to the lack of sea ice. HYCOM's SSS maps clearly show the push, I would not be shocked if this yr surpassed 2-2.5Sv.
Title: Re: The 2018 melting season
Post by: Archimid on April 13, 2018, 07:55:47 PM
Animation of SSTA near the Bering Sea from March 26 to April 12 
Original images from: http://polar.ncep.noaa.gov/sst/rtg_high_res/
Title: Re: The 2018 melting season
Post by: Archimid on April 13, 2018, 08:11:59 PM
Polar SSTA's from 12 Apr 2015 to 12 Apr 2018.
Title: Re: The 2018 melting season
Post by: romett1 on April 13, 2018, 09:01:57 PM
Just looking at this real-time picture - northern winds have pushed ice away and significant body of open water can be seen. And this is just before storms and warmer weather so we should expect Chukchi Sea ice area numbers going lower soon. Image: https://weather.gc.ca/data/satellite/hrpt_dfo_ir_100.jpg
Title: Re: The 2018 melting season
Post by: Ken Feldman on April 13, 2018, 09:03:01 PM

The paper linked shows Bering avg inflows increased 50% from the 00s to 2014.. I would guess we have seen a similar year over year increase between 2017->2018 (or larger) due to the lack of sea ice. HYCOM's SSS maps clearly show the push, I would not be shocked if this yr surpassed 2-2.5Sv.

In a follow on paper (abstract available here: https://www.sciencedirect.com/science/article/pii/S0079661117302215?via%3Dihub (https://www.sciencedirect.com/science/article/pii/S0079661117302215?via%3Dihub)), the authors indicate that the increase in flow was a maximum of 1.2 Sv in 2014.  They state that the data shows a long term increase of 0.01 Sv per year.  So 2 to 2.5 Sv would seem outside of the realm of possibility.

Quote
Year-round in situ Bering Strait mooring data (1990–2015) document a long-term increase (∼0.01 Sv/yr) in the annual mean transport of Pacific waters into the Arctic. Between 2002 and 2015, all annual mean transports (except 2005 and 2012) are greater than the previously accepted climatology (∼0.8 Sv). The record-length maximum (2014: 1.2 ± 0.1 Sv) is 70% higher than the record-length minimum (2001: 0.7 ± 0.1 Sv)

The flows also seem to be dominated by pressure differences between the Pacific and the Arctic, not winds, so the absence of ice a month earlier than normal wouldn't have much influence over the flows.

Quote
By separating the flow into portions driven by (a) the local wind and (b) a far-field (Pacific-Arctic “pressure-head”) forcing, we find the increase in the Bering Strait throughflow is primarily due to a strong increase in the far-field forcing, not changes in the wind.
Title: Re: The 2018 melting season
Post by: oren on April 13, 2018, 09:41:21 PM
Some basic info about flow of water from the Bering Sea to the Arctic in this presentation:

http://psc.apl.washington.edu/HLD/Bstrait/Woodgate_AONSeattleNov2015_17thNov2015.pdf (http://psc.apl.washington.edu/HLD/Bstrait/Woodgate_AONSeattleNov2015_17thNov2015.pdf)

The linked presentation provides the results of 25 years (1990 to 2015) of monitoring flows through the Bering Strait.
Great presentation. Thanks!
Title: Re: The 2018 melting season
Post by: bbr2314 on April 13, 2018, 11:05:37 PM

The paper linked shows Bering avg inflows increased 50% from the 00s to 2014.. I would guess we have seen a similar year over year increase between 2017->2018 (or larger) due to the lack of sea ice. HYCOM's SSS maps clearly show the push, I would not be shocked if this yr surpassed 2-2.5Sv.

In a follow on paper (abstract available here: https://www.sciencedirect.com/science/article/pii/S0079661117302215?via%3Dihub (https://www.sciencedirect.com/science/article/pii/S0079661117302215?via%3Dihub)), the authors indicate that the increase in flow was a maximum of 1.2 Sv in 2014.  They state that the data shows a long term increase of 0.01 Sv per year.  So 2 to 2.5 Sv would seem outside of the realm of possibility.

Quote
Year-round in situ Bering Strait mooring data (1990–2015) document a long-term increase (∼0.01 Sv/yr) in the annual mean transport of Pacific waters into the Arctic. Between 2002 and 2015, all annual mean transports (except 2005 and 2012) are greater than the previously accepted climatology (∼0.8 Sv). The record-length maximum (2014: 1.2 ± 0.1 Sv) is 70% higher than the record-length minimum (2001: 0.7 ± 0.1 Sv)

The flows also seem to be dominated by pressure differences between the Pacific and the Arctic, not winds, so the absence of ice a month earlier than normal wouldn't have much influence over the flows.

Quote
By separating the flow into portions driven by (a) the local wind and (b) a far-field (Pacific-Arctic “pressure-head”) forcing, we find the increase in the Bering Strait throughflow is primarily due to a strong increase in the far-field forcing, not changes in the wind.

The ice wasn't absent a month earlier than normal, it barely even formed to begin with... there was literally only about 30 days of solid ice cover in the Strait this winter.

Because of how thin it was, even during February, it was vacuuming large amounts of Pac water into the Chukchi.

(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticictn_nowcast_anim365d.gif)

2014 may have been unprecedented but it was nothing compared to this year's situation, IMO, which was far worse.
Title: Re: The 2018 melting season
Post by: Pmt111500 on April 15, 2018, 01:37:42 PM
Some basic info about flow of water from the Bering Sea to the Arctic in this presentation:

http://psc.apl.washington.edu/HLD/Bstrait/Woodgate_AONSeattleNov2015_17thNov2015.pdf (http://psc.apl.washington.edu/HLD/Bstrait/Woodgate_AONSeattleNov2015_17thNov2015.pdf)

The linked presentation provides the results of 25 years (1990 to 2015) of monitoring flows through the Bering Strait.
Great presentation. Thanks!
Adding my thanks. Great presentation.
Title: Re: The 2018 melting season
Post by: uniquorn on April 15, 2018, 03:46:59 PM
Chukchi yesterday and ascat animation jan-apr14.

worldview aqua modis
ascat:
ImageJ brightness/contrast 53-255,CLAHE 63-255-2.2
gimp duplicate final frame,scale 200% unsharp mask 5,0.5,0
(A-team tips)
edit:unsharp mask needs more work, went back to sharpen 50
Title: Re: The 2018 melting season
Post by: uniquorn on April 15, 2018, 07:33:17 PM
Floes in the 'Kara tongue' NE of Svalbard 'drifting to their doom'. Mostly first year ice held together with younger refreeze.

Worldview aqua/modis and VIIRS temperature brightness band 15, night
Title: Re: The 2018 melting season
Post by: uniquorn on April 15, 2018, 10:03:19 PM
I read somewhere up thread that sea ice temperature may be as useful as air temperature for estimating increase in ice thickness but I found it difficult to visualise a daily animation  from DMI due to weather interference. A 10 day average makes it easier. Unfortunately data is missing from oct20 to nov23rd so I've repeated the two nearest frames.
Quote
At DMI, the temperature of the surface is not measured directly. Instead, observations are used from three infrared channels on the “Advanced Very High Resolution Radiometer” (AVHRR), which is on board the MetOp-A satellite. The instrument is unable to see through clouds, however. A statistical method is therefore used to provide the missing data. The edge of the ice is shown as a black contour line. It is defined by a sea ice concentration of 15%, i.e. 15% of the surface is covered by ice.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 15, 2018, 10:13:20 PM
From the acclaimed makers of

(https://whbpac.org/wp-content/uploads/2017/07/Bye-Bye-Birdie-web.jpg)

Comes the 2018 edition, out this May:

"Bye Bye Beaufort"

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Focean.dmi.dk%2Fanim%2Fplots%2Fice.arc.121.png&hash=82d515f5b606e7dc5d7121e3032bd7f3)
Title: Re: The 2018 melting season
Post by: uniquorn on April 15, 2018, 10:22:18 PM
It does look a bit challenged but I think other years have been worse.
worldview brightness temperature viirs band 15, night apr14
Title: Re: The 2018 melting season
Post by: numerobis on April 16, 2018, 04:33:10 AM
ECMWF shows a strong high pressure parked over eastern Hudson Bay for the next week, with another high parked over the western Canadian Arctic for some of those days.

It's going to be a bright, bright, bright, sunshiny week.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 16, 2018, 04:42:55 AM
ECMWF shows a strong high pressure parked over eastern Hudson Bay for the next week, with another high parked over the western Canadian Arctic for some of those days.

It's going to be a bright, bright, bright, sunshiny week.
The ECMWF has consistently been adjusting colder across Canada. It ejects the airmass out too quick each and every run. I am also wondering if it has climo biases that are now making it less accurate vs normal bc the on-the-ground situation is not climo.

It has also been to cold over Bering/Chukchi. I suspect this discrepancy will worsen as we move forward and Bering/Chukchi will bear... formidable heat... very soon.

E.G.

Verification:

(https://www.tropicaltidbits.com/analysis/models/ecmwf/2018041512/ecmwf_T850_namer_1.png)

D7 forecast:

(https://www.tropicaltidbits.com/analysis/models/ecmwf/2018040812/ecmwf_T850_namer_8.png)

(https://media.giphy.com/media/2Yj0qXlK28ujZxbUny/giphy.gif)

Also: just discovered this excellent tool showing how terrible the GFS is / has been this year.

http://www.karstenhaustein.com/reanalysis/gfs0p5/ANOM2m_arctic/verification/ANOM2m_bias_past07_arctic.png

The reds are where it has been to warm, the blues, where it has been too cold.

The GFS has a very major problem modeling the Canadian Shield, evidently.

http://www.karstenhaustein.com/reanalysis/gfs0p5/ANOM2m_ntham/verification/ANOM2m_bias_past07_ntham.html
Title: Re: The 2018 melting season
Post by: Jim Hunt on April 16, 2018, 10:42:14 AM
It does look a bit challenged but I think other years have been worse.

They most certainly have. See mid April 2016 for example:

http://GreatWhiteCon.info/2016/04/the-beaufort-gyre-goes-into-overdrive/
Title: Re: The 2018 melting season
Post by: be cause on April 16, 2018, 11:07:48 AM
Hi Jim .. your Beaufort AMSR2 area graph above shows no recent drop , while the current graph at GWC shows a drop of @ 50,000 km in the last week .. something needs corrected .. cheers b.c.

ps .. seems it's  me that needs correcting .. graph I was looking at on gwc was 2016 ..
Title: Re: The 2018 melting season
Post by: Neven on April 16, 2018, 11:17:39 AM
BC, if you mean this map, it's for last year:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fgreatwhitecon.info%2Fwp-content%2Fuploads%2F2015%2F05%2FUH-Beaufort-Area-2017-05-15.png&hash=0a6a053ac7a575e57c94e13639be19ce)
Title: Re: The 2018 melting season
Post by: colchonero on April 16, 2018, 11:19:34 AM
One question about these anomalies and this sentence "The reds are where it has been too warm, the blues, where it has been too cold."

Does the red mean it was forecasted too warm(and it was actually colder for that difference), or does it mean it was that much warmer than the cold forecast over that part of the globe?
Title: Re: The 2018 melting season
Post by: numerobis on April 16, 2018, 01:32:43 PM
bbr2314: sunshine matters more than temperature during the day (and there’s more day than night now). At -15, in the beating sun, snow melts.

Over the past few days that it’s been -15 and colder in Iqaluit, the snow has melted off the tundra in many places. It’s also been melting off roads to form streams and puddles.

And we’re forecasting most of the Canadian Arctic to be sunny. Good conditions for melt ponding, perhaps? Hopefully not.
Title: Re: The 2018 melting season
Post by: Jim Hunt on April 16, 2018, 04:15:26 PM
ps .. seems it's  me that needs correcting .. graph I was looking at on gwc was 2016 ..

2017 I think? That graph is manually updated, and it hasn't done anything of note this year. Yet!

However I just updated it to avoid any possible future confusion.
Title: Re: The 2018 melting season
Post by: FishOutofWater on April 16, 2018, 05:22:07 PM
The GFS has been moving the short waves faster than reality so the 168 hour forecast looks horrid. It's not quite so bad if you correct for the excess speed. It helps to compare the ECMWF runs with the GFS runs to see how the forecasts are likely to be off.

This year the blocking in the Bering and Chukchi sea region has been persistent, causing the GFS no end of trouble. All models have trouble with blocks, especially the GFS. That's why the GFS has been so bad forecasting the Arctic weather, in my opinion.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 16, 2018, 05:30:49 PM
The GFS has been moving the short waves faster than reality so the 168 hour forecast looks horrid. It's not quite so bad if you correct for the excess speed. It helps to compare the ECMWF runs with the GFS runs to see how the forecasts are likely to be off.

This year the blocking in the Bering and Chukchi sea region has been persistent, causing the GFS no end of trouble. All models have trouble with blocks, especially the GFS. That's why the GFS has been so bad forecasting the Arctic weather, in my opinion.
The GFS has been complete garbage. You cannot blame weather for a model's terrible output -- it is the model. The Canadian has been far superior.
Title: Re: The 2018 melting season
Post by: litesong on April 16, 2018, 06:09:25 PM
I too sense some denial with Daniel B. but this is off topic. So lets keep on topic.
Read more of AGW denier daniel, & you will know he is an AGW denier. If AGW deniers post in error, no post to oppose their error is off-topic.
Ok, he is a denier so what? It's just his current opinion. It might be wrong or ignorant from your perspective.....
This forum is calm with a lack of AGW deniers. Hope 10 or more AGW deniers don't show up, with less...."delicacy" than daniel. There is much AGW denier energy, self-righteousness & money floating lots of AGW denier  websites. Not to oppose AGW deniers is a mistake that AGW proponents have to correct. AGW scientists are learning this lesson.... belatedly.   
Title: Re: The 2018 melting season
Post by: FishOutofWater on April 16, 2018, 06:19:09 PM
"Complete garbage" is something you throw in the trash. I'm interested in the hows and whys of model performance so I can scrape any useful information from them and so that the programmers can improve them. The CFSv2 seems to have some luck in forecasting large scale subsidence and uplift anomalies associated with SST anomalies and general atmospheric dynamics. However, its forecasts of sea ice extent are pretty close to garbage.  I'm not satisfied with any of the means that are being used to forecast the melt season. There is no model that does a good job of coupling the physics of the atmosphere, the ice and the ocean to predict sea ice extent, area and volume.

Perhaps the Canadian model does a good job of handling the physics of snow and ice. The American models certainly don't.

The closest year to 2018, in terms of the atmospheric dynamics of NH early spring and late winter, is 2006. Both years had major stratospheric warmings in mid to late February and cold weather that followed in eastern north America and western Europe.  Summer 2006 was a relatively good one for preserving Arctic sea ice. Will the Arctic weather this summer be like summer 2006? I suspect not, because of differences in ocean dynamics and ocean heat distribution, but 2006 may be the best analog year to 2018. Tropical Tidbits looks at analog years for helping with seasonal hurricane forecasts. Last year,  Levi Cohen's Atlantic hurricane forecast was for less than normal hurricane activity so, be careful, but perhaps there's a 12 year cycle given that 2005 was one of the most active hurricane seasons ever and so was 2017. This is relevant to the Arctic because there's a connection between the ocean heat in the tropical Atlantic and the weather in the Arctic.
Title: Re: The 2018 melting season
Post by: colchonero on April 16, 2018, 08:05:15 PM
This forum is calm with a lack of AGW deniers. Hope 10 or more AGW deniers don't show up, with less...."delicacy" than daniel. There is much AGW denier energy, self-righteousness & money floating lots of AGW denier  websites. Not to oppose AGW deniers is a mistake that AGW proponents have to correct. AGW scientists are learning this lesson.... belatedly.

Okaaay, I guess ??? ???. That's your view on that issue. I think, I can agree partially, partially not (I would agree that GW is totally real, I wouldn't agree on opposing people that doesn't think the same.  I mean opposing is completely fine, but history learned me it doesn't always stick to just opposing, it always begins like that, but sometimes it evolves into telling people what they must accept and mocking them if they don't. Like so many other things in the past, some very good, some not at all.  But we can argue about it some other time via PM, but that has nothing, but really nothing to do with my commenting on how you express yourself to Daniel and how ridiculous is to mention someone in the way mentioned in that comment and I've tried to explain why. My point had nothing to do with how many deniers are here or is that good or bad thing. It wasn't even about deniers, that just happened to be a coincidence because we are on climate forum. It had to do how you should address people in the way that would actually make sense. Apples and oranges. This is my second and last off-topic comment on this.
Title: Re: The 2018 melting season
Post by: Gray-Wolf on April 17, 2018, 12:47:50 PM
I'm still watching to see if we have a low solar link to HP blocking early on in the melt season?

We already know that NW Europe sees more northern blocking over winter through low solar ( MetO released a paper on it last low solar?) so does this drift north at winters end keeping clear skies over Barentsz/Kara for the spring.

If 2006 is the close analog that might mean the UK getting a summer this year! It would also hint at a return of 2007 next year......

Any of the 'record' years over last low solar would be disastrous for the type of ice we have in the basin now. It is not like the ice back in 2006 as the thickness or FDD plots show us. Its fragmented nature will also add into its ability to go far faster than in the past with the increased mobility it brings ( with 'hostile waters inside the basin by Aug) and 'side melt' becoming important in the smaller ( less than 100m?) floes.

If there is anything in low solar allowing HP dominance in the basin over early melt season then we will have a few years yet where the 'perfect melt storm' might put in an appearance?
Title: Re: The 2018 melting season
Post by: uniquorn on April 17, 2018, 04:54:29 PM
Fram Strait and Svalbard Apr13-17.
Ice from the 'Kara tongue' (top left) doesn't last long as it meets the atlantic front. Warmer southerlies were accompanied by cloud cover, pushing back the ice front nearer Greenland with another small lift off from the fast ice on the Nth Greenland coast.
Not much wind resistance anywhere, it seems.

Worldview terra/modis
Title: Re: The 2018 melting season
Post by: bbr2314 on April 17, 2018, 08:14:50 PM
I'm still watching to see if we have a low solar link to HP blocking early on in the melt season?

We already know that NW Europe sees more northern blocking over winter through low solar ( MetO released a paper on it last low solar?) so does this drift north at winters end keeping clear skies over Barentsz/Kara for the spring.

If 2006 is the close analog that might mean the UK getting a summer this year! It would also hint at a return of 2007 next year......

Any of the 'record' years over last low solar would be disastrous for the type of ice we have in the basin now. It is not like the ice back in 2006 as the thickness or FDD plots show us. Its fragmented nature will also add into its ability to go far faster than in the past with the increased mobility it brings ( with 'hostile waters inside the basin by Aug) and 'side melt' becoming important in the smaller ( less than 100m?) floes.

If there is anything in low solar allowing HP dominance in the basin over early melt season then we will have a few years yet where the 'perfect melt storm' might put in an appearance?
I like 2009 as an analog. But that is just me. That was a year without a summer until August for most of the US.

It also saw an enormous amount of warmth/fresh melt do damage to AMOC. I suspect this will begin occurring this year as sea ice continues dwindling, much earlier than normal, while snow melt is happening much later than normal. This portends a frigid summer across the northern tier and perhaps the UK/etc as well.

We still have another few days of gains on this graph btw (IMO)... simply incredible...

(https://ccin.ca/home/sites/default/files/snow/snow_tracker/na_swe.png)
Title: Re: The 2018 melting season
Post by: dosibl on April 17, 2018, 08:59:10 PM
bbr2314 is there a reason you are going with the North America version of that graph? The melting trend is much more noticeable on the Northern Hemisphere version.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 17, 2018, 09:09:31 PM
bbr2314 is there a reason you are going with the North America version of that graph? The melting trend is much more noticeable on the Northern Hemisphere version.
NHEM may be melting but North America is not. Eurasia is also still wayyyy above normal.

I think something has happened in the high Arctic / oceanic heat, where previously we would have had a more uniform melt distribution. Now, I think the forcing from all the oceanic heat has sufficed to trap more of the airmasses that originate in Greenland in North America, instead of allowing them to circulate more fully down to Europe/Eurasia (obviously there is still movement, but this year has become increasingly stagnant).

The EURO continues adjusting colder and colder, the bias is ridiculous, but even with the bias, it looks like another PV is going to plunge into North America by the end of the month... we may see no substantial SWE losses through the entirety of April!

(https://www.tropicaltidbits.com/analysis/models/ecmwf/2018041712/ecmwf_T850_namer_11.png)

Also of note: extent is also now beginning to gape relative to normal. I suspect the Rutgers # for April will be the highest ever, at least in North America.

What does this mean for the high Arctic? I think it means that the seas peripheral to the Pacific/Eurasia are going to bear the brunt of the atmospheric heat this summer, while the Atlantic side is going to be most vulnerable to SSTs, but may actually enjoy relatively cold temps. This could result in a September state featuring an "ice bridge" between the N Siberian Islands and Svalbard/Greenland, while Beaufort/Chukchi and almost all of the western CAB is ice-free. I think CAA and Hudson Bay will also be relatively "safe" vs. normal. But this may not be sufficient to prevent a new record low.

Title: Re: The 2018 melting season
Post by: dosibl on April 17, 2018, 09:54:10 PM
Thanks for expanding on that a bit, always useful to see what others are looking at. SWE is way up but extent is still pretty standard, not sure what to make of that (other than the fact I've been enjoying the north american ski season the past few years).
Title: Re: The 2018 melting season
Post by: Thomas Barlow on April 17, 2018, 11:07:59 PM
With some similar levels in the mid 2000s at this time of year, it is interesting to note that 4 years in a row now are all at the lowest levels for this date (this year, the date - Apr. 16 - being the lowest on record).
http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Title: Re: The 2018 melting season
Post by: be cause on April 18, 2018, 02:03:09 AM
bbr2314 .. your N.American snow graph has not updated in 3 weeks .. can you describe what you can see that we can't ?  b.c.
Title: Re: The 2018 melting season
Post by: Csnavywx on April 18, 2018, 02:04:17 AM
The full SSW split in Feb. is responsible for this pattern. Downstream effects from a SSW of that magnitude can easily last over two months.
Title: Re: The 2018 melting season
Post by: oren on April 18, 2018, 02:16:51 AM
bbr2314 .. your N.American snow graph has not updated in 3 weeks .. can you describe what you can see that we can't ?  b.c.
Though I'm kinda tired of this snow thing - I think this is the proper link for the direct NA SWE chart, try it, and make sure to hit refresh.
https://www.ccin.ca/home/sites/default/files/snow/snow_tracker/na_swe.png (https://www.ccin.ca/home/sites/default/files/snow/snow_tracker/na_swe.png)
Title: Re: The 2018 melting season
Post by: bbr2314 on April 18, 2018, 04:00:39 AM
bbr2314 .. your N.American snow graph has not updated in 3 weeks .. can you describe what you can see that we can't ?  b.c.
Though I'm kinda tired of this snow thing - I think this is the proper link for the direct NA SWE chart, try it, and make sure to hit refresh.
https://www.ccin.ca/home/sites/default/files/snow/snow_tracker/na_swe.png (https://www.ccin.ca/home/sites/default/files/snow/snow_tracker/na_swe.png)
Yep, just hit refresh, sorry for posting, I try to keep it in the other thread unless I can relate my points to sea ice (also it is absolutely crazy how it keeps going up).
Title: Re: The 2018 melting season
Post by: JayW on April 18, 2018, 12:58:26 PM
100 hour loop of Chukchi and some Beaufort.  April 13-17.

http://feeder.gina.alaska.edu/npp-gina-alaska-truecolor-images?search%5Bfeeds%5D%5B5%5D=1&search%5Bsensors%5D%5B3%5D=1
Title: Re: The 2018 melting season
Post by: FishOutofWater on April 18, 2018, 05:43:39 PM
The effects of the stratospheric warming / polar vortex split were greater than I expected. I did not expect such a strong expansion and increase of the angular momentum of the NH jet stream. It gave California much needed rains and shifted the distribution of heat in the Pacific ocean. Both the north Atlantic and north Pacific oceans are are significantly warmer than normal while the central and northeastern U.S. are ridiculously cold. The thin snow in Asia melted quickly so that positive anomaly has faded, but the north American anomaly is amazingly high.

Meanwhile the Bering sea has almost no ice left at all.

Expect weird jet stream patterns to continue.
Title: Re: The 2018 melting season
Post by: Dharma Rupa on April 18, 2018, 09:07:45 PM
The effects of the stratospheric warming / polar vortex split were greater than I expected. I did not expect such a strong expansion and increase of the angular momentum of the NH jet stream. It gave California much needed rains and shifted the distribution of heat in the Pacific ocean. Both the north Atlantic and north Pacific oceans are are significantly warmer than normal while the central and northeastern U.S. are ridiculously cold. The thin snow in Asia melted quickly so that positive anomaly has faded, but the north American anomaly is amazingly high.

Meanwhile the Bering sea has almost no ice left at all.

Expect weird jet stream patterns to continue.

Living in Boston, I am well aware of the cold energy running smack into the Gulf Stream just east of me.
Title: Re: The 2018 melting season
Post by: meddoc on April 19, 2018, 08:14:29 AM
This looks like rather snow accumulation than Ice to me, in the Beaufort. Max. 60- 80 cm thick, no Resistance at all by Breakthrough.

https://www.youtube.com/watch?v=Yf5ggIkym9I
Title: Re: The 2018 melting season
Post by: Jim Hunt on April 19, 2018, 10:07:13 AM
This looks like rather snow accumulation than Ice to me, in the Beaufort.

Bear in mind that spot was carefully chosen and not typical of the sea ice situation in the Beaufort Sea at the moment. See the ridges in the background for example.
Title: Re: The 2018 melting season
Post by: uniquorn on April 19, 2018, 01:08:45 PM
Beaufort Apr16-18 terra/modis with viirs for further detail.
Title: Re: The 2018 melting season
Post by: slow wing on April 19, 2018, 01:16:20 PM
A sea ice region to watch at the moment is North of Svalbard, with:

I looked on Worldview at previous years and this is already an unusual amount of this type of flaking for the date.

With the wind potentially opening up the leads wider, it will be interesting to see if there is even more flaking to follow, and also how much the flaking might compromise the survivability of the ice in this region over the course of the melt season.

Or, instead, is it early enough in the year that these leads might still freeze over?
Title: Re: The 2018 melting season
Post by: bbr2314 on April 19, 2018, 07:40:33 PM
(https://www.tropicaltidbits.com/analysis/models/gfs/2018041912/gfs_T2m_nhem_36.png)

Yikes

Maybe 2018 will begin putting distance between itself and 2016?

As we delve deeper into May I anticipate we see the same thing that has happened to Bering occur in both Chukchi and Beaufort as the importation of heat has been incessant for the past year. This is also likely to result in a substantial volume push toward the Atlantic front. Maybe we see ice begin to surge past Svalbard even WITH all the melt?

This would setup an extremely low minimum, likely record setting.
Title: Re: The 2018 melting season
Post by: jdallen on April 19, 2018, 09:58:24 PM
A sea ice region to watch at the moment is North of Svalbard, with:
<snip>

Or, instead, is it early enough in the year that these leads might still freeze over?
It really won't make much difference even if they do.  It won't get more than a few 10's of CM thick and structurally will be very weak.  In a few weeks, the least provocation will crush it to ice cubes, and temperatures generally are close to the -10C limit which anecdotally is considered the threshold above which ice really can't form.
Title: Re: The 2018 melting season
Post by: jdallen on April 19, 2018, 10:03:05 PM
Bering sea ice?  What Bering sea ice?

Dark humor aside, what there is, which isn't much, appears to be attempting to escape to the Chukchi.  Aside from a little land fast ice on the Siberian shore, what's left appears to be relict blocks and slash.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 20, 2018, 07:04:03 AM
<snip, too long, not on-topic enough; N.>
Title: Re: The 2018 melting season
Post by: binntho on April 20, 2018, 08:01:27 AM
bbr2314, you seem to have landed in the wrong forum again!
Title: Re: The 2018 melting season
Post by: bbr2314 on April 20, 2018, 08:09:18 AM
bbr2314, you seem to have landed in the wrong forum again!
If Neven wants to move it he can move it I think I have given up on deciding where to post things that relate to both SWE and sea ice, the level of OCD here is understandable but nonsensical
Title: Re: The 2018 melting season
Post by: binntho on April 20, 2018, 08:09:45 AM
With fairly clear skies, animations are once again the thing. The following animation shows the open ocean north of Svalbard (north is towards the top left corner). There seem to be two separate areas of ice, the one to the north that moves more or less to the south, and the one to the east that seems to move in a different manner.

The wind direction can be seen in many frames from the beautiful cloud striations, mostly from north but a few days with southerly winds and clouded weather. I've marked one particular floe with a red dot, it moves south by some 120 km over 19 days, and will presumably disappear within the next 24 hours.

The ice edge is some 100 km north of Svalbard in the last frame, slightly further than in the first frame. The ice that floats into this 100km wide and 200km long killing zone can be seen to melt to shreds over very short distances.

Title: Re: The 2018 melting season
Post by: binntho on April 20, 2018, 08:13:17 AM
bbr2314, you seem to have landed in the wrong forum again!
If Neven wants to move it he can move it I think I have given up on deciding where to post things that relate to both SWE and sea ice, the level of OCD here is understandable but nonsensical
I think you misunderstand the division of labor here, it's not Neven's job to place postings in the right forums. I guess you can use the following as a rule of thumb: Speculation regarding snow and it's presumed and possible effects on the current melting season belong in the Land snow cover effect on sea ice (https://forum.arctic-sea-ice.net/index.php/topic,292.0.html) forum.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 20, 2018, 08:16:28 AM
bbr2314, you seem to have landed in the wrong forum again!
If Neven wants to move it he can move it I think I have given up on deciding where to post things that relate to both SWE and sea ice, the level of OCD here is understandable but nonsensical
I think you misunderstand the division of labor here, it's not Neven's job to place postings in the right forums. I guess you can use the following as a rule of thumb: Speculation regarding snow and it's presumed and possible effects on the current melting season belong in the Land snow cover effect on sea ice (https://forum.arctic-sea-ice.net/index.php/topic,292.0.html) forum.

Neven said posts in the melting thread were occasionally OK. It isn't your job to police postings, you are a rando on the internet, not a mod.
Title: Re: The 2018 melting season
Post by: Neven on April 20, 2018, 08:46:04 AM
Neven says: Don't post those long screeds about what Snow Water Equivalent portends for the future. Just post a graph and say: SWE in North America still extremely high, much higher than in xxxx and yyyy. This thread is for what's going on right now, as compared to past years.
Title: Re: The 2018 melting season
Post by: DavidR on April 20, 2018, 10:34:29 AM
bbr2314, you seem to have landed in the wrong forum again!
If Neven wants to move it he can move it I think I have given up on deciding where to post things that relate to both SWE and sea ice, the level of OCD here is understandable but nonsensical
As I  understand it the 'season' as used here refers to the weather not everything that  happens in the northern hemisphere between March and September. The point of having separate threads is to separate discussions so they are easy to follow. There is always some overlap but putting everything under the 'season' is equivalent  to  putting  everything on your computer desktop and never organizing it. It doesn't take a lot of effort to find more relevant threads and it saves everybody a lot of wasted time looking at  topics they are disinterested in.
Title: Re: The 2018 melting season
Post by: pauldry600 on April 20, 2018, 01:43:12 PM
Hvnt been on here in ages

Hope all's well

Looking at melting and I was sure there was more in previous years

Maybe it's coz we are starting at such a low base it's slowed down after below normal Max.

For some reason though I think there will be not much melt at all this year and we may get back to the median.

Reason is.... I don't know

Does anybody else think this or am I alone

I certainly think that the trend will continue down but I think the ssw may have shook things up a little for 2018 anyhow
Title: Re: The 2018 melting season
Post by: Neven on April 20, 2018, 01:54:51 PM
I think the weather we've had in April so far, mainly characterized by high pressure over the Central Arctic, has been beneficial to the ice pack overall. But if this pattern continues into May, it will be very bad for the ice.

The thing is we haven't seen any serious melt pond formation during May and June since 2012. I don't know if there's some kind of feedback responsible for that (something that causes cloudy weather patterns during May and June) , but the longer it takes, the stronger the suggestion that there might be.
Title: Re: The 2018 melting season
Post by: numerobis on April 20, 2018, 04:06:11 PM
Why is high pressure in April beneficial? Keeps transport down?
Title: Re: The 2018 melting season
Post by: RoxTheGeologist on April 20, 2018, 05:48:27 PM
Why is high pressure in April beneficial? Keeps transport down?

Central Arctic ice is still thickening, hence why volume peaks later than extent. In April the insolation from the low angle sunlight isn't high enough to compensate for radiation into space with no clouds. Basically, In may, the sun is warmer and clear skys promote ice melt rather than growth.
Title: Re: The 2018 melting season
Post by: FishOutofWater on April 20, 2018, 09:43:16 PM
The weather certainly has been warmer than normal on the Alaskan side of the Arctic ocean. There have been far too many penetrations of warm air over the past month from the Pacific for it to be a good month on the Pacific side of the Arctic.

The Atlantic side has had much more favorable conditions for sea ice.

The surface pressure anomaly pattern for the past 30 days shows a strong dipole anomaly through the Bering strait pushing Pacific water and warm southerly winds into the Arctic. This was not a nice pattern of high pressure over the pole.
Title: Re: The 2018 melting season
Post by: Dryland on April 20, 2018, 10:40:11 PM
The thing is we haven't seen any serious melt pond formation during May and June since 2012. I don't know if there's some kind of feedback responsible for that (something that causes cloudy weather patterns during May and June) , but the longer it takes, the stronger the suggestion that there might be.

My (speculative) takeaway from last year's melt pond season, and the discussion around it, was that in many areas the ice was just too fractured to sustain melt ponds; too many paths for meltwater to drain off instead of accumulating. If true, this would seem to be a negative feedback (drained ice having a higher albedo than a pond). But in the larger context, the transition from solid to fractured ice can't be a good thing.
Title: Re: The 2018 melting season
Post by: litesong on April 20, 2018, 11:31:30 PM
2018 Arctic sea ice has already dropped ~ 1 million square kilometers from its maximum. Average 1980 decade Arctic sea ice didn't reach 12.89 million square kilometers till May 23, with the sun approaching highest elevation in the sky. 
Title: Re: The 2018 melting season
Post by: Bob Wallace on April 21, 2018, 07:00:30 AM
Looking at the ARC Ice Thickness gif I see almost no yellow/red/black. 

Am I misremembering this as unusual?  Seems like this time of year there's a bunch of thick stuff.  This year it all looks meltable.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 21, 2018, 07:05:00 AM
Looking at the ARC Ice Thickness gif I see almost no yellow/red/black. 

Am I misremembering this as unusual?  Seems like this time of year there's a bunch of thick stuff.  This year it all looks meltable.
Nope, we are really screwed this year across the entire Pacific flank, the impending intrusion of warm salty Pac water is going to slice through the snow-covered bits of slush that constitute the Chukchi, Beaufort, and most of the CAB like butter. The Bering is now almost entirely ice-free.

(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticsss_nowcast_anim30d.gif)

(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticsst_nowcast_anim30d.gif)

If tonight's 00z GFS is anywhere close to reality (and it has been too COLD over the warmest areas it shows recently), we are going to put substantial distance between 2018 and 2016 by 5/15 in a direction that is extremely bad for the minimum.
Title: Re: The 2018 melting season
Post by: gerontocrat on April 21, 2018, 11:15:48 AM
Perhaps this belongs in "stupid questions"?

It is Spring in the Northern Hemisphere.
We are into the 4 months of maximum insolation.
The sun is higher in the sky.
Day time temperatures (especially on sunny days) are far higher than both night-time and average temperatures.

So for heating of the open waters of the Arctic, melting of sea-ice (and of snow) is it more useful to look at maximum temperatures than average temperatures ?

The large contrast between the maximum and average temperatures is illustrated in the two images below.

Title: Re: The 2018 melting season
Post by: Shared Humanity on April 21, 2018, 05:49:34 PM
My 1st thought was maximum temp but wouldn't average better capture the amount of heat available to melt snow?
Title: Re: The 2018 melting season
Post by: gerontocrat on April 21, 2018, 05:55:49 PM
My 1st thought was maximum temp but wouldn't average better capture the amount of heat available to melt snow?

My thinking is (all because I remember a few days and nights in the Jordanian deserts and reading about a dry valley in North Greenland that can get well above 30 degrees in day time in June but freezes at night ) :-

Imagine we are at 60+ North at any time between late April and late August

It is a sunny day, insolation way up and snow / ice melting like crazy.
At night the temperature drops like a stone (even if the sun is just visible above the horizon).

The average temperature therefore could be below zero, but melt has occurred - big time.

So really need both max temperature plus cloud cover.
cci-renalyzer does a 10 day accumulated precipitation map -low precipitation a proxy for less cloud cover?
Title: Re: The 2018 melting season
Post by: Tor Bejnar on April 21, 2018, 06:47:38 PM
Re: max vs. ave:  I concur, gerontocrat.  A little melting will change snow's albedo.  Of course, snow surface changes happen with temps continuously below freezing, but with sublimation (due to a combination of sun power, wind and humidity).
Title: Re: The 2018 melting season
Post by: oren on April 21, 2018, 07:19:00 PM
From what I recall looking at buoy movies, when it's warm and sunny and the snow melts, it mostly still remains as melt ponds, which quickly freeze over when it becomes cold again. Later when it becomes warm, the same melt pond forms, rather than expand and deepen. So although it does change albedo, I still think that mostly the average temperature is what matters.  The same surely applies to ocean surface, ice melt too, the only caveat being direct snow sublimation where max temp and insolation are what counts.
Title: Re: The 2018 melting season
Post by: oren on April 21, 2018, 07:22:06 PM
Cross-posting from the data thread:
The Chukchi Sea region is still cold enough to resurface itself with ice when big open ocean areas form.  This will stop soon, so I expect to see major drops in ice extent soon.
All the areas that were exposed recently in the Chukchi are now covered by very thin ice (shown in SMOS below) which could go very quickly once heat arrives. The rest of the Chukchi is hopefully more resilient.
The Barents also seems to be a nest of troubles waiting to happen, as all ice there is thin.
Title: Re: The 2018 melting season
Post by: numerobis on April 21, 2018, 09:31:08 PM
Insolation makes the biggest difference to surface conditions around here. Cloudy and -2 => no melting. Sunny and -15 => puddles everywhere in town. In shaded spots we have snow that persists well into August, despite months of above-freezing temperatures with some rain.

Out on the sea ice, we don't see puddles yet; it's snow-covered everywhere (except in the rough ice, near shore, where the tide can seep through cracks). The snow is also generally much cleaner than in town so it won't melt quite as easily (again, except in the rough ice, which contains a lot of sand).

I'm curious about the mechanics of snow melt on sea ice prior to melt pond formation. Does the melted fresh water seep down to the sea ice and deposit its heat there, helping it melt faster?

(Edit: this all applies to surface conditions. Cold temperatures can suck heat out through the ice and allow freezing on the bottom, whereas warm temperatures would slow that heat flow and allow the bottom to start to warm up.)
Title: Re: The 2018 melting season
Post by: bbr2314 on April 21, 2018, 10:01:57 PM
When the CMC shows this amount of heat it is time to get very concerned:

(https://www.tropicaltidbits.com/analysis/models/gem/2018042112/gem_T2m_namer_36.png)
Title: Re: The 2018 melting season
Post by: Dharma Rupa on April 22, 2018, 12:05:09 AM
My 1st thought was maximum temp but wouldn't average better capture the amount of heat available to melt snow?

You can start with the Integral, or the Integral divided by whatever time unit you want to use...then add the complications caused by variable albedo and insolation.  I'd assume that average is going to be closer to total area under the graph of temperature than max.
Title: Re: The 2018 melting season
Post by: gerontocrat on April 22, 2018, 12:57:22 AM
It is always gratifying when a total amateur like me can ask a question and get so many responses.
I will be looking at the Chukchi on the Alaska shore - the max temps over the next 5 days look high and precipitation looks low. Will the ice melt?

If it does, I will, of course, cite it as 100% proof of my speculation. 

Title: Re: The 2018 melting season
Post by: bbr2314 on April 22, 2018, 03:02:48 AM
It would be nice if someone took a look and verified because it looks like another funky thing is happening. It appears that Baffin ice is now being entrained into Hudson Strait, by a wayward push of the Irminger Current (?) which appears to be flexing extremely strong this year. The ice being entrained is roughly north of the line drawn below (closest to the coast, it seems to be funneling in between the islands).

https://worldview.earthdata.nasa.gov/?p=geographic&l=MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2018-04-21&z=3&v=-72.68146330473414,56.23692924539198,-50.18146330473414,67.31114799539198

Does this happen often? I can't seem to recall seeing this before.
Title: Re: The 2018 melting season
Post by: Neven on April 22, 2018, 02:54:44 PM
I thought there was a shift coming, but high pressure remains dominant over the CAB:
Title: Re: The 2018 melting season
Post by: Greenbelt on April 23, 2018, 01:22:26 AM
Looks like the GFS favors high pressure too, well out into the extended.
(https://www.tropicaltidbits.com/analysis/models/gfs/2018042218/gfs_z500_mslp_nhem_38.png)
Title: Re: The 2018 melting season
Post by: S.Pansa on April 23, 2018, 09:27:28 AM
Currently the newly opening areas in the Bering Strait seem to refreeze (https://go.nasa.gov/2JhGFoY). But this ice might have a very short live span.
Latest model runs predict temps will be briefly above zero form Wednesday on. The "heat wave" is - for now - forecasted to culminate next Sunday with southerly winds. 
Even though it is still far out, GFS & ECMWF are in good agreement. For once, ECMWF seems to be more bullish while both models continue to show huge differences in snow height.

Could be interesting. Open water south to a line from Barrow to Pevec in early May? At least snow cover should get a big hit. We will see ...


Title: Re: The 2018 melting season
Post by: oren on April 23, 2018, 11:23:09 AM
Currently the newly opening areas in the Bering Strait seem to refreeze. But this ice might have a very short live span.
The newly formed ice in the strait area and on the Alaskan side of the Chukchi is even more vulnerable than its thickness indicates, as it probably lacks any snow cover.
Title: Re: The 2018 melting season
Post by: Daniel B. on April 23, 2018, 05:42:39 PM
2018 Arctic sea ice has already dropped ~ 1 million square kilometers from its maximum. Average 1980 decade Arctic sea ice didn't reach 12.89 million square kilometers till May 23, with the sun approaching highest elevation in the sky.

The ice drop over the past 30 days is fairly average.  Those years that have had higher melt through the first month have not shown a tendency towards a new minimum; 1990 being the lone exception.  Contrarily those years in which the melting season starting slowly, did not show any propensity towards higher minima.  There was a slightly greater tendency towards higher first month melt in those years with higher maxima, but even that was rather nebulous.  2012 had a relatively high maximum, and a slow first month's melt, but took a nose dive later in the summer.  So far, 2018 Arctic sea ice melt has shown nothing memorable.
Title: Re: The 2018 melting season
Post by: FishOutofWater on April 23, 2018, 05:56:16 PM
What's memorable about this year is the record shattering low amount of ice in the Bering sea through the whole freezing season. There's nothing special about the first month of the melt season.
Title: Re: The 2018 melting season
Post by: Lord M Vader on April 23, 2018, 06:15:57 PM
FOW, oh yes, it IS memorable and spectacular with the exceptionally low sea ice concentration in Bering Sea. As the waters there are open now, the ocean is now able to store all heat from the sun. And I assure you that the sun is rather strong this time at year. In fact, the sun is now above the horizon for about 15 hours per day in this area.

Instead of being reflected, the sunlight has already started to warm the ocean there. According to eart.nullschool.net the SSTs in this area is now -0,8o to -1,4o. I think we can imagine that it should be a lot harder for the sea ice to form in this area later this year, or perhaps even in January if we are going to see a repeat of stormy weather there.
Title: Re: The 2018 melting season
Post by: Trebuchet on April 23, 2018, 07:33:53 PM
The isolation is already keeping the southern Chukchi from refreezing (Kotzebue sound) looking at the past few days on Worldview.
Title: Re: The 2018 melting season
Post by: oren on April 23, 2018, 07:45:35 PM
It's not just insolation, but also the effect of the warm Alaska coastal current.
Title: Re: The 2018 melting season
Post by: Sarat on April 23, 2018, 07:57:43 PM
I assume this is a technical problem, not real extent data right?

Title: Re: The 2018 melting season
Post by: Neven on April 23, 2018, 07:58:43 PM
If you see a similar thing on the Antarctic graph, it's almost certainly technical in nature.  ;)
Title: Re: The 2018 melting season
Post by: Wherestheice on April 23, 2018, 08:25:13 PM
I assume this is a technical problem, not real extent data right?

may I ask where you got that graph?
Title: Re: The 2018 melting season
Post by: Sarat on April 23, 2018, 08:37:15 PM
(Maybe off topic to continue in this thread, apologies)

This looks like AMSR2 satellite issue hopefully not a permanent one, all AMSR2 graphs/maps are affected by large swaths of missing data.

See here:
https://seaice.uni-bremen.de/sea-ice-concentration/
Title: Re: The 2018 melting season
Post by: gerontocrat on April 23, 2018, 08:54:16 PM
(Maybe off topic to continue in this thread, apologies)

This looks like AMSR2 satellite issue hopefully not a permanent one, all AMSR2 graphs/maps are affected by large swaths of missing data.

See here:
https://seaice.uni-bremen.de/sea-ice-concentration/
I would not be surprised if JAXA has to go on holiday for a bit.
I have a horrible memory of a discussion some time back about how the satellites (AMSR2 and the USAF one feeding NSIDC) are operating well beyond their design life without replacements in the pipeline.
Ho hum.
Title: Re: The 2018 melting season
Post by: A-Team on April 23, 2018, 10:12:20 PM
I asked Dr. P Chang of NOAA today why so many swaths on ASCAT have been blacked out for 4-5 days (similar to but different than AMSR2).

He said there were no problems with the satellite nor its instrument but that "it’s a network connectivity issue between eumetsat and NOAA...instrument is still healthy.... If we have the data we can recreate the images...I asked my folks to do that".

The Eumetsat home page that operates this satellite is serving a truly crappy dumbed-down version of the data that cannot serve as replacement for NOAA's secondary version.

How long did Eumetsat plan to let the glitch run before fixing the network connectivity issue? Does Eumetsat plan to repair the damage by resending the data? How long has NOAA been aware of this problem prior to my email?

Meanwhile, all these satellite time series have glitches from time to time. I've explored various technical fixes in the past, such as layering up the defective image over the previous day, deleting the bad swaths to transparency using a color picker, capturing show-through along with the good parts of the bad image, and replacing it.

There's a cross-platform variation on this that stubs in a grayscale from another satellite for the missing pieces, say Jaxa, which so far has been unaffected. That is doable but much more complex because of scaling, swath timing and correlative tonal matching. It does put in real contemporaneous data unlike putting the previous day but then again it's not scatterometer data.

*/*/*/

Update: NOAA was able to repair days 111 and 112 but not the three previous. Day 113 is not available yet, about 6 hours late. [Update: it has appeared, about 18 hours late. Update: day 114 arrived on schedule, minor problems with it indicating the "network connectivity issue between eumetsat and NOAA" is still not repaired.]

Actually very little has happened in terms of ice movement.

Scrolling out five days in nullschool GFS pressure and wind, a slight low cuts itself off from a larger Siberian feature and drifts aimlessly across the central Arctic. Winds will be incoherent at a reglional level except westward along the Alaskan coast.

OSI-SAF has not been able to repair their 3 blanked-out days, 10-12 April 2018. This may have a different explanation.

http://osisaf.met.no/p/osisaf_hlprod_qlook.php?year=2018&month=04&day=09&action=d%2B&prod=LR-Drift&area=NH&size=100%25

Checking UH AMSR2 to see if they have significant glitches, the answer is no for the month of April. Black-out wedges do occur from time to time; the archive is never repaired by management. These are largely peripheral and not as damaging as changes in pixel dimensions.

My theory is no one but us ever looks at the data as it comes in. It is all robotic pipeline from satellite to web archive. Once in a great while, maybe a researcher goes back and uses the archived imagery for a paper. Only then are gaps noticed. By that time, repairs won't be possible any longer.

There's too much reliance on robotics; it makes no economic sense given the expense of the satellite, the cheapness of an intern or elderly volunteer, and the value of a long time series.

Title: Re: The 2018 melting season
Post by: Neven on April 23, 2018, 10:38:18 PM
Thanks for asking, A-Team. I had noticed something was off with ASCAT yesterday.
Title: Re: The 2018 melting season
Post by: gerontocrat on April 23, 2018, 11:16:17 PM
I asked Dr. P Chang of NOAA today why so many swaths on ASCAT have been blacked out for 4-5 days (similar to but different than AMSR2).

He said there were no problems with the satellite nor its instrument

Always a relief to me when it is not a problem with what's up there. Or am I getting nervous unnecessarily?
Title: Re: The 2018 melting season
Post by: gerontocrat on April 23, 2018, 11:29:33 PM
I am giving my speculation of the relative importance of average temperature vs the much higher maximum daytime temperatures at high latitudes another airing.

The large contrast between the average and maximum temperatures  is illustrated in the two images below. The average image would suggest that the entire Arctic ocean is below zero.

The second image shows that maximum temperatures will be and have been well above freezing at various places on the fringes. Two places are highlighted in red, one in the middle of the Siberian Arctic coast and the other on the Alaskan side of the Chukchi.

The third image shows where there is open water - is it a coincidence that the two highlighted places on this image are the same ?

ps: with maximum temperatures like that, the snow is going to take a hammering even if it freezes at night.
Title: Re: The 2018 melting season
Post by: JayW on April 24, 2018, 12:11:50 AM
123 hour loop Chukchi sea.  I boosted the contrast slightly for detail.

http://feeder.gina.alaska.edu/npp-gina-alaska-truecolor-images?search%5Bfeeds%5D%5B5%5D=1&search%5Bsensors%5D%5B3%5D=1
Title: Re: The 2018 melting season
Post by: FishOutofWater on April 24, 2018, 02:10:09 AM
The open water on the north shore of Siberia did not show signs of refreezing in today's MODIS Worldview image. The offshore southerly winds that opened the polynya had temperatures around 0 C. When you consider that days are long now in the Arctic, this is not good news for the ice and snow. The good news is that it's colder than normal in the CAA.
Title: Re: The 2018 melting season
Post by: sedziobs on April 24, 2018, 02:27:52 AM
123 hour loop Chukchi sea.
Very cool to see new ice that forms each night vanish during daylight hours.
Title: Re: The 2018 melting season
Post by: oren on April 24, 2018, 03:00:55 AM
123 hour loop Chukchi sea.
Very cool to see new ice that forms each night vanish during daylight hours.
Yes. An animation is worth a thousand words. I noticed that the northern part managed to keep some ice cover, while the south (Kotzebue Sound) lost it completely each day. So in a few days of warming the northern part is bound to lose a chunk of extent.
Title: Re: The 2018 melting season
Post by: Thomas Barlow on April 24, 2018, 04:46:19 PM
I have a bad feeling about this.
http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

Title: Re: The 2018 melting season
Post by: jdallen on April 24, 2018, 08:12:25 PM
It all hinges very heavily on the next 8 weeks weather.  Not sure I can emphasize that enough. I do know that each year we start in a more difficult place vis-a-vis total heat in the system. That makes the weather more critical than any year in the record previously save the possible exception of 2013, while in ways we may be more vulnerable now.
Title: Re: The 2018 melting season
Post by: uniquorn on April 24, 2018, 08:44:47 PM
With favourable weather (for viewing) north of Greenland yesterday I thought I'd try to find visible signs of thicker ice north of the 'Kara tongue' using viirs. An ascat image of the 'Kara tongue' export is shown inset on the first two frames. I've squashed the palette in each zoom of the viirs image as far as possible to show detail around the boundary while minimising artifacts.
Not very conclusive, but the area on the left of the last frame does appear to show longer cracks and less refrozen fractures. Hopefully the ice is a bit thicker there.

ascat apr23
worldview terra/modis, viirs brightness temperature band 15, progressively squashed palette apr23
Title: Re: The 2018 melting season
Post by: dosibl on April 24, 2018, 08:48:48 PM
Jdallen (or others), with that in mind what are the key weather metrics we can keep an eye on over the next two months? Up-thread Neven and others have been noting the persistent high that is trying to set up shop, my recollection from last melting season is that a high pressure system can potentially lead to less clouds and more insolation, is that the main concern?

I know the various GACs (may not be the best term for them) from the past few years can really churn up the ice, but my understanding was that storms generally compact the ice and didn't really cause massive loss. Weaker ice may not hold up as well to storms, but from an ice-preservation standpoint I assume we'd rather have a stormy summer than a clear-sky summer. 
Title: Re: The 2018 melting season
Post by: numerobis on April 25, 2018, 01:29:48 AM
Neven is impressed by some research that shows melt ponds are the devil.

The argument is that if you have ponds of water forming on top of the ice, they can gather up a lot of heat and melt the ice from the top during the early summer (until the ice cracks and the ponds drain). That means more total solar heat absorbed over the summer, and conditions the remaining ice to melt faster.

And how do you make melt ponds? By shining the sun on the snow to melt it, but not breaking up the ice too early with a storm.

So that's why high pressure on the arctic, from the end of April to early June, seems bad.
Title: Re: The 2018 melting season
Post by: Juan C. García on April 25, 2018, 05:29:14 AM
Jdallen (or others), with that in mind what are the key weather metrics we can keep an eye on over the next two months? Up-thread Neven and others have been noting the persistent high that is trying to set up shop, my recollection from last melting season is that a high pressure system can potentially lead to less clouds and more insolation, is that the main concern?

On 2016, the Beaufort Gyre was very strong. That is why 2016 is still the lowest on record, on this time of the year.

http://neven1.typepad.com/blog/2016/05/beaufort-under-relentless-high-pressure.html (http://neven1.typepad.com/blog/2016/05/beaufort-under-relentless-high-pressure.html)
Title: Re: The 2018 melting season
Post by: slow wing on April 25, 2018, 06:48:04 AM
Neven is impressed by some research that shows melt ponds are the devil.

The argument is that if you have ponds of water forming on top of the ice, they can gather up a lot of heat and melt the ice from the top during the early summer (until the ice cracks and the ponds drain). That means more total solar heat absorbed over the summer, and conditions the remaining ice to melt faster.

And how do you make melt ponds? By shining the sun on the snow to melt it, but not breaking up the ice too early with a storm.

So that's why high pressure on the arctic, from the end of April to early June, seems bad.

 Yes, it is clear to me also that melt ponds can accelerate melt, for the physical reason given above and because liquid water absorbs shortwave solar energy so much better than ice or snow.

 I think it likely that a large part of the reason 2012 set the low extent record in September was the extraordinary fraction of Arctic sea ice covered in melt ponds during May & June - as was observable even from the satellite data.

 The part of your post where I haven't seen observational evidence is that the ice pack can be broken up by storms so much, over so much of the Arctic & as early as May or June, that melt ponds can't easily form.

 Has that been established? If so, could someone point out where please?

 In the central Arctic much of the ice will have a thickness in the range of roughly 1.5 to 2.5 meters and so a free board above the water level of a couple of tens of centimeters - say 20-30 cm. Can much of the 2 meter thick ice be broken up so small - presumably no more than meters across rather than tens of meters or larger - by storms in May or June?

 I would need to see some evidence for what runs counter to my mental picture that is based in part on photos of ice breakers & their trails, where the ice can look intact even when substantially thinner than that.

 Parenthetically, I also suspect that if sea ice is broken into transverse dimensions not much larger than its thickness - and so unable to form melt ponds - then it would melt out more quickly anyway due to all the exposed leads and to bobbing and rocking around. But I've only seen lake ice, not sea ice - so that is just a guess.
Title: Re: The 2018 melting season
Post by: litesong on April 25, 2018, 09:45:25 AM
I would need to see some evidence for what runs counter to my mental picture that is based in part on photos of ice breakers & their trails, where the ice can look intact even when substantially thinner than that.
NSIDC much declared the early August 2012 Arctic storm as the main contributor to 2012 minimum Arctic sea ice loss.
http://nsidc.org/arcticseaicenews/2012/08/
Follow-up information in September & October confirmed the August 2012 Arctic storm as the culprit. http://nsidc.org/arcticseaicenews/2012/09/
Title: Re: The 2018 melting season
Post by: Neven on April 25, 2018, 10:32:28 AM
NSIDC much declared the early August 2012 Arctic storm as the main contributor to 2012 minimum Arctic sea ice loss.
http://nsidc.org/arcticseaicenews/2012/08/
Follow-up information in September & October confirmed the August 2012 Arctic storm as the culprit. http://nsidc.org/arcticseaicenews/2012/09/

No, they didn't. Did you even read your own links?

Quote
While this drop coincided with an intense storm over the central Arctic Ocean, it is unclear if the storm prompted the rapid ice loss.

(...)

This could be due to mechanical break up of the ice and increased melting by strong winds and wave action during the storm. However, it may be simply a coincidence of timing, given that the low concentration ice in the region was already poised to rapidly melt out.

(...)

The most notable event was a very strong storm centered over the central Arctic Ocean in early August. It is likely that the primary reason for the large loss of ice this summer is that the ice cover has continued to thin and become more dominated by seasonal ice. This thinner ice was more prone to be broken up and melted by weather events, such as the strong low pressure system just mentioned. The storm sped up the loss of the thin ice that appears to have been already on the verge of melting completely.

If the ice hadn't been as pre-conditioned during May, June and July, the storm would have had much less of an effect. We haven't seen that level of pre-conditioning since.
Title: Re: The 2018 melting season
Post by: Neven on April 25, 2018, 10:48:33 AM
NH snow cover is suddenly falling off a cliff:
Title: Re: The 2018 melting season
Post by: uniquorn on April 25, 2018, 04:07:48 PM
With more warm temperature anomalies forecast over ess and laptev for the next few days, an animation of amsr2 for this melting season with today's worldview for comparison.

uni-hamburg amsr2 ice concentration for ess and laptev Mar21-Apr24.
Worldview terra/modis apr25

 
Title: Re: The 2018 melting season
Post by: numerobis on April 25, 2018, 05:15:58 PM
The part of your post where I haven't seen observational evidence is that the ice pack can be broken up by storms so much, over so much of the Arctic & as early as May or June, that melt ponds can't easily form.

You're right, that part I'm speaking beyond where I should have spoken.

It's clear that when the ice cracks, the melt ponds drain out. But that spring storms would cause those cracks, I don't have the data to prove.

Maybe look at Hudson Strait and the Baffin Sea this weekend? We're about to get a nice big storm.

EDIT: just checked the forecast better; we're expecting very strong winds tomorrow in Iqaluit due to a weak storm. It's forecast to come with a fair bit of snow, but the winds aren't that big overall -- they just happen to hit us just right.

A more powerful storm is forming up Sunday over the northern end of Hudson Bay. It should shake things a bit more.

Hudson Bay isn't super relevant to the ice up North of course, it's just a microcosm to study.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 25, 2018, 06:15:05 PM
SSBNs surfacing?

https://nypost.com/2018/04/24/scientists-cant-explain-these-mysterious-arctic-ice-circles/

(https://thenypost.files.wordpress.com/2018/04/180424-mystery-ice-circles-feature-1.jpg?quality=90&strip=all&w=1236&h=820&crop=1)
Title: Re: The 2018 melting season
Post by: Andreas T on April 25, 2018, 06:31:47 PM
Neven is impressed by some research that shows melt ponds are the devil.

The argument is that if you have ponds of water forming on top of the ice, they can gather up a lot of heat and melt the ice from the top during the early summer (until the ice cracks and the ponds drain). That means more total solar heat absorbed over the summer, and conditions the remaining ice to melt faster.

And how do you make melt ponds? By shining the sun on the snow to melt it, but not breaking up the ice too early with a storm.

So that's why high pressure on the arctic, from the end of April to early June, seems bad.
repeating some stuff from previous discussions because this keeps coming up:
It is worth looking at the mechanisms by which ponds accelerate melt, rather than just repeat the shorthand "meltponds absorb"
The ponds are darker in colour because much of the light passes through the clear water in the pond and the fairly translucent ice floe into the ocean below and doesn't come back out again.
Absorption therefore takes place mostly in the ice (especially if there are algae present) and in the ocean, not so much in the water in the pond.
Snow reflects sunlight so the best way to melt it is to blow warm air over it (especially if its also moist) rain would be best.
This comes with low pressure rather than high pressure which at the lower sun angle in April looses more outgoing radiation through clear sky than it gains.
Title: Re: The 2018 melting season
Post by: FishOutofWater on April 25, 2018, 06:40:24 PM
There's a big difference between the sun angle at the north shore of Alaska and at the north pole in late April. Moreover, we have seen a dipole with low pressure on the Siberian side of the Arctic ocean and high pressure on the Canadian side. Oversimplification does not make for a cogent analysis of how the weather is impacting sea ice this spring.

The blue areas north of Siberia in the imagery shown a few posts above indicate areas of possible melting. That is not a good sign for sea ice longevity on the Siberian side of the Arctic ocean.
Title: Re: The 2018 melting season
Post by: uniquorn on April 25, 2018, 07:29:14 PM
With even more warm temperature anomalies forecast over bering and chukchi for the next few days, an animation of amsr2 for this melting season.

Light blue areas normally indicate lower concentration but may also be due to cloud cover (imho).

uni-hamburg amsr2 ice concentration for bering and chukchi Mar21-Apr24.
Title: Re: The 2018 melting season
Post by: uniquorn on April 25, 2018, 08:59:20 PM
I wasn't going to post amsr2 of the atlantic side but do so in memory of the plucky floe that almost made it across the nth of Svalbard 'killing zone' earlier this month.
Worldview confirms the attempt in the second animation (marked with an X in the first frame). Interesting to see how fragile the refreeze between the floes is in this area.

uni-hamburg amsr2 ice concentration for kara and barents Mar21-Apr24
Worldview terra/modis mar28-apr9
Title: Re: The 2018 melting season
Post by: oren on April 25, 2018, 09:46:54 PM
I wasn't going to post amsr2 of the atlantic side but do so in memory of the plucky floe that almost made it across the nth of Svalbard 'killing zone' earlier this month.
Worldview confirms the attempt in the second animation (marked with an X in the first frame). Interesting to see how fragile the refreeze between the floes is in this area.
Great animation. The heat content of that area is amazing. Latitude above 81oN in April, healthy-looking floes constantly exported into it, all melting quickly leaving no trace. Atlantification completed.
Title: Re: The 2018 melting season
Post by: jdallen on April 25, 2018, 10:48:34 PM
Neven is impressed by some research that shows melt ponds are the devil.

<snippage>

So that's why high pressure on the arctic, from the end of April to early June, seems bad.
Neven is right, and high pressure and full unfiltered sunlight is unambiguously bad for the Arctic regardless of snow cover.

To an earlier question - the things to watch are albedo and SST  I think.  Those will suggest to us how much insolation is being taken up, and how much heat is available to be applied to the ice.
Title: Re: The 2018 melting season
Post by: jdallen on April 25, 2018, 10:55:07 PM
With more warm temperature anomalies forecast over ess and laptev for the next few days, an animation of amsr2 for this melting season with today's worldview for comparison.

uni-hamburg amsr2 ice concentration for ess and laptev Mar21-Apr24.
Worldview terra/modis apr25

I've been distracted for a few days, but started noticing this in my semi-daily surveys of Worldview.  I'm not sure if it qualifies yet as an early start, but the timing combined with clear skies isn't helpful.
Title: Re: The 2018 melting season
Post by: Michael Hauber on April 26, 2018, 01:21:41 AM

 I think it likely that a large part of the reason 2012 set the low extent record in September was the extraordinary fraction of Arctic sea ice covered in melt ponds during May & June - as was observable even from the satellite data.

 The part of your post where I haven't seen observational evidence is that the ice pack can be broken up by storms so much, over so much of the Arctic & as early as May or June, that melt ponds can't easily form.


As far as I know there is no good satellite observation of melt pond data showing the amount of surface melt ponding in May/June 2012 vs other years.  The paper on melt ponding that made a big impression in this forum was based on modelled melt pond formation, not observations.  From  a subjective eyeball assessment of the amount of red in channel 3-6-7 images on MODIS I'd say 2012 had high surface melt ponding, but not as high as 2016.

My opinion is that breaking up the ice pack with a storm does more damage than melt ponds.  In visible images melt ponds are hard to see without the 3-6-7 filters that show them up red.  But gaps between the ice are appear very much darker (but satellite viewing angle compared to solar incident angle may change the difference in darkness).  I'd suspect a lot more energy is absorbed by patches of water mixed in  with the ice following a storm than are absorbed by melt ponds, and that this energy will be transferred to the ice by melt season end.  In 2012 there was a moderate and short lived storm in late June, after which large areas of the Arctic became somewhat dispersed with patches of open water mixed in.  These areas steadily got worse throughout the season until they were very fragile prior to the early August storm which finished the job.  Constant storms such as 2013 means a disperse pack with lots of water to absorb solar energy, but a serious shortage of solar energy to be absorbed.  Short periods of storminess followed by long periods of sunny is the ideal melting recipe in my opinion.
Title: Re: The 2018 melting season
Post by: wallen on April 26, 2018, 04:24:05 AM
Many comments abound regarding the Fram export each year, but I have just been looking at the waters between Svalbard and Franz Josef Land. To me the ice looks in very poor state and I am wondering if it does melt out there, what possible effect it could have for the rest of the melt season.
Title: Re: The 2018 melting season
Post by: romett1 on April 26, 2018, 09:25:55 AM
Models are now predicting warm weather over Northern Greenland starting around May 02 (image). Next week could be interesting. Image: https://www.tropicaltidbits.com/analysis/models/
Title: Re: The 2018 melting season
Post by: litesong on April 26, 2018, 09:54:28 AM
No, they didn't. Did you even read your own links?

Quote
While this drop coincided with an intense storm over the central Arctic Ocean, it is unclear if the storm prompted the rapid ice loss......
The most notable event was a very strong storm centered over the central Arctic Ocean in early August. It is likely that the primary reason for the large loss of ice this summer is that the ice cover has continued to thin and become more dominated by seasonal ice. This thinner ice was more prone to be broken up and melted by weather events, such as the strong low pressure system just mentioned.
I read the links when they were made in 2012, over & over.  I read the links often in succeeding years. Just before I mentioned these links, I read them over & over, again. It was the storm that busted up the thin ice & helped flush the ice to the south... with wind differently directed from the norm, also.
Not till mid to latter June did 2012 Arctic sea ice really start to drop, altho not much more than previous years. It was near August that the fame of 2012 Arctic sea ice really parted itself from all years previously AND ALL YEARS AFTER 2012.
I stand by my statement that the storm really busted the ice & believe the storm set up wind directions that easily transported busted ice out of the Arctic.
 
 

Title: Re: The 2018 melting season
Post by: Neven on April 26, 2018, 10:01:47 AM
I stand by my statement that the storm really busted the ice & believe the storm set up wind directions that easily transported busted ice out of the Arctic.

It's fine for you to stand by your statement, but don't say that the NSIDC stated the same.
Title: Re: The 2018 melting season
Post by: VeliAlbertKallio on April 26, 2018, 12:13:56 PM
Citing from the Arctic News:

Sam Carana Admin · 24 April at 02:29: "Something appears to be wrong with the Arctic sea ice extent chart at the University of Bremen, Germany. The chart shows a sharp fall of extent that isn't matched by other websites that track extent."

Sam Carana: "I received a kind email from Gunnar Spreen, Ph.D., University of Bremen - Institute of Environmental Physics, who explains the glitch:"

"Dear Sam Carana,

Thank you for informing us about the problem. The anomaly you are seeing is a glitch in the processing. As you can see from the sea ice concentration map on our webpage seaice.uni-bremen.de not all data was available yesterday. This caused large gaps in the sea ice area, which caused the sea ice extent to drop artificially. We are investigating the causes and will update the graph as soon as we can. I will let you know when the problem is resolved.
I am sorry for the inconvenience and thank you for your interest in our products.

Best wishes,
Gunnar"

I assume this is a technical problem, not real extent data right?
Title: Re: The 2018 melting season
Post by: Daniel B. on April 26, 2018, 02:33:36 PM
No, they didn't. Did you even read your own links?

Quote
While this drop coincided with an intense storm over the central Arctic Ocean, it is unclear if the storm prompted the rapid ice loss......
The most notable event was a very strong storm centered over the central Arctic Ocean in early August. It is likely that the primary reason for the large loss of ice this summer is that the ice cover has continued to thin and become more dominated by seasonal ice. This thinner ice was more prone to be broken up and melted by weather events, such as the strong low pressure system just mentioned.
I read the links when they were made in 2012, over & over.  I read the links often in succeeding years. Just before I mentioned these links, I read them over & over, again. It was the storm that busted up the thin ice & helped flush the ice to the south... with wind differently directed from the norm, also.
Not till mid to latter June did 2012 Arctic sea ice really start to drop, altho not much more than previous years. It was near August that the fame of 2012 Arctic sea ice really parted itself from all years previously AND ALL YEARS AFTER 2012.
I stand by my statement that the storm really busted the ice & believe the storm set up wind directions that easily transported busted ice out of the Arctic.

Both likely combined to result in the rapid ice loss.  Looking at the NSIDC data, the winter maximum in 2012 was the second highest since 2003 (only 2008 being higher), and remaining high until the beginning of June (passing 2008 and 2002).  Over the next two weeks, the Arctic lost an incredible amount of ice, dropping 2012 to the second lowest extent on record (2016 being lowest).  The melt from there was fairly routine, until the end of July.  Then the August storm took over, breaking up the ice, resulting in a new record low.  While the drop from the beginning of August to the September low was the largest on record, it was only 8% greater than the 2008 drop.  Indeed, had the ice began August at the same level as 2008, the ice loss would have only dropped 2012 to 4th lowest.  Hence, the combination of the two melts yielded the record low.
Title: Re: The 2018 melting season
Post by: litesong on April 26, 2018, 04:36:18 PM
I stand by my statement that the storm really busted the ice & believe the storm set up wind directions that easily transported busted ice out of the Arctic.

It's fine for you to stand by your statement, but don't say that the NSIDC stated the same.
Michael Hauber says:
......My opinion is that breaking up the ice pack with a storm does more damage than melt ponds...... I'd suspect a lot more energy is absorbed by patches of water mixed in  with the ice following a storm than are absorbed by melt ponds, and that this energy will be transferred to the ice by melt season end.  In 2012 there was a moderate and short lived storm in late June.....  These areas steadily got worse throughout the season until they were very fragile prior to the early August storm which finished the job.....Short periods of storminess followed by long periods of sunny is the ideal melting recipe in my opinion.
Title: Re: The 2018 melting season
Post by: jdallen on April 26, 2018, 05:12:48 PM
I stand by my statement that the storm really busted the ice & believe the storm set up wind directions that easily transported busted ice out of the Arctic.

It's fine for you to stand by your statement, but don't say that the NSIDC stated the same.
Michael Hauber says:
......My opinion is that breaking up the ice pack with a storm does more damage than melt ponds...... I'd suspect a lot more energy is absorbed by patches of water mixed in  with the ice following a storm than are absorbed by melt ponds, and that this energy will be transferred to the ice by melt season end.  In 2012 there was a moderate and short lived storm in late June.....  These areas steadily got worse throughout the season until they were very fragile prior to the early August storm which finished the job.....Short periods of storminess followed by long periods of sunny is the ideal melting recipe in my opinion.
We should take this discussion to "chatter" as we are discussing past years and specific mechanisms.  I tend to agree with Neven.
Title: Re: The 2018 melting season
Post by: Sebastian Jones on April 26, 2018, 06:11:26 PM
The record early ice loss in the Bering Sea is expected to continue as the Chukchi and the Beaufort start to melt. However the NWS long range forecast is that once the early melt of thin ice is done, melt will stall:

As we look forward to break-up through July, we expect to continue
to see a remarkably early break-up through the southern Chukchi Sea.
Farther north toward the multi-year ice, break-up is expected to be
significantly slower than locations to the south (and slower than
2017) due to the time it will take to melt the multi-year ice in the
area. The Beaufort Sea will likely see ice break up from the Alaska
coast northward as is common, however we expect to see the main ice
pack melt at a much slower rate than last year due to the much more
widespread multi-year ice that remains throughout much of the
Beaufort Sea this year.


Detailed information can be found in each pertinent section below.

This is the NWS 3 month forecast, and like all long range forecasts, is typically "wrong" and almost always conservative.
http://tgftp.nws.noaa.gov/data/raw/fz/fzak30.pafc.ico.afc.txt (http://tgftp.nws.noaa.gov/data/raw/fz/fzak30.pafc.ico.afc.txt)
Title: Re: The 2018 melting season
Post by: jdallen on April 26, 2018, 08:11:05 PM
The record early ice loss in the Bering Sea is expected to continue as the Chukchi and the Beaufort start to melt. However the NWS long range forecast is that once the early melt of thin ice is done, melt will stall:

<snippage>

This is the NWS 3 month forecast, and like all long range forecasts, is typically "wrong" and almost always conservative.
http://tgftp.nws.noaa.gov/data/raw/fz/fzak30.pafc.ico.afc.txt (http://tgftp.nws.noaa.gov/data/raw/fz/fzak30.pafc.ico.afc.txt)
Considering the current administration's pressure on the EPA I'm not surprised. Considering the weakness of that "multi year ice" I think if they consider their statement seriously they are whistling in the dark.
Title: Re: The 2018 melting season
Post by: A-Team on April 26, 2018, 09:16:34 PM
Let's be clear that this is just the distant Anchorage office forecast for US bays and coastal waters off Alaska. It is not a melting season forecast for the Arctic Ocean. It comes not from NOAA but a sub-agency NWS (formerly the Weather Bureau). Both are part of the US Dept of Commerce, with former Trump casino bankruptcy restructuring savior Wilbur Ross, 81, the current Secretary.

You can recognize NWS news releases at a glance: 8-point typewriter font awash in ALL CAP HEADERS with no graphics, continuing a proud tradition that began in 1870. Courier font is much better suited for distribution by telegraph* than maps or satellite imagery. NWS relies more on local weather knowledge of old hands than coupled computer models that risk introduction of the metric system:

"For Cape Krusenstern to Point Hope to 20 NM [[nautical miles]] offshore, sea ice is  expected to move away from the coast occasionally with northerly to  easterly winds, but will likely move back toward the coast during times of southerly winds."

* a system for transmitting messages from a distance along a wire, especially one creating signals by making and breaking an electrical connection.

The go-to forecaster for off-shore Alaska conditions, forecasts and history is Rick Thoman of NOAA. His twitter and climate.gov sites are two of the best:

https://twitter.com/AlaskaWx
https://www.climate.gov/author/rick-thoman

Note the very useful graphic below uses the Fahrenheit scale! Here Kotzbue is on that big bay north of the Bering Strait, Utqiagvik was called Barrow, and Deadhorse is ~ Prudhoe Bay.
Title: Re: The 2018 melting season
Post by: Thomas Barlow on April 26, 2018, 09:24:12 PM
Meanwhile, the 2018 melting season on Mars may have stalled.
"Lead researcher Nicolas Thomas said Thursday the colors in the resulting image were also adjusted to best resemble those visible to the human eye."

'European Space Agency Releases 1st Image From Mars Orbiter'
"The European Space Agency has released its first image taken by a probe orbiting Mars, showing the ice-covered edge of a vast crater."
https://www.nbcwashington.com/news/tech/European-Space-Agency-Releases-1st-Image-From-Mars-Orbiter-480953601.html
Title: Re: The 2018 melting season
Post by: Neven on April 26, 2018, 09:45:35 PM
The ECMWF forecast (as provided by Tropical Tidbits (https://www.tropicaltidbits.com/analysis/models/?model=ecmwf&region=nhem&pkg=z500_mslp&runtime=2018032900&fh=24)) shows high pressure staying put over the CAB, but not nearly as strong as it was until recently. The AO Index points to this situation probably continuing into May. The big question, to me right now, is how clear skies will be during May.
Title: Re: The 2018 melting season
Post by: gerontocrat on April 26, 2018, 10:02:52 PM
Whoops
Title: Re: The 2018 melting season
Post by: Greenbelt on April 26, 2018, 10:18:17 PM
In the longer run, both GFS and ECMWF bring surface high pressure to the Barents Sea as well.
EDIT -- sorry I see now off the right side of Neven's prior image post also shows this, sorry for redundant
(https://www.tropicaltidbits.com/analysis/models/gfs/2018042612/gfs_z500_mslp_nhem_29.png)
Title: Re: The 2018 melting season
Post by: JayW on April 27, 2018, 12:44:16 AM
April 23-26, 2018, 78 hour loop of the Beaufort Sea.  Doubt there is much melting, but certainly a fair amount of wind driven displacement.

Contrast slightly increased for detail.

http://feeder.gina.alaska.edu/npp-gina-alaska-truecolor-images?page=3&search%5Bfeeds%5D%5B5%5D=1&search%5Bsensors%5D%5B3%5D=1
Title: Re: The 2018 melting season
Post by: oren on April 27, 2018, 03:04:36 AM
April 23-26, 2018, 78 hour loop of the Beaufort Sea.  Doubt there is much melting, but certainly a fair amount of wind driven displacement.
My concern is there doesn't seem to be much refreezing going on in the opened cracks.

Elsewhere in the Arctic, we have been hearing that Fram export is quite low these days. The anomalously low ice area reported for the Greenland Sea certainly support this notion, but a look at the Barents shows IMHO that the export machine is humming but has just changed direction.
The same conclusion seems to be supported by the north-of-Svalbard ice killing zone, which gets vigorous imports into it.
Title: Re: The 2018 melting season
Post by: jdallen on April 27, 2018, 03:50:04 AM
April 23-26, 2018, 78 hour loop of the Beaufort Sea.  Doubt there is much melting, but certainly a fair amount of wind driven displacement.

<snip>
It's a non-trivial decrease in Albedo is what it is... aside from the fragmentation of the ice that is taking place.
Title: Re: The 2018 melting season
Post by: bbr2314 on April 27, 2018, 08:15:29 AM
We are about where we were one month ahead of now in May of 2016 as of 4/26/2018, at least on the Pacific front. See 5/26/2016 vs. 4/26/2018 (2018 is much brighter, more snow)

(https://media.giphy.com/media/1SCDjiLVlHInz8Rla3/giphy.gif)

I think this is important to note because May of 2016 saw the massive event in the Beaufort, but that kind of absorbed the "shock" of the heat that month and the Bering front advanced more slowly. The opposite is happening this year -- the Bering front has now broadened to encompass a much larger swath of entry, and the Beaufort shock capacity has been reduced by its massive decrease in volume. The Beaufort will still melt out all the same but it will go poof instead of isolating into Big Blocks (maybe a few "feeble floes").

IMO this comparison and the D10 forecast from the models portends a disastrous June over the Beaufort / Siberian Seas / peripheral CAB. It will basically look like 2016 but with one extra month of peak insolation on top. I expect we see a record minimum extent and area this year. The amount of heat incoming from both the ATL and the PAC is simply overwhelming everything else.
Title: Re: The 2018 melting season
Post by: JayW on April 27, 2018, 12:24:34 PM
April 23-26, 2018, 78 hour loop of the Beaufort Sea.  Doubt there is much melting, but certainly a fair amount of wind driven displacement.

<snip>
It's a non-trivial decrease in Albedo is what it is... aside from the fragmentation of the ice that is taking place.

I agree. According to the ECMWF (and largely agreed upon by other models), the easterly winds north of Alaska are progged to pick up over the next 24-36 hours and persist for the next four days.  Forecast skill decreases rapidly, so I won't speculate beyond that, but it suggests the "rifting" in the Beaufort should continue in the near future.

https://weather.us/model-charts/euro/north-pole/wind-mean-direction/20180503-0000z.html
Title: Re: The 2018 melting season
Post by: gerontocrat on April 27, 2018, 02:59:46 PM
The little table below is calculated from NSIDC regional Sea total change LESS Hudson and Okhotsk.
I did this as many regard both of those seas as physically separate from the main Arctic Ocean.

If one does that little bit of arithmetic it seems area loss reversed recently into area gain.

Area Change excluding Okhotsk and Hudson in Km2
18-Apr   -24,251
19-Apr   -29,493
20-Apr   -24,356
21-Apr    76
22-Apr    2,531
23-Apr   -190
24-Apr    12,677
25-Apr    10,548
26-Apr    5,304
Title: Re: The 2018 melting season
Post by: Sterks on April 27, 2018, 08:32:47 PM
The ECMWF forecast (as provided by Tropical Tidbits (https://www.tropicaltidbits.com/analysis/models/?model=ecmwf&region=nhem&pkg=z500_mslp&runtime=2018032900&fh=24)) shows high pressure staying put over the CAB, but not nearly as strong as it was until recently. The AO Index points to this situation probably continuing into May. The big question, to me right now, is how clear skies will be during May.

And how will clear skies during May, may they come, affect the land? Rutgers' land snow cover departure suggests average advance of the snow "melt wave" (or better "melt front") over the big extents in Russia and Canada. A bit more delayed in the American continent but it seems to be catching up with climatological average, which is still "cold", compared to the past 10 years except 2017. 
Title: Re: The 2018 melting season
Post by: Niall Dollard on April 27, 2018, 10:45:45 PM
Two animations of worldview (satellite) and Norwegian Met Ice charts, show that the open water to the north of Svalbard has decreased in size between 17 and 26 April.

This may seem contrary to the images posted by Uniquorn earlier - but such are the vagaries of ice movement/export.
Title: Re: The 2018 melting season
Post by: Hyperion on April 28, 2018, 10:09:02 AM
Two animations of worldview (satellite) and Norwegian Met Ice charts, show that the open water to the north of Svalbard has decreased in size between 17 and 26 April.

This may seem contrary to the images posted by Uniquorn earlier - but such are the vagaries of ice movement/export.
But has it?
Perhaps being a bit of of a pederist but although the area of ocean with no ice may have increased, the fragmentation that caused this has produced an area with much less than full areal concentration. And flung the shrapnel well into the high SST kill zone. The latent heat absorbed by this ice committing hari-kari may buffer the high Arctic pack. But it's the blanket unraveling at the end of the day.

BTW Niall. Can you possibly datestamp the images you make gifs from? It makes it much easier to understand what you are looking at if you know the  chronology.
Title: Re: The 2018 melting season
Post by: binntho on April 28, 2018, 10:45:08 AM
Perhaps being a bit of of a pederist ...

I hope not! You probably meant being a bit pedantic?
Title: Re: The 2018 melting season
Post by: romett1 on April 28, 2018, 12:50:41 PM
Heat travelling towards North Pole from the Atlantic side - May 02 - May 07 forecast. Images: https://www.tropicaltidbits.com/analysis/models/
Title: Re: The 2018 melting season
Post by: Alexander555 on April 28, 2018, 01:12:21 PM
I think it would be normal if their would be some extra ice north of Svalbard. Because there is a flow of warm water in that area. Otherwise it would not stay open the entire winter at a point so close to the North pole. And that flow is somewhere now at it's coldest point. If there is no extra ice now, it want be for this year.
Title: Re: The 2018 melting season
Post by: Hyperion on April 28, 2018, 01:53:17 PM
Perhaps being a bit of of a pederist ...

I hope not! You probably meant being a bit pedantic?
Gotcha!  ;)
Title: Re: The 2018 melting season
Post by: uniquorn on April 28, 2018, 03:03:59 PM
Two animations of worldview (satellite) and Norwegian Met Ice charts, show that the open water to the north of Svalbard has decreased in size between 17 and 26 April.
This may seem contrary to the images posted by Uniquorn earlier - but such are the vagaries of ice movement/export.
Sorry if my images gave that impression. I thought amsr2 clearly showed the ice front moving toward Svalbard.
The worldview animation was to track the plucky flow which zoomed around the 'killing ground', though it does also show the speed at which individual floes are melting.
Here is a closer look from amsr2 uni-hamburg for this melting season.
Title: Re: The 2018 melting season
Post by: oren on April 28, 2018, 03:19:15 PM
Thanks for the animation. I think it would be more accurate to say that the ice front north of Svalbard (on the left of the animation) advanced significantly on the last days of March, and has been stable since. On the other hand, the north-east front (at the top of the animation) has been slowly advancing during April, and made a big advance in the last few days.
Title: Re: The 2018 melting season
Post by: uniquorn on April 28, 2018, 04:18:41 PM
With warm winds forecast for the Greenland sea next week, an animation for Baffin and Greenland seas for this melting season with yesterdays worldview for comparison.

uni-hamburg amsr2 ice concentration for Baffin and Greenland seas Mar21-Apr27.
Worldview terra/modis apr27
Title: Re: The 2018 melting season
Post by: Shared Humanity on April 28, 2018, 04:21:56 PM
The ice is advancing rapidly but this is transport towards the Fram and, unless my eyes are deceiving me, the leading edge of the ice front is suffering from extensive melt.
Title: Re: The 2018 melting season
Post by: Niall Dollard on April 28, 2018, 04:27:45 PM
But has it?
The latent heat absorbed by this ice committing hari-kari may buffer the high Arctic pack. But it's the blanket unraveling at the end of the day.

BTW Niall. Can you possibly datestamp the images you make gifs from? It makes it much easier to understand what you are looking at if you know the  chronology.

The Norwegian Met also produce a sea ice area chart for Svalbard (attached). Currently standing at  391,000 km2 which is its peak so far this year. Ice area has been rising through April. The storms earlier in the year had a big impact on ice area. We saw the edge torn apart in February with a large open area to the north of the islands. I think this graph really shows how much the ice has been ravaged in this area through winter storms surges and warm currents.

It is more difficult to pick out some of the thinner ice on the satellite images, which is why I put up the ice chart images also. The ice edge is more or less the same to the NW of Spitsbergen Island with typical NE to SW movement of the ice into the Fram Strait. Over at the island to the NE of Sptizbergen (Nordaustlandet) ice has moved across westwards from the east to run along the north coast of that island. In addition the main fragmented pack edge has drifted a little further south to almost meet up with the ice north of Nordaustlandet.

Looking at the SSTs in the area north of Sptizbergen on the Norwegian Ice charts it shows that SSTs have been dropping a little over the passed 2 months. 27th April shows it between 0 and 2 C, 27th March has a small area > 2C and 27th Feb has a much larger area > 2C.

It is possible the overall pack edge moves further south as part of a more general movement of the pack away from the Pacific side and down over the Atlantic side. But of course that would ultimately condemn more ice for final melt out via the Fram Strait.

Re date stamps. I did date the first date of the animations and the last date of the animations, at the top left, but maybe they were scrolling too quickly.  :) 

@ Uniquorn. No I wasn't trying to nit pic your images. It is always worthwhile to track individual chunks and see where they end up !
Title: Re: The 2018 melting season
Post by: Thomas Barlow on April 28, 2018, 04:48:59 PM
This seems significant in the 2018 melting season, in case anyone missed it.

Russian North Pole camp - 12 days only were achieved due to instability of ice. Shortest by far I think? And I don't think they landed a cargo plane as they usually do (just helicopters and parachutists).
Is it just anecdotally interesting, or does it fit in as an example of the overall state of the Arctic Ocean icepack?

https://forum.arctic-sea-ice.net/index.php/topic,2290.msg151807.html#msg151807
Title: Re: The 2018 melting season
Post by: Shared Humanity on April 28, 2018, 05:08:29 PM
The overall state of the ice pack is highly fractured and mobile. While we follow closely the SIE and SIA measures, this new physical state of the ice pack has been, IMHO, permanently set in place. There is no going back to the large rafts of thick, ridged, MYI.
Title: Re: The 2018 melting season
Post by: jdallen on April 28, 2018, 07:31:40 PM
The overall state of the ice pack is highly fractured and mobile. While we follow closely the SIE and SIA measures, this new physical state of the ice pack has been, IMHO, permanently set in place. There is no going back to the large rafts of thick, ridged, MYI.
There are additional factors in play here as well. It is not just ice age or thickness, but strength as well.

A non-visible effect of the increased heat is significant loss of compressive strength of the ice.  Ice at -10C has 1/5th the strength of that at -20 and degrades further from there.  This means the ice even if thick simply does not have the strength to support larger rafts as it cannot resist the forces being applied to it.

As such, we see more fracturing and smaller average floe sizes as a result.  This translates further into more mobility and less resistance to weather, and once a small enough size is reached = about ~100M or so - side melt becomes a significant contribution to volume loss.

https://link.springer.com/article/10.1023%2FA%3A1021134128038
Title: Re: The 2018 melting season
Post by: charles_oil on April 28, 2018, 08:12:13 PM


Thomas - see the Barneo 2018 thread for the dates... & the (few) posts provided during the season.

Separately it looks like there is a Russian ship being commissioned to replace the floating camp in the future - so another victim of warming. See my post in 2018 North Pole Expeditions thread #14 March 30th.

Title: Re: The 2018 melting season
Post by: Pmt111500 on April 28, 2018, 08:17:53 PM
The overall state of the ice pack is highly fractured and mobile. While we follow closely the SIE and SIA measures, this new physical state of the ice pack has been, IMHO, permanently set in place. There is no going back to the large rafts of thick, ridged, MYI.
Yep, no solid pieces of MYI left thus the optimal model could simplify to something with icebergs from Greenland and 1 and 2-year ice. MYI is almost irrelevant nowadays.
Title: Re: The 2018 melting season
Post by: uniquorn on April 28, 2018, 09:33:22 PM
uni-hamburg amsr2 and dmi ice temperature for the current melting season Mar21-Apr27
Title: Re: The 2018 melting season
Post by: Dharma Rupa on April 28, 2018, 10:22:25 PM
The mean seems to have become the minimum.
Title: Re: The 2018 melting season
Post by: uniquorn on April 28, 2018, 10:41:28 PM
The ice close to CAA and the string of floes making their way round the Beaufort are MYI. I'm not sure how much of the rest is.
Ascat melting season day78-116.
(hopefully one of us will volunteer to check ascat every day)

technical notes:
imagej: brightness/contrast 43,255 (some loss) CLAHE 63,255,2.2
gimp: duplicate last frames, scale to 700, delay 250
thanks to A-team for graphics tips
Title: Re: The 2018 melting season
Post by: uniquorn on April 29, 2018, 12:27:51 AM
Heat travelling towards North Pole from the Atlantic side - May 02 - May 07 forecast. Images: https://www.tropicaltidbits.com/analysis/models/
yikes, another zero fram export event?
edit: maybe the models are confused.
Title: Re: The 2018 melting season
Post by: Telihod on April 29, 2018, 10:32:22 AM
Is the temperature anomaly difference in the Labrador Sea caused by the different baselines (NOAA and Climate Reanalyzer)?
Title: Re: The 2018 melting season
Post by: subgeometer on April 29, 2018, 12:17:16 PM
The mean seems to have become the minimum.

In recent years this is the point in the spring where80N temps can drop below the line, a period until the start of refreze, as in 2017.

Its going to spike again this year tho, GFS on Climate Analyser is showing a huge Atlantic heat intrusion starting about 3 days out and continuing until forecast end. The chart will go to maybe -5C if the forecast is to be believed, and remain there for days/ The pole will enjoy periods above freezing . The ECWMf forecast on windy tv is not quite extreme but shows a similar pattern of warm southerly winds on the Atlantic side, spreading to the Kara sea later
Title: Re: The 2018 melting season
Post by: uniquorn on April 30, 2018, 12:43:28 PM
Beaufort Sea yesterday.

Worldview terra/modis, viirs brightness temperature band 15,night
Title: Re: The 2018 melting season
Post by: Gray-Wolf on April 30, 2018, 05:05:50 PM
I'll bring this here from the area/extent thread.
The crux being that April melt does not give any feel for the minimum?
The degradation of the ice across Beaufort, currently ongoing, will surely have impact on the rest of the melt season bringing a more mobile pack and areas of dark water to harvest any incoming solar?
The 'stall' in ice loss is probably an illusion with fragmented ice filling in open water so fooling the 15% or more measure into seeing ice gain where none is occurring?

My thoughts are " your old road is rapidly changing" and that things we once held as true may no longer necessarily be so? The rapidity of ice breakup and reduction in floe sizes must have some say in how fast that ice melts out under good melt conditions?
If we keep on with HP dominance across the basin we might witness a start to the season not seen since 2012 and the ice then , I believe, will have been more resilient to today's?
Title: Re: The 2018 melting season
Post by: Daniel B. on April 30, 2018, 06:13:28 PM
I'll bring this here from the area/extent thread.
The crux being that April melt does not give any feel for the minimum?
The degradation of the ice across Beaufort, currently ongoing, will surely have impact on the rest of the melt season bringing a more mobile pack and areas of dark water to harvest any incoming solar?
The 'stall' in ice loss is probably an illusion with fragmented ice filling in open water so fooling the 15% or more measure into seeing ice gain where none is occurring?

My thoughts are " your old road is rapidly changing" and that things we once held as true may no longer necessarily be so? The rapidity of ice breakup and reduction in floe sizes must have some say in how fast that ice melts out under good melt conditions?
If we keep on with HP dominance across the basin we might witness a start to the season not seen since 2012 and the ice then , I believe, will have been more resilient to today's?

I doubt it is an illusion.  The extent maps show that while the Beaufort is mostly open, the rest of the Arctic is ice covered.  That would be a remarkable amount of fragmentation.  The more things change, the more they stay the same.
Title: Re: The 2018 melting season
Post by: gerontocrat on April 30, 2018, 06:38:17 PM
Extent and area loss as measured by NSIDC has been slow over the last few days. That is merely an observation - not a prediction.

Here is a prediction - warmth travelling north up the east coast of Greenland starting tomorrow to a maximum impact on Saturday will change things somewhat.
Title: Re: The 2018 melting season
Post by: gerontocrat on April 30, 2018, 10:38:45 PM
It also looks like temperatures at 80+ degrees North will be different from 2017 at least for the next few days
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 01, 2018, 12:41:26 AM
It also looks like temperatures at 80+ degrees North will be different from 2017 at least for the next few days

Something feels different about this year, but it is hard to find anything objective to make it clear... Just muttering about ice mobility, reminders of FDD...  For now we watch the Sunlight, and see if it spends a lot of time making it to the ground.
Title: Re: The 2018 melting season
Post by: litesong on May 01, 2018, 02:09:53 AM
The more things change, the more they stay the same.
It is good to hear that present Arctic sea ice maximums will return to 16+ million square kilometers & present Arctic sea ice will gain 8000+ cubic kilometers, back to 1980's levels........ NOT!!!
Title: Re: The 2018 melting season
Post by: litesong on May 01, 2018, 02:26:33 AM
.... we watch the Sunlight, and see if it spends a lot of time making it to the ground.
..... & that solar TSI is at sub-normal levels.
Title: Re: The 2018 melting season
Post by: Daniel B. on May 01, 2018, 02:45:47 AM
The more things change, the more they stay the same.
It is good to hear that present Arctic sea ice maximums will return to 16+ million square kilometers & present Arctic sea ice will gain 8000+ cubic kilometers, back to 1980's levels........ NOT!!!

Why would you think that?
Title: Re: The 2018 melting season
Post by: oren on May 01, 2018, 02:53:36 AM
I'll bring this here from the area/extent thread.
The crux being that April melt does not give any feel for the minimum?
The degradation of the ice across Beaufort, currently ongoing, will surely have impact on the rest of the melt season bringing a more mobile pack and areas of dark water to harvest any incoming solar?
The 'stall' in ice loss is probably an illusion with fragmented ice filling in open water so fooling the 15% or more measure into seeing ice gain where none is occurring?

My thoughts are " your old road is rapidly changing" and that things we once held as true may no longer necessarily be so? The rapidity of ice breakup and reduction in floe sizes must have some say in how fast that ice melts out under good melt conditions?
If we keep on with HP dominance across the basin we might witness a start to the season not seen since 2012 and the ice then , I believe, will have been more resilient to today's?
I think it's quite true that April extent does not give a feel for the minimum. Extent falls almost exclusively in the peripheral seas, some of them not even affecting the rest of the arctic, while the central basin even continues to thicken.
I do think this year might be somewhat different in terms of unpredictability, as it had a poor refreeze in a very specific area - Chukchi and Bering, and it had record early extent and area loss in the same region, plus it has lots of thin ice in the same region (see images). And this region does have implications for the rest of the arctic, both due to early advance of the melting front into the basin, and due to possible greater-than-usual warm Pacific water intrusion into the basin. But so much can happen from now to September that this is a weak effect.
Note that Beaufort had a worse start in 2016, and even 2015, so I'm not sure anything significant is happening there at the moment.
I also wish to note that while extent at maximum is very affected by the irrelevant Okhotsk, south Baffin, and other very peripheral locations, therefore subject to high variance, we still got the last three years become the lowest three years, hinting at some statistical change due to underlying physics.
Title: Re: The 2018 melting season
Post by: Alexander555 on May 01, 2018, 07:36:17 AM
It also looks like temperatures at 80+ degrees North will be different from 2017 at least for the next few days

Something feels different about this year, but it is hard to find anything objective to make it clear... Just muttering about ice mobility, reminders of FDD...  For now we watch the Sunlight, and see if it spends a lot of time making it to the ground.

I think we will see a very low september minimum. Very high anomolies at the Arctic ,almost the entire winter. And the cold that moved out was mainly over land. That has very little impact on the ice.
Title: Re: The 2018 melting season
Post by: jdallen on May 01, 2018, 08:26:59 AM
The more things change, the more they stay the same.
It is good to hear that present Arctic sea ice maximums will return to 16+ million square kilometers & present Arctic sea ice will gain 8000+ cubic kilometers, back to 1980's levels........ NOT!!!

Why would you think that?
Please don't bait people.    If you have a point to argue here (...the more they...), please offer your supporting facts.
Title: Re: The 2018 melting season
Post by: romett1 on May 01, 2018, 09:42:19 AM
Beaufort is moving fast as winds were favourable (Apr 28 - Apr 30). Also favourable winds expected for today. Images: Worldview and https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/arctic.html
Title: Re: The 2018 melting season
Post by: Alexander555 on May 01, 2018, 12:07:31 PM
And on top of a warm Arctic winter. We now already have small positive temperature anomaly in big area's not that far from the equator for many weeks .Like in places like India, Pakistan.... These anomalies are not big, but they come on top of already high temperaures. Probably they have been creating these high anomalies whe have seen in Europe and other places the last weeks. And that extra heat is now going to move into the Arctic, for at least a week. Creating positive temperatures in several area's in the arctic. That's at least one extra bad week for the Arctic ice. And that small positive anomaly near the equator is still going on. That gives the possibility for some extra bad weeks for the Arctic. There are several subjects i have to dig in deeper. Like snow cover and cloud cover, and these special events. Like these sudden stratosferic warming events. That probably all have a big impact. But because of that extra heat i think we are going to see a very low september minimum.
Title: Re: The 2018 melting season
Post by: Steven on May 01, 2018, 12:44:40 PM
Land snow cover extent for April 2018 was 1.84 million km2 above average.  It's similar to years like 2017 and 2013.

(https://i.imgur.com/0Qqz8us.png)

(https://i.imgur.com/akqXIOL.png)
https://climate.rutgers.edu/snowcover
Title: Re: The 2018 melting season
Post by: Daniel B. on May 01, 2018, 01:42:05 PM
2017 and 2013 where years which saw a significant increase in sea ice minimum over the preceding year.
Title: Re: The 2018 melting season
Post by: numerobis on May 01, 2018, 03:46:09 PM
2017 and 2013 where years which saw a significant increase in sea ice minimum over the preceding year.

1994 had a fair bit more ice than either 1995 or 1996, both of which had high snow cover anomalies. So your correlation doesn't check out well.

The northern hemisphere is very large compared to the Arctic. Most of the snow cover anomaly is in mid latitudes, under trees -- and is gone by early to mid May. I'm completely unconvinced there's any link at all with the ice.
Title: Re: The 2018 melting season
Post by: bbr2314 on May 01, 2018, 04:07:24 PM
2017 and 2013 where years which saw a significant increase in sea ice minimum over the preceding year.

1994 had a fair bit more ice than either 1995 or 1996, both of which had high snow cover anomalies. So your correlation doesn't check out well.

The northern hemisphere is very large compared to the Arctic. Most of the snow cover anomaly is in mid latitudes, under trees -- and is gone by early to mid May. I'm completely unconvinced there's any link at all with the ice.
Normally when there is extant snow cover trees don't have leaves, but maybe you don't live in a place where it snows?
Title: Re: The 2018 melting season
Post by: binntho on May 01, 2018, 04:09:55 PM
2017 and 2013 where years which saw a significant increase in sea ice minimum over the preceding year.

1994 had a fair bit more ice than either 1995 or 1996, both of which had high snow cover anomalies. So your correlation doesn't check out well.

The northern hemisphere is very large compared to the Arctic. Most of the snow cover anomaly is in mid latitudes, under trees -- and is gone by early to mid May. I'm completely unconvinced there's any link at all with the ice.
Normally when there is extant snow cover trees don't have leaves, but maybe you don't live in a place where it snows?
Well, pine and spruce never have leaves.
Title: Re: The 2018 melting season
Post by: bbr2314 on May 01, 2018, 04:11:32 PM
2017 and 2013 where years which saw a significant increase in sea ice minimum over the preceding year.

1994 had a fair bit more ice than either 1995 or 1996, both of which had high snow cover anomalies. So your correlation doesn't check out well.

The northern hemisphere is very large compared to the Arctic. Most of the snow cover anomaly is in mid latitudes, under trees -- and is gone by early to mid May. I'm completely unconvinced there's any link at all with the ice.
Normally when there is extant snow cover trees don't have leaves, but maybe you don't live in a place where it snows?
Well, pine and spruce never have leaves.

You can merely have an ass or you can actively be one.

(https://media.giphy.com/media/jUh1bllCt5oklIbcju/giphy.gif)

This notion that "trees mitigate snowcover" is literal horsesh*t. It is ignorance at best and dishonest at worst. If you want to talk about different kinds of leaves then the melting thread is not for you.
Title: Re: The 2018 melting season
Post by: gerontocrat on May 01, 2018, 04:13:42 PM
Is there historical data on snow on the treeless far north to the ocean edge of Canada and Russia? If snow persists there longer is it not there that an effect on the sea ice is more likely?
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 01, 2018, 04:26:51 PM
Normally when there is extant snow cover trees don't have leaves, but maybe you don't live in a place where it snows?

Normally, trees in areas that snow a lot are evergreens.
Title: Re: The 2018 melting season
Post by: binntho on May 01, 2018, 04:43:48 PM
Well, a quick look at the literature shows that snow over no-shrub tundra has the highest albedo, but also melts out much faster come spring. With increased vegetation, from dwarf shrub to low shrub to conifer forests, albedo drops significantly.In April (with snow cover), boreal forests have albedo of around 0.4, tree-shrub-mosaic tundra about 0.5, and other types of tundra between 0.72 and 0.76. Fresh snow has albedo of 0.8-0.9.

On longer timescales, since boreal forests and shrub cover is rapidly moving northwards, one would expect the effects of snow cover on albedo to drop as well.

Nowhere in the literature did I see any mention of asses or horses**t.
Title: Re: The 2018 melting season
Post by: litesong on May 01, 2018, 05:10:11 PM
Land snow cover extent for April 2018 was 1.84 million km2 above average.  It's similar to years like 2017 and 2013.

(https://i.imgur.com/0Qqz8us.png)

(https://i.imgur.com/akqXIOL.png)
https://climate.rutgers.edu/snowcover
Your North American charts are interesting. Comparing our small Washington state region is apples & oranges, but the 98-99 season at Mt. Baker, WA set the world snowfall record at 1140 inches. Previous to that, Mt. Rainier, WA had world snowfall record at 1122 inches. Half way between Baker & Rainier about 5-7(?) years ago, Skykomish, WA (in the mountains, but only 1200(?) foot elevation had snows that were 11 feet of snow in yards. Residents, while on their roofs trying to clear snows, had to pitch shovelfuls of snow.... upward to be able to clear the snows in their yards.   
Title: Re: The 2018 melting season
Post by: gerontocrat on May 01, 2018, 05:23:14 PM
This thread is getting snowed under  - again. There is a thread called - Northern hemisphere snow cover, there is a thread called - Land snow cover effect on sea ice.

I thought this thread was for the melting season.

But since you are all at it - I did a post today on the "Northern hemisphere snow cover" thread which included the following:-

Quote
Trends and Extremes in Northern Hemisphere Snow Characteristics
Abstract

Recent studies of snow climatology show a mix of trends but a preponderance of evidence suggest an overall tendency toward decreases in several metrics of snow extremes. The analysis performed herein on maximum seasonal snow depth points to a robust negative trend in this variable for the period of winter 1960/1961–winter 2014/2015. This conclusion is applicable to North America. Maximum snow depth is also mostly decreasing for those European stations analyzed. Research studies show generally negative trends in snow cover extent and snow water equivalent across both North America and Eurasia. These results are mostly, but not fully, consistent with simple hypotheses for the effects of global warming on snow characteristics.

ps: I want to see here all the really good stuff on what is physically happening to the ice in the Arctic.
Title: Re: The 2018 melting season
Post by: jdallen on May 01, 2018, 05:40:23 PM
This thread is getting snowed under  - again. There is a thread called - Northern hemisphere snow cover, there is a thread called - Land snow cover effect on sea ice.

<snip>
Shifting the discussion to there.

https://forum.arctic-sea-ice.net/index.php/topic,292.msg152440.html#msg152440
Title: Re: The 2018 melting season
Post by: RoxTheGeologist on May 01, 2018, 07:15:53 PM
This thread is getting snowed under  - again. There is a thread called - Northern hemisphere snow cover, there is a thread called - Land snow cover effect on sea ice.

<snip>
Shifting the discussion to there.

https://forum.arctic-sea-ice.net/index.php/topic,292.msg152440.html#msg152440

Good idea, as it looks like the North Pole might be getting a spot or two of rain by the end of the week.
Title: Re: The 2018 melting season
Post by: romett1 on May 01, 2018, 08:41:15 PM

Good idea, as it looks like the North Pole might be getting a spot or two of rain by the end of the week.


I agree - current models are showing that this heat is staying for quite a long time. And Morris Jesup weather station shows already 0 °C, that is jump from -19 °C. Image: http://www.dmi.dk/groenland/maalinger/vejret-lige-nu/stations/vis/4301
Title: Re: The 2018 melting season
Post by: oren on May 01, 2018, 10:49:54 PM
Thanks for the link Romett1. For some reason the whole "current weather" part does not exist in the English version of the DMI/Greenland website.
Title: Re: The 2018 melting season
Post by: FishOutofWater on May 02, 2018, 01:57:37 AM
In mid-February the NH had the most intense stratospheric warming on record as far as i know. The sudden stratospheric warming in mid January 2013 was very powerful. in 2017 the end warming went out with a huge pulse of heat to the upper stratosphere. Following these warmings momentum was transferred downwards causing the polar jet to expand southwards. All of these years had greater than average NH snow amounts and cool spring weather in the eastern U.S. and western Europe.

If you go back in the climate records you will find that strong stratospheric warmings are associated with the kind of weather we have seen since mid February. I'm not convinced, however, that this summer will be like summer 2013 because the effect of SSWs does not appear to last beyond one season.

Moreover, this year the north Atlantic overturning circulation in the Labrador sea appears to be much stronger than it was in 2013. Warm salty water has been pulled back up onto the the north side of the subpolar gyre in the Labrador sea, then cooled and mixed down to 2000m. Right now there's a burst of heat being released to the air above the far north Atlantic building an atmospheric ridge over norther Europe.

The net result is that the Arctic ice pack on the Atlantic side will be taking a hit over the next week.
Title: Re: The 2018 melting season
Post by: epiphyte on May 02, 2018, 03:31:51 AM
This thread is getting snowed under  - again. There is a thread called - Northern hemisphere snow cover, there is a thread called - Land snow cover effect on sea ice.

<snip>
Shifting the discussion to there.

https://forum.arctic-sea-ice.net/index.php/topic,292.msg152440.html#msg152440

Good idea, as it looks like the North Pole might be getting a spot or two of rain by the end of the week.

Rain? Rain, I ask you?
Please don't anyone say rain is off topic. That would (also) be very, very, silly.

PS. Got your fickle NH snow cover anomaly right here... My front lawn. April 15 vs May 01 2018
It's 2018. It's melting. It's the season for that.

ergo... It's on topic.
Title: Re: The 2018 melting season
Post by: JayW on May 02, 2018, 12:01:15 PM
102 hours loop April 27- May 1, Beaufort and some Chukchi.  Looks like most of the fast ice NE of Alaska has sheared away.  The Chukchi isn't freezing over anymore, at least the southern part, but low clouds ( likely due to the open water) are obscuring things.  The Beaufort is freezing over the leads opened up by the winds.

Contrast slightly increased for detail

http://feeder.gina.alaska.edu/npp-gina-alaska-truecolor-images?page=4&search%5Bfeeds%5D%5B5%5D=1&search%5Bsensors%5D%5B3%5D=1
Title: Re: The 2018 melting season
Post by: jdallen on May 02, 2018, 04:43:24 PM
I doubt the Beaufort leads will refreeze much past 10-20CM. That fragmentation is bad news.
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 02, 2018, 05:59:53 PM
As a gardener, I've always loved early spring snowfalls. The melting snow would seep into the ground and guarantee a healthy, early summer harvest.
Title: Re: The 2018 melting season
Post by: litesong on May 02, 2018, 06:05:36 PM
This thread is getting snowed under  - again.....I thought this thread was for the melting season.
The more snow that falls, means all the more snow that melts(never becoming hard ice?), under warming AGW conditions.  ;D
Title: Re: The 2018 melting season
Post by: Alexander555 on May 02, 2018, 07:53:53 PM
A little heat moving in.
Title: Re: The 2018 melting season
Post by: uniquorn on May 02, 2018, 08:02:02 PM
Ice lifting off the nth Greenland coast already.
Worldview terra/modis Apr30-May2
Title: Re: The 2018 melting season
Post by: uniquorn on May 02, 2018, 08:49:07 PM
Comparison with previous years on May2 2007-2018
Title: Re: The 2018 melting season
Post by: gerontocrat on May 02, 2018, 10:38:25 PM
The warmth heading up off the East Coast of Greenland is beginning to affect temperatures at 80+ North, and look to increase somewhat for a week or so. Warmer than 2017 by about 3 degrees at 2nd May.

Will the high Arctic be warmer than 2017? We are reaching the time of year when it matters.
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 02, 2018, 10:42:50 PM
The warmth heading up off the East Coast of Greenland is beginning to affect temperatures at 80+ North, and look to increase somewhat for a week or so. Warmer than 2017 by about 3 degrees at 2nd May.

Will the high Arctic be warmer than 2017? We are reaching the time of year when it matters.

Thanks for the vertical lines....they are so much better than my eyes -- and I was pretty sure I was seeing hotter than last year.
Title: Re: The 2018 melting season
Post by: gerontocrat on May 02, 2018, 10:54:35 PM


Thanks for the vertical lines....they are so much better than my eyes --

I am selfish - I did it for me but am glad others find it helpful. 
Title: Re: The 2018 melting season
Post by: litesong on May 03, 2018, 01:38:50 AM
Will the high Arctic be warmer than 2017? We are reaching the time of year when it matters.
When the sun is low on (or below) the High Arctic horizon, the everyday (fall, winter, & early spring?) weather of the High Arctic daily line gradually has been rising since 1958(before?), due to the increasing predominant AGW excess GHG heat(& positive feedbacks) building in Earth's biosphere. This effect has continued despite the Total Solar Irradiation decrease for the last 11+ years(including a 3+ year period with the TSI setting a 100 year record low). However, when the sun is not so low & high off the High Arctic horizon for as much as 24 hours per day, the TSI, low for the last 11+ years, is causing High Arctic summer temperatures to average slightly below the 1958-to-present average temperature.
It is remarkable that the "dark" season of the High Arctic is countering the low TSI. If the low TSI continues (or drops further) for decades(?), only the increasing strength of AGW GHG heat, can keep the High Arctic "dark" season from dropping.       
Title: Re: The 2018 melting season
Post by: Neven on May 03, 2018, 11:51:11 AM
On-topic, please.
Title: Re: The 2018 melting season
Post by: Neven on May 03, 2018, 12:38:08 PM
Here are the 925 hPa temperature graphs for April. Arctic overall was 5th lowest highest on record, Atlantic was 10th, Siberian was 15th, Pacific was lowest highest, Canadian was 23rd lowest highest on record:
Title: Re: The 2018 melting season
Post by: Neven on May 03, 2018, 12:52:53 PM
The current ECMWF weather forecast is very interesting as well. Aside from the heat coming in via the Atlantic, it seems that if the high pressure can't be over the CAB, it shifts on the periphery, looking for a way to get back in. In this case it forms a ridge of sorts from the Kara Sea to Alaska. It's May now. This should slowly start having an impact, even if imperceptible at first.
Title: Re: The 2018 melting season
Post by: slow wing on May 03, 2018, 12:57:08 PM
Here are the 925 hPa temperature graphs for April...
Very interesting, thanks Neven! How many years are on this record?
Title: Re: The 2018 melting season
Post by: Neven on May 03, 2018, 02:24:06 PM
Did you mean highest?

Yes, I did! Thanks, fixed now.

Quote
How many years are on this record?

1948-2018.
Title: Re: The 2018 melting season
Post by: Juan C. García on May 03, 2018, 03:14:16 PM
Here are the 925 hPa temperature graphs for April. Arctic overall was 5th lowest highest on record, Atlantic was 10th, Siberian was 15th, Pacific was lowest highest, Canadian was 23rd lowest highest on record:

From the first graph, I see it as the 4th highest...
Are there more years that we can analyzed?
Title: Re: The 2018 melting season
Post by: Neven on May 03, 2018, 05:19:01 PM
1995 was warmer as well, Arctic-wide (-9,354). I'll be more clear in the future that I'm referring to the 1948-2018 period, but that the graph only shows 2005-2018.
Title: Re: The 2018 melting season
Post by: uniquorn on May 03, 2018, 09:33:50 PM
Lift off from the north Greenland coast continues. The ice front retreats a little with the warmer wind.
Worldview terra/modis May1-3
Title: Re: The 2018 melting season
Post by: gerontocrat on May 03, 2018, 10:09:40 PM
It is getting warmer North of 80
Title: Re: The 2018 melting season
Post by: Juan C. García on May 03, 2018, 10:23:17 PM
It is getting warmer North of 80

Just to make the comment, I am not sure to put "Like" to something that I don't like!  :o
But thanks for the information!  ;)
Title: Re: The 2018 melting season
Post by: Neven on May 03, 2018, 10:50:39 PM
Even though 80N is only a small part of the Arctic, I still regard the DMI temperature graph as somewhat indicative of what's going on, a precursor of sorts. In this sense, the current high temperatures there may prove to be significant. Emphasis on 'may'.

Below is what I would consider the most important graph in the latest NSIDC summary (http://nsidc.org/arcticseaicenews/2018/05/arctic-winter-warms-up-to-a-low-summer-ice-season/). According to the summary there's a record high amount of FYI and record low amount of MYI:

Quote
As averaged over the Arctic Ocean (Figure 4d), the multiyear ice cover during week nine has declined from 61 percent in 1984 to 14 percent in 2018, the least amount of multiyear ice recorded. In addition, only 1 percent of the ice cover is five years or older, also the least amount recorded. This is rather striking since September 2017 did not set a new record low minimum extent. The proportion of first-year versus multiyear ice in spring will largely depend on the amount of open water left at the end of summer over which first-year ice forms. How much ice is transported out of the Arctic through Fram Strait in winter also plays a role. The unusually high amount of first-year ice this March suggests that there was a strong Fram Strait ice export this past winter. Given that (in the absence of ridging) first-year ice grows to about 1.5 to 2 meters (4.9 to 6.6 feet) thick over a winter season, the ice age data point to a fairly thin ice cover. Nevertheless, how much ice melts out this coming summer will depend strongly on summer weather conditions.

I'm not sure how accurate this is. For instance, I'm not seeing the band of MYI extending across the Beaufort towards Chukchi. A-Team, are you reading? What do you think?
Title: Re: The 2018 melting season
Post by: Neven on May 03, 2018, 10:54:52 PM
Here are ASCAT and AARI for around week 9:
Title: Re: The 2018 melting season
Post by: Neven on May 03, 2018, 11:02:29 PM
Wipneus also wrote in the PIOMAS thread recently:

Quote
PIOMAS has updated the so called gice data (upto 22th of April). As some will remember, ice in each gridcell in the PIOMAS model is specified as a discrete distribution: there exist 12 categories of ice thickness (m):
[0.00, 0.26, 0.71, 1.46, 2.61, 4.23, 6.39, 9.10, 12.39, 16.24, 20.62, 25.49]
gice specifies the percentage less or equal to the thickness of each category.

From these I calculate total area occupied for each cat as shown in the attached graph.

PIOMAS has the lowest area on the 22 April of all years, but more of that ice is thicker than in some recent years.

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=119.0;attach=100146;image)

For the time being, I'm not sure the ice age graph and map posted in the NSIDC summary are accurate, but don't have time to look into it more.
Title: Re: The 2018 melting season
Post by: be cause on May 04, 2018, 01:38:25 AM
So the dmi 80 has got back to where it was in late Feb ! This time it will keep on going . I don't believe I have seen such anomalously warm forecasts this time of year before , and if anything like them comes to pass then wreckords may litter this season ! b.c.
Title: Re: The 2018 melting season
Post by: GoSouthYoungins on May 04, 2018, 01:47:15 AM
Forecasts for May 6th and/or 7th look like the 80N mean temp will be a serious outlier for the 2nd time in less than 3 months.

The entire arctic seems to be similar to a barely refrozen slushy. And the Pacific and Atlantic ice edges are as close together as they have “ever” been this time of year.

The northern hemisphere’s temperature regulator appears near the precipice of a major shift. Every year in the next decade it becomes more likely to take the dive, at which time (if recent warming trends continue) it becomes inevitable irrespective of weather volatility.

With the temperature lid effectively removed, A) a drastically quicker atmospheric warming will commence, and B) immediate climate system chaos will occur.

First post. Howdy.
Title: Re: The 2018 melting season
Post by: Michael Hauber on May 04, 2018, 02:44:24 AM
(https://i.imgur.com/QoqfKZV.gif)

Circulation patterns for the last few months seem semi-favourable for multi-year ice retention.  The NSIDC doesn't just show a record low multi-year amount, but a very big record.  I doubt it is correct.

These circulation patterns would also help build up thicker ice in Siberian and Laptev regions (although temps would oppose this).
Title: Re: The 2018 melting season
Post by: Coffee Drinker on May 04, 2018, 03:27:55 AM
Major torch for southern Hudson Bay in extended forecast. Far out but 30C possible to destroy the ice.
http://www.wetterzentrale.de/en/topkarten.php?map=5&model=gfs&var=5&time=384&run=18&lid=OP&h=0&tr=3&mv=0
Title: Re: The 2018 melting season
Post by: jdallen on May 04, 2018, 05:55:47 AM
Even though 80N is only a small part of the Arctic, I still regard the DMI temperature graph as somewhat indicative of what's going on, a precursor of sorts. In this sense, the current high temperatures there may prove to be significant. Emphasis on 'may'.

Below is what I would consider the most important graph in the latest. According to the summary there's a record high amount of FYI and record low amount of MYI:
<snippage>
I'm in full consensus with you Neven.  The lack of MYI is a very big signal, and as most of that ice is under 2.5M in thickness, even a "normal" melt season could reach 2-3rd lowest extent/area/volume.

The table is set, weather is now key, and the high pressure and sunshine now hitting the Arctic from the Kara to Alaska may be very important, especially if it persists.
Title: Re: The 2018 melting season
Post by: bbr2314 on May 04, 2018, 06:26:25 AM
It looks like the impact of "no Fram" due to warmth will imminently entail the re-opening of Nares for export. Massive cracking extending towards it as of yesterday. Probably won't take much to break the arch and start early transport of MYI toward Baffin.

If model depiction of heat through D5 is correct, the transport may be more of an absolute gushing. That is... an enormous amount. The ATL front is going to be obliterated.

(https://www.tropicaltidbits.com/analysis/models/gfs/2018050400/gfs_T2ma_nhem_12.png)

(https://www.tropicaltidbits.com/analysis/models/gfs/2018050400/gfs_T2m_nhem_25.png)
Title: Re: The 2018 melting season
Post by: subgeometer on May 04, 2018, 01:15:12 PM
The 5 day anomaly forecast on GFS is pretty insane
Title: Re: The 2018 melting season
Post by: uniquorn on May 04, 2018, 02:33:12 PM
snippage
latest NSIDC summary..ice age wk9...I'm not sure how accurate this is. For instance, I'm not seeing the band of MYI extending across the Beaufort towards Chukchi.
3 clearish days from feb28-mar2 show the string of MYI floes fairly well using viirs band15. They appear to get progressively fractured and dispersed as they make their way round the Beaufort. (maybe even bottom melt in that area?)

worldview brightness temperature band15 night
https://tinyurl.com/y7wjshaz
Title: Re: The 2018 melting season
Post by: romett1 on May 04, 2018, 06:24:56 PM
It is getting warmer North of 80
As next 7 days are really interesting north of 80 °N, it is worth looking also FDD (Freezing Degree Days) anomaly. As March was colder than in 2016 and 2017, May seems to be a lot warmer (north of 80 °N). Since start of the year 2018 is now slightly warmer than 2017 (north of 80 °N) and is probably going to chase 2016 as well. Image: https://sites.google.com/site/cryospherecomputing/fdd
Title: Re: The 2018 melting season
Post by: romett1 on May 04, 2018, 07:22:23 PM
Also strong winds forecast for area north of Greenland, starting around Sunday and lasting until Wednesday. Captured this 115 km/h wind gust forecast for Tuesday morning (www.windy.com).
Title: Re: The 2018 melting season
Post by: diablobanquisa on May 04, 2018, 07:59:21 PM
Even though 80N is only a small part of the Arctic, I still regard the DMI temperature graph as somewhat indicative of what's going on, a precursor of sorts. In this sense, the current high temperatures there may prove to be significant. Emphasis on 'may'.

Below is what I would consider the most important graph in the latest NSIDC summary (http://nsidc.org/arcticseaicenews/2018/05/arctic-winter-warms-up-to-a-low-summer-ice-season/). According to the summary there's a record high amount of FYI and record low amount of MYI:

Quote
As averaged over the Arctic Ocean (Figure 4d), the multiyear ice cover during week nine has declined from 61 percent in 1984 to 14 percent in 2018, the least amount of multiyear ice recorded. In addition, only 1 percent of the ice cover is five years or older, also the least amount recorded. This is rather striking since September 2017 did not set a new record low minimum extent. The proportion of first-year versus multiyear ice in spring will largely depend on the amount of open water left at the end of summer over which first-year ice forms. How much ice is transported out of the Arctic through Fram Strait in winter also plays a role. The unusually high amount of first-year ice this March suggests that there was a strong Fram Strait ice export this past winter. Given that (in the absence of ridging) first-year ice grows to about 1.5 to 2 meters (4.9 to 6.6 feet) thick over a winter season, the ice age data point to a fairly thin ice cover. Nevertheless, how much ice melts out this coming summer will depend strongly on summer weather conditions.

I'm not sure how accurate this is. For instance, I'm not seeing the band of MYI extending across the Beaufort towards Chukchi. A-Team, are you reading? What do you think?

I'm afraid Tschudi et al. forgot the ice "birthday" on September 2017,  when 1st year ice (dark blue) becomes 2nd year ice (light blue) , light blue becomes green (3rd year ice), etc.

ftp://ccar.colorado.edu/pub/tschudi/iceage/data/

Look for instance at weeks 30, 38, 45:

ftp://ccar.colorado.edu/pub/tschudi/iceage/images/iceage_browse_week_n_2017_30_nrt.png
ftp://ccar.colorado.edu/pub/tschudi/iceage/images/iceage_browse_week_n_2017_38_nrt.png
ftp://ccar.colorado.edu/pub/tschudi/iceage/images/iceage_browse_week_n_2017_45_nrt.png


This could be affecting the results displayed at the time series on http://nsidc.org/arcticseaicenews/2018/05/

I've just sent a message to Mark Tschudi to let him know.




Title: Re: The 2018 melting season
Post by: Neven on May 04, 2018, 08:45:57 PM
I've just sent a message to Mark Tschudi to let him know.

I considered doing this also. Thanks a lot, Diablo.
Title: Re: The 2018 melting season
Post by: uniquorn on May 04, 2018, 09:28:52 PM
Cloudy north of Greenland today so I tried fitting together 2 of today's Sentinel1 SAR images on polarview. The result is not that helpful, but it is possible to see the refreeze of the March storm broken by the current lift off due to warmer southerlies.

https://www.polarview.aq/arctic
Title: Re: The 2018 melting season
Post by: diablobanquisa on May 04, 2018, 10:08:40 PM
I've just sent a message to Mark Tschudi to let him know.

I considered doing this also. Thanks a lot, Diablo.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F4786%2Ferror_wjt0.PNG&hash=ed9a58472fcdcdd00c5fb173006bf676)

 ;)

Title: Re: The 2018 melting season
Post by: Neven on May 04, 2018, 10:58:11 PM
A quick FYI (for your information, not first-year ice, you dummy  ;) ): I have updated the Concentration Maps pages (https://sites.google.com/site/arcticseaicegraphs/concentration-maps) on the ASIG all the way to November, so you can compare the current situation to previous years at any point during this melting season.
Title: Re: The 2018 melting season
Post by: Neven on May 04, 2018, 11:20:21 PM
ECMWF forecast (https://www.tropicaltidbits.com/analysis/models/?model=ecmwf&region=nhem&pkg=z500_mslp&runtime=2018050412&fh=144) remains highly interesting, with high pressure picketing on the Siberian side, trying to get to the Beaufort, but not quite making it. The Sun is getting higher, those Siberian seas are at lower latitudes, this should start to have an impact in the form of the first early melt ponds. Especially with that heat pulse washing over in the next couple of days.

Not much export through Fram Strait, which might help the trend line on the Barentsz Sea regional SIA graph to finally start going down.
Title: Re: The 2018 melting season
Post by: subgeometer on May 05, 2018, 01:06:42 AM
The ice edge around Svalbard will see a lot of wave action over the next few days. The series of lows passing over also bring rain to the ice to the south and east in the Barents, and maybe further north, The winds will be pushing the ice back as well so extent and area should start going down there

https://www.windy.com/?waves,76.660,-0.791,3,i:pressure,m:fY5afD5
Title: Re: The 2018 melting season
Post by: romett1 on May 05, 2018, 10:07:37 AM
As next 7 days are anyway interesting north of 80 °N, it is worth looking also longer term forecast. Current models are forecasting new heatwave from the Atlantic side between May 11 and May 16. Image for May 14: https://www.tropicaltidbits.com/analysis/models/
Title: Re: The 2018 melting season
Post by: uniquorn on May 05, 2018, 10:14:19 AM
Ascat apr26-may4

imagej brightness/contrast 37,255 clahe 63,256,2.2
Title: Re: The 2018 melting season
Post by: johnm33 on May 05, 2018, 11:15:41 AM
I'm reading this as the weak ice unable to resist deep wave action
(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/beaufortstrength_nowcast_anim30d.gif)
The other models are worth a look https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/beaufort.html
Title: Re: The 2018 melting season
Post by: wili on May 05, 2018, 12:46:28 PM
(Not sure where to put this, and apologies if it's already been posted somewhere)

Growing Land‐Sea Temperature Contrast and the Intensification of Arctic Cyclones

"By comparing statistics for years with high land‐sea thermal contrast against years with low, we demonstrate that storms over the Arctic Ocean will likely become more frequent and more dynamically intense as the climate warms, increasing the risk to shipping and other human activities."

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL077587

Sooo, probably more and stronger 'GAC's coming soon to an Arctic near you!  :) :-\
Title: Re: The 2018 melting season
Post by: Alexander555 on May 05, 2018, 01:05:07 PM
Is there an update for this one, or an easy way to check it ?
Title: Re: The 2018 melting season
Post by: uniquorn on May 05, 2018, 01:39:36 PM
http://ocean.dmi.dk/arctic/meant80n.uk.php
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 05, 2018, 01:42:33 PM
http://ocean.dmi.dk/arctic/meant80n.uk.php

It's also on the Arctic Sea Ice page

https://sites.google.com/site/arcticseaicegraphs/
Title: Re: The 2018 melting season
Post by: gerontocrat on May 05, 2018, 02:12:43 PM
Is there an update for this one, or an easy way to check it ?

The comparison with 2017 on the graph is constructed by yours truly when he is in the mood.
Title: Re: The 2018 melting season
Post by: Aluminium on May 05, 2018, 03:10:43 PM
Is there an update for this one, or an easy way to check it ?
It isn't difficult to make it. There are no significant changes compared to the last (https://forum.arctic-sea-ice.net/index.php/topic,2278.msg152800.html#msg152800).
Title: Re: The 2018 melting season
Post by: Tor Bejnar on May 05, 2018, 03:42:53 PM
Has anyone made a graph comparing the current year DMI 80N with the historical daily max?  Just thumbing through the years works some, but the graphs' structure changed some in 2006-2011 period.  2009 & 10 appear to have warmer 80N readings around today's date.  (I note that DMI's 80N calculation is strongly north-pole biased and that there could be a better metric used to discern central Arctic (or the slightly different Central Arctic Basin - CAB) air-temperature related vulnerability.)
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 05, 2018, 03:52:01 PM
Has anyone made a graph comparing the current year DMI 80N with the historical daily max?

Somone basically recolored all the years and overlaid them on the same graph so it was fairly easy to see how the current year compared to the past, but I don't know where to find it or if it is updated.  I think it was done by one of the posters here.
Title: Re: The 2018 melting season
Post by: S.Pansa on May 05, 2018, 04:08:23 PM
Has anyone made a graph comparing the current year DMI 80N with the historical daily max?

Somone basically recolored all the years and overlaid them on the same graph so it was fairly easy to see how the current year compared to the past, but I don't know where to find it or if it is updated.  I think it was done by one of the posters here.

Perphaps it is this graph from Zachary Labe? More graphs are available  here (http://sites.uci.edu/zlabe/arctic-temperatures/)
Title: Re: The 2018 melting season
Post by: dnem on May 05, 2018, 04:24:25 PM
Looks like the 2009 peak was a few days later, and warmer, than the current one.
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 05, 2018, 04:31:46 PM
Perphaps it is this graph from Zachary Labe? More graphs are available  here (http://sites.uci.edu/zlabe/arctic-temperatures/)

Yes, and the other graphs are good too.
Title: Re: The 2018 melting season
Post by: Tor Bejnar on May 05, 2018, 05:45:08 PM
Ta, y'all. (to mix a metaphor)
Title: Re: The 2018 melting season
Post by: be cause on May 05, 2018, 06:06:22 PM
regarding the dmi 80 .. this does not look like a spike .. rather we have arrived where we are 17 days earlier than last year .. and the heat seems to want to hang around . 17 days added to the melt season at this stage could easily equate to 1 to 2 million sq kms of extra ice loss ... b.c.
Title: Re: The 2018 melting season
Post by: gerontocrat on May 05, 2018, 06:21:49 PM
Is there an update for this one, or an easy way to check it ?
It isn't difficult to make it. There are no significant changes compared to the last (https://forum.arctic-sea-ice.net/index.php/topic,2278.msg152800.html#msg152800).
Difficult? No.
A bit fiddly? Yes.

So I can look forward to being lazy and watching your updates. (The sun is shining in Middle England)

ps:Zlabe's graph is a bit behind the curve. Temperatures North of 80 are now a bit above -10 celsius. They tell me that this means Arctic Sea Ice there is in a new environment - resistance to further ice thickening.
Title: Re: The 2018 melting season
Post by: gerontocrat on May 05, 2018, 11:21:29 PM
Can't resist an update. Temp North of 80 on 5 May just 6 degrees below zero. Sea ice freezing point minus 1.8 degrees celsius. Probably more upward movement Sunday 6 May and Monday 7 May.

But GFS has changed its mind about a super warming after Monday - now saying by next Wednesday much more modest temperature anomalies (but another big Atlantic side warming starting Sunday May 13?)
Title: Re: The 2018 melting season
Post by: Tor Bejnar on May 05, 2018, 11:28:47 PM
"Temp North of 80 on 5 May just 6 degrees below zero."
From what I've learned on these threads: if the 2 meter air temperature is -6C and it has been colder (in recent weeks), the surface ice will be a little below -6 and deeper ice will be colder still, then warming up to about -2 at the ice/water interface when ice growth happens.  How long will it take for the colder 'middle ice' to warm up (due to water freezing below and air (and sunlight) warming it from above? Historically, I think, it was late May or earliest June when the CAB stopped gaining volume.  Will this transition happen earlier this year?
Title: Re: The 2018 melting season
Post by: uniquorn on May 05, 2018, 11:36:05 PM
Yesterdays DMI ice surface temperature.
edit-image was very black
Title: Re: The 2018 melting season
Post by: Neven on May 05, 2018, 11:51:04 PM
Given the current ECMWF weather forecast (reinforcing the one I posted yesterday, in the sense that everything has moved one day closer without changing all that much) and the state of the ice in the Barentsz Sea according to SMOS, there should be some big regional drops there in the coming week, especially if that 984 hPa cyclone comes about 5 days from now. 1030 hPa over the Beaufort/Chukchi isn't to be sneezed at either.
Title: Re: The 2018 melting season
Post by: uniquorn on May 05, 2018, 11:55:26 PM
Good visibility on Worldview over much of the arctic for the last month gives an opportunity to look at the ice above the Chukchi Plateau. Apr7-May5
Title: Re: The 2018 melting season
Post by: S.Pansa on May 06, 2018, 07:14:44 AM
In regard to the points Neven has made above, the experimental NOAA ESRL page - introduced by A-Team if I remember correctly, who else - has some really nice illustrations and animations. Below the 5-day-forecasts for sea ice thickness & thickness change.

Plus a snapschot of the temp and SLP forecast for +144h.

It is taken from this animation (https://www.esrl.noaa.gov/psd/forecasts/seaice/) [edit: Oh well - direct linkt doesn't work. The said animation is called "2m Temp, SLP, 10m Winds", to be found in the Atmosphere-section], where we can see how the aforesaid high pressure dome is trying to establish itself all the way from Banks Island to Severnaya Zemlya.
Title: Re: The 2018 melting season
Post by: jdallen on May 06, 2018, 07:39:40 AM
Can't resist an update. Temp North of 80 on 5 May just 6 degrees below zero. Sea ice freezing point minus 1.8 degrees celsius. Probably more upward movement Sunday 6 May and Monday 7 May.

But GFS has changed its mind about a super warming after Monday - now saying by next Wednesday much more modest temperature anomalies (but another big Atlantic side warming starting Sunday May 13?)
We have passed the temperature at which open leads can easily refreeze. (~ -10C/263K)
Title: Re: The 2018 melting season
Post by: Dryland on May 06, 2018, 04:13:28 PM
In regard to the points Neven has made above, the experimental NOAA ESRL page - introduced by A-Team if I remember correctly, who else - has some really nice illustrations and animations.

I have some of these ESRL products organized for easy access at https://floe.keytwist.net (https://floe.keytwist.net), under Collections/Daily ESRL Forecasts.
Title: Re: The 2018 melting season
Post by: Vergent on May 06, 2018, 06:13:30 PM
(https://i.imgur.com/sWaxsll.png)

The high arctic thaw has begun!

(https://i.imgur.com/Q0UUo1P.png)

The 80N temperature spike is unprecedented...At least since 2000. At this time of year it is usually hugging the mean line.


Verg
Title: Re: The 2018 melting season
Post by: FishOutofWater on May 06, 2018, 06:33:54 PM
This amount of heat at the pole in early May is unprecedented, period. I looked back to 1958. There was a pretty good spike in 2006 but there's nothing as warm as this so early.
Title: Re: The 2018 melting season
Post by: litesong on May 06, 2018, 07:03:21 PM
(https://i.imgur.com/Q0UUo1P.png)
The 80N temperature spike is unprecedented...At least since 2000. At this time of year it is usually hugging the mean line.
Looks like the fairly large over-temperature hot spot, sitting on the North Pole, might continue sitting there for the next 5 days (even to 10 days?). Smaller cyclonic weather systems may nibble at edges of the hot spot.
Title: Re: The 2018 melting season
Post by: Vergent on May 06, 2018, 08:19:29 PM
GFS is predicting a huge Pacific side snow melt over the next 10 days.

(https://i.imgur.com/c0yeowK.png)

(https://i.imgur.com/uVmKyxX.png)

Verg
Title: Re: The 2018 melting season
Post by: magnamentis on May 06, 2018, 08:26:14 PM
thanks for the info but what is crossing my mind, is it that hard to predict huge snow melt in may once a lot of snow is around by then?

sorry if i sound negative but something with this kind of news (in general) triggers something inside me, probably because the world of news is so overloaded with meaningless headlines and content that does often not even reflect the headlines.

perhaps i'm wrong with this but still, it's what i thought while i was reading that.
Title: Re: The 2018 melting season
Post by: magnamentis on May 06, 2018, 08:33:02 PM
i think it's basically even somehow luck that it happens so early because if this spike would happen in about 2-4 weeks it would most probably have a catastrophic impact on the reminder of the ice that's mostly first year ice nowadays. if temps will settle to something more close to normal in about 2-3 weeks we could just have dodged the cannon ball for another year.

EDIT: of course, if this pattern is going to more or less last for another 2-3 weeks that was probably it, whatever it means, trying to avoid mistakes of the past here LOL

EDIT-2:  the link for uni-bemen maps has changed so that the link in the ASIG page is mute for now, below you find the currently working link to bookmark until ASIG will be updated:

https://seaice.uni-bremen.de/sea-ice-concentration/
Title: Re: The 2018 melting season
Post by: Koop in VA on May 06, 2018, 08:55:29 PM
I, for one, am glad that the snow depth forecast graphic was posted and, if Vargent hadn't done it, I was going to do it myself.  While Vargent points out the large Pacific snow melt out what struck me was that Scandinavia was modeled to be snow free in 10 days and that the land areas around Kara that have 3 to 4 feet of snow was going to see significant melt as well.  Finally, on the Kara Sea itself there was going to be significant snow melt as well that would likely cause the infamous melt ponds.

But to magnamentis' point, I don't have enough context on this melt.  Yes, it's May and it should be expected to have the snow melt.  But the degree of melt within the next 10 days seems rather large but is there enough institutional knowledge here to understand if this is well beyond standard melt?

Further, if it is a large melt, what does a significant in rush of 33 degree F water do to the melt of sea ice in the Kara or the Laptev?  More questions than answers but to see Alaska, except the North Slope, be predicted to be essentially snow free and to see the same in Scandinavia by mid-May seems like a fairly big deal.  But is there a website that can put this melt in context?
Title: Re: The 2018 melting season
Post by: litesong on May 06, 2018, 09:58:27 PM
....what is crossing my mind, is it that hard to predict huge snow melt in may once a lot of snow is around by then? .....sorry if i sound negative.....
Actually, you sound like you believe in AGW. Tho AGW scientists predict increases in precipitation(snow, fer sure), it is also construed that global AGW excess heat will not let extra snow become extra long term snow to necessarily become excess ice. 
Title: Re: The 2018 melting season
Post by: Steven on May 06, 2018, 10:51:54 PM
GFS is predicting a huge Pacific side snow melt over the next 10 days.

GFS is not reliable for snow depth on Arctic sea ice.  Every year, the model exaggerates the speed at which the snow melts.  See for example the GFS snow depth forecasts that were posted on this forum in the past few years, e.g. the forecasts for 20 May 2017 (https://i.imgur.com/BloVmGH.jpg) and for 18 May 2016 (https://i.imgur.com/PxgqsZ1.png).  Neither of those forecasts was successful.
Title: Re: The 2018 melting season
Post by: magnamentis on May 07, 2018, 12:00:27 AM
....what is crossing my mind, is it that hard to predict huge snow melt in may once a lot of snow is around by then? .....sorry if i sound negative.....
Actually, you sound like you believe in AGW. Tho AGW scientists predict increases in precipitation(snow, fer sure), it is also construed that global AGW excess heat will not let extra snow become extra long term snow to necessarily become excess ice.

all that is 100% true, i just can't see where i said otherwise but however, yes, that's how i see things ;)
Title: Re: The 2018 melting season
Post by: jdallen on May 07, 2018, 07:14:34 AM
GFS is predicting a huge Pacific side snow melt over the next 10 days.

Verg

If I recall correctly from looking at various weather models, I believe the Chukchi is going to get some rain, which might explain the rapid drop.
Title: Re: The 2018 melting season
Post by: uniquorn on May 07, 2018, 10:30:25 AM
Sea ice dragon.
Polarview Sentinel 1 SAR north of Svalbard
Title: Re: The 2018 melting season
Post by: dosibl on May 07, 2018, 04:19:36 PM
Is there a product or model people would recommend for tracking cloud cover? CCI reanalyzer has a precipitation/cloud cover display but its hard to judge clouds on ice.
Title: Re: The 2018 melting season
Post by: Neven on May 07, 2018, 09:39:39 PM
Zack Labe has updated his DMI 80N temp graph. This year clearly standing out. Thanks, Zack!
Title: Re: The 2018 melting season
Post by: bbr2314 on May 07, 2018, 09:47:43 PM
Zack Labe has updated his DMI 80N temp graph. This year clearly standing out. Thanks, Zack!
It is interesting to look at how the graphs had compared with previous years as the same "head and shoulders" leads were a good benchmark for the ensuing anomalies in autumn. I would think this portends a very, very warm fall for the Atlantic-facing regions of the Arctic.
Title: Re: The 2018 melting season
Post by: uniquorn on May 07, 2018, 10:32:08 PM
Anomalously thick ice in the Laptev Sea, May4

Worldview terra/modis, viirs brightness temperature band 15, night
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 08, 2018, 01:34:55 AM
Anomalously thick ice in the Laptev Sea, May4

How do you determine the thickness of the ice from the images?
Title: Re: The 2018 melting season
Post by: subgeometer on May 08, 2018, 01:45:32 AM
This amount of heat at the pole in early May is unprecedented, period. I looked back to 1958. There was a pretty good spike in 2006 but there's nothing as warm as this so early.

The DMI chart is calculated from ECMWF which currently  at initialisation/000 hrs shows temps just below freezing over the pack north of Svalbard to the pole and beyond, rather than just above as per GFS. Unprecedented warmth either way.

I think it's safe to say that the Svalbard bite won't close before summer, as ATeam predicted. It looks to have become a permanent feature. The past few days the ice edge hasbeen pushed back almost 50km, and melt is evident at its edge. Looking through Bremen thin ice charts, their has been a 50km wide band of thin ice at the pack edge nort of Svalbard going back as far as I looked(feb), testament to the energy available there for melt. And it will be open for the 3 next months of serious insolation, so it will be interesting to see how warm the water gets
Title: Re: The 2018 melting season
Post by: subgeometer on May 08, 2018, 02:15:31 AM
I, for one, am glad that the snow depth forecast graphic was posted and, if Vargent hadn't done it, I was going to do it myself.  While Vargent points out the large Pacific snow melt out what struck me was that Scandinavia was modeled to be snow free in 10 days and that the land areas around Kara that have 3 to 4 feet of snow was going to see significant melt as well.  Finally, on the Kara Sea itself there was going to be significant snow melt as well that would likely cause the infamous melt ponds.

But to magnamentis' point, I don't have enough context on this melt.  Yes, it's May and it should be expected to have the snow melt.  But the degree of melt within the next 10 days seems rather large but is there enough institutional knowledge here to understand if this is well beyond standard melt?

Further, if it is a large melt, what does a significant in rush of 33 degree F water do to the melt of sea ice in the Kara or the Laptev?  More questions than answers but to see Alaska, except the North Slope, be predicted to be essentially snow free and to see the same in Scandinavia by mid-May seems like a fairly big deal.  But is there a website that can put this melt in context?

GFS is generally way too aggressive in its snow melt predictions.
Title: Re: The 2018 melting season
Post by: jdallen on May 08, 2018, 02:16:22 AM
Anomalously thick ice in the Laptev Sea, May4

How do you determine the thickness of the ice from the images?
I think uniquorn's comment was somewhat tongue-in-cheek, considering how fractured the ice appears.

If it is anomalously thick, it's not by much, and not sufficient to protect the ice from forces which attack it structurally.
Title: Re: The 2018 melting season
Post by: slow wing on May 08, 2018, 02:31:57 AM
Clouds or melt ponds?

Looking at Worldview visible, North of Svalbard (details in image names) & the ice looks qualitatively different than it was previously.

It could just be cloud formations but, if so, these would have to be strange given what I would describe as a 'grooves & angles' appearance.

It was above freezing in the region displayed, around approximately 83.63N, 4.17E, on 2018-05-06 at 1200 UTC. (It's colder there now, ~-10 degrees C.)

So could the Worldview experts comment on whether large scale melt ponds could be an alternative possible explanation, even early in May?
Title: Re: The 2018 melting season
Post by: oren on May 08, 2018, 02:44:38 AM
At this time I would say artifact/cloud, due to the sudden appearance over a largish area, lack of bluish tinge, and seeming lack of correlation to floe delineations. But another day or two could flip the verdict.
Title: Re: The 2018 melting season
Post by: FishOutofWater on May 08, 2018, 03:31:55 AM
Anomalously thick ice in the Laptev Sea, May4

How do you determine the thickness of the ice from the images?

By going to the PIOMAS thread.
Title: Re: The 2018 melting season
Post by: slow wing on May 08, 2018, 04:22:20 AM
Thanks Oren, yes I took a closer look and agree it's probably strange clouds rather than melt ponds.

It was too cloudy on the day before, 2018-05-06, for all three satellites, and mostly too cloudy for the other satellites on the same day, 2018-05-07. (Already suggesting a lot of cloud about.)

But I was able to scan around the TERRA view and see a progression to other structures that tended to look more cloud-like.

Also, there was a small gap in the AQUA cloud cover showing white ice in the same identifiable ice position where the TERRA view showed those structures - at around 81.81N, 5.44E - compare the attached images.

So yes, the structure seems to be cloud &/or artifacts rather than melt ponds.
Title: Re: The 2018 melting season
Post by: uniquorn on May 08, 2018, 10:21:53 AM
Anomalously thick ice in the Laptev Sea, May4

How do you determine the thickness of the ice from the images?
I think uniquorn's comment was somewhat tongue-in-cheek, considering how fractured the ice appears.

If it is anomalously thick, it's not by much, and not sufficient to protect the ice from forces which attack it structurally.

Sorry. I should have referenced the PIOMAS and Cryosat anomalies.
https://forum.arctic-sea-ice.net/index.php/topic,119.msg153178.html#msg153178
Title: Re: The 2018 melting season
Post by: JayW on May 08, 2018, 12:25:18 PM
Looking at the tightly packed isobars, there should be some strong easterly winds over the Beaufort beginning in a couple days, if the ECMWF is to be believed.  Unlike last week, the winds are progged to be warmer, so I wouldn't expect the leads to freeze over this time.  While there appears to be some thicker multi year ice in the Beaufort Sea, there is also a fair amount of ice that is only weeks old that formed in leads opened by previous wind events. Could be an interesting week.

https://www.tropicaltidbits.com/analysis/models/?model=ecmwf&region=ak&pkg=z500_mslp&runtime=2018050800&fh=72
Title: Re: The 2018 melting season
Post by: Neven on May 08, 2018, 12:27:48 PM
The NSIDC has posted the correct ice age figure:
Title: Re: The 2018 melting season
Post by: Neven on May 08, 2018, 12:46:20 PM
Looking at the tightly packed isobars, there should be some strong easterly winds over the Beaufort beginning in a couple days, if the ECMWF is to be believed.  Unlike last week, the winds are progged to be warmer, so I wouldn't expect the leads to freeze over this time.  While there appears to be some thicker multi year ice in the Beaufort Sea, there is also a fair amount of ice that is only weeks old that formed in leads opened by previous wind events. Could be an interesting week.

Indeed, Jay, the ECMWF SLP forecast for the coming six day, is a serious affair (especially combined with the anomalous heat). 1025-1035 hPa, all over the Central Arctic. This kind of weather in June or July would be a disaster for the ice, but it's not so great now either. Beaufort Gyre, here we come.
Title: Re: The 2018 melting season
Post by: VeliAlbertKallio on May 08, 2018, 12:50:38 PM
Already back in 1950's Maurice Ewing and William Donn of Columbia University's then Lamont Geological Observatory, Palisades, New York extrapolated from the Great Lakes area lake-snow effect a similar effect for the Arctic Ocean. They proposed that global warming (aka: entry to the Interglacial) would first drive the Arctic Ocean to melt and loose its ice cover. Then the dark and exposed Polar water surface would build up so much heat in the summer that the resulting snowfall during the winter would become so big that it just could not melt away. This then tips the system (due to albedo change) to a cooling regime and the onset of the next Ice Age. This explanation for the ice ages failed due to sediment cores on the ocean beds not supporting it. Recently it has become blatantly obvious that if ocean warms, the permafrost also warms leading to high microbial activity beneath fallen snow cover, absorbtion of heat by deep soil layers that form pingos that then collapse as methane craters. In addition to albedo the rising methane, carbon dioxide, nitrous oxide, and water vapour - all conspire against the Ewing-Donn Lake Snow Effect from the Arctic Ocean with more snowfall becoming a runaway effect (a tight feedback loop). It doesn't. This brought Milutin Milanković back from the graveyard of abandoned theories. Thus, despite we see an intensifying Ewing-Donn Lake Snow Effect from the Arctic Ocean with more snowfall it will not lead to any substantial negative feedback in snowmelt. Obviously, thicker snow can take longer if weather conspires by cold temperatures and/or shielding cloud cover (a respondent negative feedback effect). 2018 looks bad already.

....what is crossing my mind, is it that hard to predict huge snow melt in may once a lot of snow is around by then? .....sorry if i sound negative.....
Actually, you sound like you believe in AGW. Tho AGW scientists predict increases in precipitation(snow, fer sure), it is also construed that global AGW excess heat will not let extra snow become extra long term snow to necessarily become excess ice.
Title: Re: The 2018 melting season
Post by: numerobis on May 08, 2018, 05:00:48 PM
It was a warm April but so far a cold May on Frobisher Bay.

Rumour is the ice is worse than usual near the floe edge. It's still solid as far as you can see from town, no melt ponds yet (if there were, it would be crazy early), but satellite photos of the polynya looks bigger than usual.
Title: Re: The 2018 melting season
Post by: jdallen on May 08, 2018, 06:53:10 PM
Looking at the tightly packed isobars, there should be some strong easterly winds over the Beaufort beginning in a couple days, if the ECMWF is to be believed.  Unlike last week, the winds are progged to be warmer, so I wouldn't expect the leads to freeze over this time.  While there appears to be some thicker multi year ice in the Beaufort Sea, there is also a fair amount of ice that is only weeks old that formed in leads opened by previous wind events. Could be an interesting week.

Indeed, Jay, the ECMWF SLP forecast for the coming six day, is a serious affair (especially combined with the anomalous heat). 1025-1035 hPa, all over the Central Arctic. This kind of weather in June or July would be a disaster for the ice, but it's not so great now either. Beaufort Gyre, here we come.
We should see significant lift off from the Alaskan coast and significant increases in open water in the Chukchi.
Title: Re: The 2018 melting season
Post by: romett1 on May 08, 2018, 07:44:53 PM
Small update about FDD (Freezing Degree Days) anomaly north of 80 °N. Not surprisingly May has been warm (north of 80 °N) and still trying to chase 2016 as well (since start of the year). Image: https://sites.google.com/site/cryospherecomputing/fdd
Title: Re: The 2018 melting season
Post by: FishOutofWater on May 08, 2018, 09:26:12 PM
If there's a worse NH atmospheric circulation pattern than this European model ensemble forecast for Arctic sea ice, I don't know what it is, and I certainly don't want to see it.

This is the worst time of the year for excess Arctic heat because the decreased albedo will enhance melting through the whole melt season.
Title: Re: The 2018 melting season
Post by: jdallen on May 08, 2018, 10:14:54 PM
If there's a worse NH atmospheric circulation pattern than this European model ensemble forecast for Arctic sea ice, I don't know what it is, and I certainly don't want to see it.

This is the worst time of the year for excess Arctic heat because the decreased albedo will enhance melting through the whole melt season.

That forecast is a long way out (May 18), but even if not accurate, does suggest the trend.

I agree, if this plays out it suggests serious trouble.
Title: Re: The 2018 melting season
Post by: numerobis on May 08, 2018, 11:11:54 PM
Nice big blue spot over my head on that map ;)
Title: Re: The 2018 melting season
Post by: uniquorn on May 08, 2018, 11:18:59 PM
It looks like we just started exporting MYI on the Pacific side.
Ascat mar21-may7

imagej brightness/contrast 43,255 (some loss), CLAHE 63,256,2.2
2 frames deleted due to very poor data, some parts grey filled to reduce distraction
Title: Re: The 2018 melting season
Post by: uniquorn on May 09, 2018, 12:07:13 AM
I tried to confirm this using Worldview but I could only find a couple of floes. Taking a wider view in the second animation, thicker ice often shows brighter on VIIRS band15 when the weather is clear.
I think the forecast is for winds in the same direction. Will have to watch for a few days.
Title: Re: The 2018 melting season
Post by: Telihod on May 09, 2018, 11:17:42 AM
10 day forecast. (Max temperature.)

Title: Re: The 2018 melting season
Post by: El Cid on May 09, 2018, 01:48:13 PM
10 day forecast. (Max temperature.)

Maybe (IMO) even more important than temperature is that huge high pressure zone, right where it shouln't be: the attack is coming from the already weakened Pacific side and could gain traction very fast.
Title: Re: The 2018 melting season
Post by: uniquorn on May 09, 2018, 02:44:19 PM
Beaufort MYI string export on ascat apr22-may8
Worldview may8. Significant refreeze on previously open water, or is it snow? There has been a lot of cloud there over the last few days.

The ascat animation is significantly enhanced.
imagej: brightness/contrast 41,255 CLAHE 63,256,2.2 scale x2. unsharp mask 1,0.6
Title: Re: The 2018 melting season
Post by: numerobis on May 09, 2018, 07:23:18 PM
10 day forecast. (Max temperature.)

Personally I'd be happier if we kept this thread closer to the observations. I can wait ten days to see what happened, whereas looking forward ten days from now is a total crapshoot (especially with GFS).
Title: Re: The 2018 melting season
Post by: gerontocrat on May 09, 2018, 08:04:44 PM
10 day forecast. (Max temperature.)

Personally I'd be happier if we kept this thread closer to the observations. I can wait ten days to see what happened, whereas looking forward ten days from now is a total crapshoot (especially with GFS).

Is GFS totally at fault ? I've just scrolled through cci-reanalyzer using the hourly forecast slider and I have seen nothing to match the image posted by Telihod. It all looked very ordinary to me - warmth and cold moving anti-clockwise around and no massive anomalies.
Title: Re: The 2018 melting season
Post by: Greenbelt on May 09, 2018, 08:25:37 PM
The operational GFS and ECMWF seem in quite good agreement on a big surface high pressure over the central arctic around 1030mb over at least the next five days.  While the 10-day projections might be fanciful, the 5-7day outlooks have tended to be decent on broad features when there's model consensus, at least at lower latitudes, and I suspect the predictions are improving up north too. Will be interesting to see if we can spot melt pond formation signals after this big high (presumably) sets up, or if that's still too early season for that at the highest latitudes.
(https://www.tropicaltidbits.com/analysis/models/ecmwf/2018050912/ecmwf_z500_mslp_nhem_6.png)
(https://www.tropicaltidbits.com/analysis/models/gfs/2018050912/gfs_z500_mslp_nhem_21.png)
Title: Re: The 2018 melting season
Post by: numerobis on May 09, 2018, 09:04:49 PM
gerontocrat: weather forecasting is hard. I don't exactly blame GFS. They've not kept up with the quality that ECMWF manages, but both are pretty random at 10 days out. Both are much better at 5 days and in most places excellent at 2 days.

I notice that GFS almost always predicts lower winds than actually happen here in Iqaluit, whereas ECMWF is much closer. But I don't know that it's a broad trend rather than just being different resolution. Wind speeds are often very different on the bay versus inland; if GFS has us in a grid square that averages to being a couple km inland it would explain the issue.
Title: Re: The 2018 melting season
Post by: gerontocrat on May 09, 2018, 09:38:57 PM
Things are cooling down North of 80
Title: Re: The 2018 melting season
Post by: marcel_g on May 09, 2018, 09:48:26 PM
10 day forecast. (Max temperature.)

Personally I'd be happier if we kept this thread closer to the observations. I can wait ten days to see what happened, whereas looking forward ten days from now is a total crapshoot (especially with GFS).

Personally, I always find the "oh shit, look what's coming for the Arctic" forecasts that are a big part of the melting season threads to be valuable. Granted, the <5 day forecasts are a lot better than the 5-10 day forecasts. I guess I'm here because I want to have some clue as to what's going to happen. There is also a lot of discussion about what actually happened, and why, but the forecasts really get my curiousity going.
Title: Re: The 2018 melting season
Post by: Neven on May 09, 2018, 10:17:00 PM
Oh shit, look what's coming for the Arctic in the <5 day forecast.

1025-1030 hPa is bad enough, but it rises to 1039 hPa on day 6, and stays that way until day 10, which would be OH SHIT. It's the worst possible weather for the ice, and we're lucky that it's only mid-May. If we see this kind of weather in June, it will take some seriously cold and cloudy weather in July and August to cut the momentum short. And I will be using larger fonts for the OH SHIT.

But this is definitely oh shit.  ;)
Title: Re: The 2018 melting season
Post by: Neven on May 09, 2018, 10:22:56 PM
As expected, Barentsz is dropping off a cliff. CAB is also showing a drop, but it will probably go up again. Eyes should be kept on the Beaufort. It has been lagging a bit, but given the current forecasts the Beaufort Gyre should really start pulling the ice away from the coasts any day now.
Title: Re: The 2018 melting season
Post by: bbr2314 on May 09, 2018, 10:59:24 PM
As expected, Barentsz is dropping off a cliff. CAB is also showing a drop, but it will probably go up again. Eyes should be kept on the Beaufort. It has been lagging a bit, but given the current forecasts the Beaufort Gyre should really start pulling the ice away from the coasts any day now.
Yikes. I think the problem this year is the ATL front close to the CAB is just so open that once momentum gets going (as is now happening), we may not have enough import from the grye to negate open water reaching.... extremely.... far past 80N by 9/1.

The next week+ of weather is going to put an enormous bullseye into the heart of the pack. But on the plus side, perhaps we see more of a CAB/CAA-esque situation along the Siberian shorelines this year? The amount of ice there is quite impressive, however, it normally melts out entirely.

Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 09, 2018, 11:27:49 PM
10 day forecast. (Max temperature.)

Personally I'd be happier if we kept this thread closer to the observations. I can wait ten days to see what happened, whereas looking forward ten days from now is a total crapshoot (especially with GFS).

I agree...the short-term forecasts are of some interest in terms of figuring out what is going on at the moment and guesstimating the future, but the longer term forecasts are simply noise.
Title: Re: The 2018 melting season
Post by: numerobis on May 09, 2018, 11:50:54 PM
970 mb storm flitting by the Baffin sea on Saturday. There go my weekend plans to go skiing.
Title: Re: The 2018 melting season
Post by: JayW on May 10, 2018, 12:02:26 AM
May 5-9 Beaufort and some Chukchi, 101 hour loop.  Easterly winds north of Alaska are beginning to ramp up, and are progged to increase over the next 24 hours, persistenting for several days.  We'll see soon if anything freezes.

Contrast slightly increased for detail.  Imagery courtesy of the University of Alaska at Fairbanks.
.
http://feeder.gina.alaska.edu/npp-gina-alaska-truecolor-images?search%5Bfeeds%5D%5B5%5D=1&search%5Bsensors%5D%5B3%5D=1
Title: Re: The 2018 melting season
Post by: Michael Hauber on May 10, 2018, 12:29:20 AM
The forecast is for a big high, but for the most part it is surrounded by low pressure/troughing.  So not a lot of warm air coming from the south into the Arctic to go with all the sunshine and warming of air in place as it descends.
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 10, 2018, 02:41:43 AM
10 day forecast. (Max temperature.)

Personally I'd be happier if we kept this thread closer to the observations. I can wait ten days to see what happened, whereas looking forward ten days from now is a total crapshoot (especially with GFS).

Is GFS totally at fault ? I've just scrolled through cci-reanalyzer using the hourly forecast slider and I have seen nothing to match the image posted by Telihod. It all looked very ordinary to me - warmth and cold moving anti-clockwise around and no massive anomalies.

What does 10 day forecast max temperature mean anyway? Is this the max temperature reached over the 10 day period for a specific point on the map? If that is so, it's meaningless.
Title: Re: The 2018 melting season
Post by: Bob Wallace on May 10, 2018, 02:42:49 AM
The NSIDC has posted the correct ice age figure:

(https://vgy.me/p9OXk7.jpg)

How one plots their data can change the impact on the viewer.


(https://vgy.me/9Bii4p.jpg)

The message I would like to see made obvious is that the Arctic is running out of older ice. 
Title: Re: The 2018 melting season
Post by: jdallen on May 10, 2018, 08:14:25 AM
The NSIDC has posted the correct ice age figure:

(https://vgy.me/p9OXk7.jpg)

How one plots their data can change the impact on the viewer.


(https://vgy.me/9Bii4p.jpg)

The message I would like to see made obvious is that the Arctic is running out of older ice.
Further thought... the total thickness should be reduced by the change over time of maximum extent.  For example, while the percentage of 2nd year ice has remained more steady than the other ages, its absolute coverage has declined by between 30-40% since the start of the time period in question.

I'm looking for numbers....
Title: Re: The 2018 melting season
Post by: Bob Wallace on May 10, 2018, 08:55:33 AM
So we need a widening band of white along the top.

"In Memory of Ice That Used To Be"

If you don't find numbers I can create a version where the color part gets squeezed down 30% to 40% from left to right.  It wouldn't be as accurate as year to year but it would make conditions more apparent.
Title: Re: The 2018 melting season
Post by: Dave C on May 10, 2018, 09:23:58 AM
Can the Bremen map possibly be accurate?

The ice has never melted by the pole. I can't remember it even being that thin before, let alone in May.

(https://seaice.uni-bremen.de/data/amsr2/today/Arctic_AMSR2_nic.png)
Title: Re: The 2018 melting season
Post by: oren on May 10, 2018, 10:26:52 AM
]
Further thought... the total thickness should be reduced by the change over time of maximum extent.  For example, while the percentage of 2nd year ice has remained more steady than the other ages, its absolute coverage has declined by between 30-40% since the start of the time period in question.

I'm looking for numbers....
If you're looking for thickness distribution over time, Wipneus posted just such a chart in the PIOMAS thread a few days ago. Ice age is more difficult, but one could take NSIDC ice area on the ninth week every year, and use that as a scaling factor over the NSIDC graph.
Title: Re: The 2018 melting season
Post by: Steven on May 10, 2018, 11:34:55 AM
the total thickness should be reduced by the change over time of maximum extent.  For example, while the percentage of 2nd year ice has remained more steady than the other ages, its absolute coverage has declined by between 30-40% since the start of the time period in question.

Maximum sea ice extent has decreased by about 10% since the early 1980s:

http://nsidc.org/arcticseaicenews/files/2018/04/Figure3.png

Moreover, the NSIDC ice age graph uses an Arctic Ocean domain (https://i.imgur.com/KqhXhyo.png) that excludes regions like Bering, Okhotsk, Baffin, Greenland Sea, etc.  The decrease in maximum sea ice extent for that domain is about 5% rather than 10%.
Title: Re: The 2018 melting season
Post by: Vergent on May 10, 2018, 11:58:01 AM
Long range GFS will keep bouncing around, it keeps showing similar potentialities.

(https://i.imgur.com/t5MUuXc.png)

Verg

edit: I think it has something to do with the second law of thermodynamics.
Title: Re: The 2018 melting season
Post by: Neven on May 10, 2018, 01:39:47 PM
Can the Bremen map possibly be accurate?

The ice has never melted by the pole. I can't remember it even being that thin before, let alone in May.

These are usually artifacts caused by clouds or melt ponds or glitches or whatever. My rule of thumb is: The yellow/green colours need to persist in the same place for at least three days. If that's the case, it may be that there is ice divergence there due to melting and/or winds.

BTW, if you want to see if something happened before, or when, you can compare concentration maps on this special page on the Arctic Sea Ice Graphs page (pick a date): Concentration Maps (https://sites.google.com/site/arcticseaicegraphs/concentration-maps).
Title: Re: The 2018 melting season
Post by: meddoc on May 10, 2018, 01:53:54 PM
Long range GFS will keep bouncing around, it keeps showing similar potentialities.

edit: I think it has something to do with the second law of thermodynamics.

Oh, You don't say.
The whole Heat Transport and GHG- Effect and in Reality, everything is governed by the I & II Laws of Thermodynamics. We know where we are headed. Only the Time left is the Question. But, surely no turning around.

Everything else is just Politics.
Title: Re: The 2018 melting season
Post by: friedmators on May 10, 2018, 02:03:55 PM
10 day forecast. (Max temperature.)

Personally I'd be happier if we kept this thread closer to the observations. I can wait ten days to see what happened, whereas looking forward ten days from now is a total crapshoot (especially with GFS).

Is GFS totally at fault ? I've just scrolled through cci-reanalyzer using the hourly forecast slider and I have seen nothing to match the image posted by Telihod. It all looked very ordinary to me - warmth and cold moving anti-clockwise around and no massive anomalies.

Slightly OT, but the GFS has a hurricane in the Gulf of Mexico in about 12 days...Not sure how the verification scores line up in the Arctic versus globally, but that model has issues.
Title: Re: The 2018 melting season
Post by: Vergent on May 10, 2018, 03:32:44 PM
10 day forecast. (Max temperature.)

Personally I'd be happier if we kept this thread closer to the observations. I can wait ten days to see what happened, whereas looking forward ten days from now is a total crapshoot (especially with GFS).
Is GFS totally at fault ? I've just scrolled through cci-reanalyzer using the hourly forecast slider and I have seen nothing to match the image posted by Telihod. It all looked very ordinary to me - warmth and cold moving anti-clockwise around and no massive anomalies.

Slightly OT, but the GFS has a hurricane in the Gulf of Mexico in about 12 days...Not sure how the verification scores line up in the Arctic versus globally, but that model has issues.

You have to read the caption "10 day max temperature". It can be found in the outlook section

http://cci-reanalyzer.org/wx/fcst_outlook/

Verg

edit: placement
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 10, 2018, 03:43:22 PM
So we need a widening band of white along the top.

"In Memory of Ice That Used To Be"

If you don't find numbers I can create a version where the color part gets squeezed down 30% to 40% from left to right.  It wouldn't be as accurate as year to year but it would make conditions more apparent.

That chart would be powerful.
Title: Re: The 2018 melting season
Post by: jdallen on May 10, 2018, 03:43:39 PM
the total thickness should be reduced by the change over time of maximum extent.  For example, while the percentage of 2nd year ice has remained more steady than the other ages, its absolute coverage has declined by between 30-40% since the start of the time period in question.

Maximum sea ice extent has decreased by about 10% since the early 1980s:

http://nsidc.org/arcticseaicenews/files/2018/04/Figure3.png

Moreover, the NSIDC ice age graph uses an Arctic Ocean domain (https://i.imgur.com/KqhXhyo.png) that excludes regions like Bering, Okhotsk, Baffin, Greenland Sea, etc.  The decrease in maximum sea ice extent for that domain is about 5% rather than 10%.
Excellent points. Makes the need for my adjustment less necessary.
Title: Re: The 2018 melting season
Post by: jdallen on May 10, 2018, 03:49:52 PM
Can the Bremen map possibly be accurate?

The ice has never melted by the pole. I can't remember it even being that thin before, let alone in May.

These are usually artifacts caused by clouds or melt ponds or glitches or whatever. My rule of thumb is: The yellow/green colours need to persist in the same place for at least three days. If that's the case, it may be that there is ice divergence there due to melting and/or winds.

BTW, if you want to see if something happened before, or when, you can compare concentration maps on this special page on the Arctic Sea Ice Graphs page (pick a date): Concentration Maps (https://sites.google.com/site/arcticseaicegraphs/concentration-maps).
What Neven said.

I'll add, we have seen lower concentration at the pole before. 2013 stands out in my mind particularly in that regard, so it is not unheard of.

We haven't yet had a true "blue water" event at the pole either (no ice at 90N as far as the eye can see), though we have come close .

I'm far less concerned about that than I am the condition of the ice in the system as a whole.
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 10, 2018, 05:03:35 PM
It's looking like most likely for min extent is under 4 million:
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 10, 2018, 05:07:16 PM
Jaxa is more like exactly 4 million on average:
Title: Re: The 2018 melting season
Post by: jdallen on May 10, 2018, 07:58:09 PM
Jaxa is more like exactly 4 million on average:
One of the consequences of lower maxes is the appearance of less ice loss on an annual basis.  I think the loss of winter ice in peripheral seas has made analysis based on annual statistical methods far less skillful.

I'm wondering if we might find it useful to drop some peripheral seas from what now really is an analysis of changing conditions in the CAB, CAA, Beaufort, ESS, Chukchi and Laptev.  The rest either melt out completely now, or do not fully refreeze, or both, which I think skews our perception of what is happening.
Title: Re: The 2018 melting season
Post by: Niall Dollard on May 10, 2018, 08:05:03 PM
It's looking like most likely for min extent is under 4 million:

Similar predictions on both. And it looks reasonable, but a lot can happen especially over next 8 weeks, will tell a lot.

The year date on the chart based on NSIDC data needs to be changed.
Title: Re: The 2018 melting season
Post by: Neven on May 10, 2018, 10:00:14 PM
The ice in the Beaufort Sea is about to pull away from the Canadian and Alaskan coasts:
Title: Re: The 2018 melting season
Post by: subgeometer on May 11, 2018, 05:13:12 AM
It will be interesting to see how long all the recent refreeze out from the coast of Alaska will last. And the glue ice. A lot of the Beaufort rapidly turned to mush last year.

There's also a lot of thin ice in the Laptev Sea beyond the fast ice . It's still just cold enough for refreeze there as ice is exported but there will be open water there before long. I've made an animation of the last 5 days to see through the partial cloud.

Around the line between fast and mobile ice, particularly north of the New Siberian Islands NOAA's sst chart has shown persistent and spreading warm anomalies. I'm not sure how this is derived or inferred. Is it Atlantification? I've got a chart from 10 June last year(closest date I can find) which is quite similar around the area
Title: Re: The 2018 melting season
Post by: Wherestheice on May 11, 2018, 05:36:15 AM
Jaxa is more like exactly 4 million on average:

I wouldn't pay to much attention to predictions like that. So much can change in short amounts of time. Really all that is, is a bunch of numbers being crunched together. 
Title: Re: The 2018 melting season
Post by: binntho on May 11, 2018, 04:47:44 PM
Been looking at the Mackenzie river and it's starting to break ice cover some 700-800 km from the coast. But near the small town of Tsiigehtchic (some 150 km from the coast) the Arctic Red River seems to have cleared itself.

Just 10km downstream from Tsiigehtchic the Mackenzie river exits the low hills (moraines) and there, to the east of the river, a lot of water seems to be accumulating. I've marked the edge of the moraines with red, the black area to the northeast is probably water.

In Norway the melt is off to a cracking start, as show in the video in this article (https://www.nrk.no/ho/e6-kan-bli-stengt-pa-kort-varsel-1.14046239).

EDIT: The black lettering disappears, but the arrow points at Tsiigehtchic, at the confluence of the Mackenzie and the Arctic Red River.
Title: Re: The 2018 melting season
Post by: Neven on May 11, 2018, 10:47:02 PM
Ice drift and speed for the coming week (click to animate):
Title: Re: The 2018 melting season
Post by: FishOutofWater on May 11, 2018, 11:09:57 PM
The winds would favor export out through the Nares Strait but I doubt the ice arch will break just yet.

The ECMWF and GFS diverge but they both predict warmth and easterly winds across the north shore of Alaska. This will help bring on early melt in the Beaufort like we have seen in recent years.
Title: Re: The 2018 melting season
Post by: meddoc on May 12, 2018, 09:08:36 AM
I doubt that the Ice by Trends alone is headed straight down to Zero this Year- but the Real Question is:
maybe it is enough to just go below- let's say 2- 2,5 M km2- to let the Cap fly off of all that Methane Hydrate lying underneath (i.e: Global Catastrophy).
Or just to have a couple of consecutive Years with exposed substantial Surface of the Arctic Ocean...
Title: Re: The 2018 melting season
Post by: johnm33 on May 12, 2018, 11:01:50 AM
Can the Bremen map possibly be accurate? -snip-
Looks like some warm Atlantic water moved west north of greenland, and moves still (https://seaice.uni-bremen.de/databrowser/#day=6&month=4&year=2018&img={%22image%22:%22image-1%22,%22sensor%22:%22AMSR%22,%22type%22:%22nic%22,%22region%22:%22Arctic%22}).
Title: Re: The 2018 melting season
Post by: Alexander555 on May 12, 2018, 12:26:33 PM
It's pretty amazing how much happend is just the few last years. If you look at these average temperature pics . It's only in the last few years that the temperature stayed north of the average the entire winter.
Title: Re: The 2018 melting season
Post by: Neven on May 12, 2018, 12:55:43 PM
Not that I have a great amount of confidence in GFS temperature forecasts, but the current one is running pretty anomalously warm:

http://pamola.um.maine.edu/wx_frames/gfs/arc-lea/t2anom/mp4/gfs_arc-lea_t2anom_2018-05-10-12z.mp4
Title: Re: The 2018 melting season
Post by: oren on May 12, 2018, 01:20:15 PM
Looking at Wipneus' animation on the AMSR2 thread, the clear area north of Svalbard has grown substantially in the last few days, and lots of ice in the Barents seems to have winked out. Also the Chukchi thin ice zone seems to have taken a big hit.
Title: Re: The 2018 melting season
Post by: meddoc on May 12, 2018, 02:10:53 PM
Not that I have a great amount of confidence in GFS temperature forecasts, but the current one is running pretty anomalously warm:

http://pamola.um.maine.edu/wx_frames/gfs/arc-lea/t2anom/mp4/gfs_arc-lea_t2anom_2018-05-10-12z.mp4

Indeed. Antarctica meanwhile has also seen pretty anomalously warm Temps.
Of course, there the Situation is not that acute as with the Arctic...
Title: Re: The 2018 melting season
Post by: gerontocrat on May 12, 2018, 02:11:44 PM
Not that I have a great amount of confidence in GFS temperature forecasts, but the current one is running pretty anomalously warm:
What also interested me was the succession of lows due to cross the  Atlantic are not forecast to reach Western Europe but to head north up between Greenland and Scandinavia. Presumably relatively warm winds and a bit of rain will be consistently shovelling warm air and warm sea up towards the frozen heart of the Arctic Ocean.

ps: The UK Metoffice says really dry in England for the next two weeks - hoorah!.
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 12, 2018, 02:54:56 PM
It's pretty amazing how much happend is just the few last years. If you look at these average temperature pics . It's only in the last few years that the temperature stayed north of the average the entire winter.

The Arctic Climate changed to a Maritime Climate on about December 29th 2015.
Title: Re: The 2018 melting season
Post by: Neven on May 12, 2018, 03:05:13 PM
The Arctic Climate changed to a Maritime Climate on about December 29th 2015.

Yes, I remember that day well. The sea breeze wafting in...
Title: Re: The 2018 melting season
Post by: Juan C. García on May 12, 2018, 03:12:19 PM
The Arctic Climate changed to a Maritime Climate on about December 29th 2015.
Yes, I remember that day well. The sea breeze wafting in...

I am not able to see the image...
Title: Re: The 2018 melting season
Post by: binntho on May 12, 2018, 03:58:41 PM
Juan, I don't think there is an image for you to see (I can see from your screenshot what seems to be a missing image, but I'm not seeing that). Anyway,  I think Neven is just being a bit off-topically sarcastic and any image would have been in the same vein (or vain?).
Title: Re: The 2018 melting season
Post by: gerontocrat on May 12, 2018, 04:47:31 PM
The Arctic Climate changed to a Maritime Climate on about December 29th 2015.
Yes, I remember that day well. The sea breeze wafting in...

I am not able to see the image...
On the 29th December 2015 the Arctic was too dark for the photo to come out. Another scoop missed.
Title: Re: The 2018 melting season
Post by: Alexander555 on May 12, 2018, 04:56:43 PM
What would be the impact of this ? Can it push the ice out of Baffin ? It has 25 feet waves. But it's making a circle.
Title: Re: The 2018 melting season
Post by: FishOutofWater on May 12, 2018, 05:12:45 PM
Yes, ice in the southwestern Labrador sea is going to take a beating with winds and waves. Central and northern Baffin bay, however, will not be affected today by the storm near the south tip of Greenland.

The ice in the Beaufort sea will also take a beating with warm easterly winds and Ekman upwelling.
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 12, 2018, 05:22:29 PM
Is there enough Sun yet for the high over most of the Arctic Ocean to really count?
Title: Re: The 2018 melting season
Post by: uniquorn on May 12, 2018, 05:29:21 PM
A look back at Beaufort Sea for previous years on this date. Worldview terra/modis May11, 2000-2018.

bottom left corner of 2012 image flood filled
Title: Re: The 2018 melting season
Post by: charles_oil on May 12, 2018, 05:47:38 PM
Uniquorn - Great Gif - like the pause at the end.  Doesn't look like any particular pattern emerges - seems almost random....
Title: Re: The 2018 melting season
Post by: uniquorn on May 12, 2018, 06:30:14 PM
Random, like weather.
DMI ice surface temperature for the current melting season. Mar22-May11

I forgot mar21
Title: Re: The 2018 melting season
Post by: oren on May 12, 2018, 08:07:12 PM
Uniquorn thanks for the animation. 2016 had a horrible season start in the Beaufort, this year is more focused on the Chukchi and is still lagging behind overall. Hopefully it will keep on lagging.
Title: Re: The 2018 melting season
Post by: numerobis on May 12, 2018, 08:07:42 PM
What would be the impact of this ? Can it push the ice out of Baffin ? It has 25 feet waves. But it's making a circle.

The impact is I'm staying indoors while my partner goes skiing with friends, because I can't stand being in 40+ km/h winds. I went outside for five minutes to sand a piece of wood and even that was uncomfortable for me (but the wind was fantastic at blowing the sawdust away while I worked).

For the ice: it's bringing up much warmer temperatures, while simultaneously making it cloudy (i.e. less sun). The storm is blowing by quickly, I'm not sure if we should expect it to do much.

Not entirely related: I stuck my foot in a snow-covered melt pond yesterday while walking out on the sea.
Title: Re: The 2018 melting season
Post by: Neven on May 12, 2018, 08:33:29 PM
I am not able to see the image...

The image is there now, but it's not so important. I was just goofing around.  ;D
Title: Re: The 2018 melting season
Post by: subgeometer on May 13, 2018, 03:18:46 AM
Extent is tracking 2016 without the the Beaufort (or the Kara) opening up - yet. So that doesn't seem like a good place to be.

Beaufort liftoff has now commenced, and drift projection for next few days posted by Neven indicates it will proceed with gusto
Title: Re: The 2018 melting season
Post by: subgeometer on May 13, 2018, 04:38:46 AM
After some wrestling with ffmpeg I've been able to create some movies (rather than gifs) from stills from worldview.

It's been practically cloud free over the Beaufort Sea recently allowing a closer look at the ice, which skows a lot of thin translucent ice between the more solid floes. There's nothing much to inhibit ice movement, and that thin stuff can't last long with constant sun and warm air intrusions.

I've included an animation of a section of the Beaufort Sea( between 71-74 north) from May 6-12, as well as a slightly blown up still from may 11 where the "glue ice" is clearly visible

edit: the first movie wouldn't display, changed the output encoding( to mpeg4 - which again doesn't display - at least in my firefox/ubuntu setup. I'll leave it for now in case others can see it - it plays fine locally)
Title: Re: The 2018 melting season
Post by: miki on May 13, 2018, 05:26:20 AM
edit: the first movie wouldn't display, changed the output encoding( to mpeg4 - which again doesn't display - at least in my firefox/ubuntu setup. I'll leave it for now in case others can see it - it plays fine locally)

Thanks. I was able to download it. Really clear.
Title: Re: The 2018 melting season
Post by: subgeometer on May 13, 2018, 06:45:37 AM
Fracturing and liftoff is also happening northeast of Greenland.

I've attached a gif and mp4 of the same images from may 9 to 12- with Kronprins Christian Land(!) at the far north east tip of Greenland at the bootom. This area is forecast to see near or above freezing conditions over the next few days with winds blowing mostly from the south east

technical note:
(the movie is higher res but a smaller file, I left encoding to the software which used libx264 - let's see if it displays. Any links to a discussion on movie output and playback issues would be appreciated)
Title: Re: The 2018 melting season
Post by: meddoc on May 13, 2018, 09:18:04 AM
Not good Signs. Coupled with the forecasted Heat for all the Periphery it's going to set up Things for  Big Melt.
Title: Re: The 2018 melting season
Post by: Neven on May 13, 2018, 10:06:18 AM
The forecast looks slightly better than it did a few days ago, but far from good (and D6-10 still looks pretty awful). One upside is that there is very little Fram transport.
Title: Re: The 2018 melting season
Post by: Neven on May 13, 2018, 10:13:08 AM
Sea surface temperature anomalies, May 12th, 2012 vs 2018:
Title: Re: The 2018 melting season
Post by: Niall Dollard on May 13, 2018, 11:48:49 AM
Thanks Neven.

Looking at that I would have to say there is little sign of a weakening NAD (at surface level). Certainly the west spitzbergen current is strong.
Title: Re: The 2018 melting season
Post by: VeliAlbertKallio on May 13, 2018, 02:50:58 PM
Melting or No Melting? At least the non-news of Paris Agreement melting in Bonn in a small print. China to follow the example set by US President Trump to pull out. More ice to melt, surely?
http://www.bbc.co.uk/news/science-environment-44074352 (At least UN seems in no hurry.)  :-[
Title: Re: The 2018 melting season
Post by: uniquorn on May 13, 2018, 02:53:26 PM
Windy ECMWF WAM wave forecast for may17.
I'm not sure of the forum's views on WAM but it seems broadly in agreement with winds forecast by ECMWF and GFS.
Title: Re: The 2018 melting season
Post by: gerontocrat on May 13, 2018, 03:00:46 PM
Windy ECMWF WAM wave forecast for may17.
I'm not sure of the forum's views on WAM but it seems broadly in agreement with winds forecast by ECMWF and GFS.
Seems to match pretty well where the GFS forecast for May 17 (from cc-reanalyzer) seems to say the warmth will be (first image attached).

Once again GFs also says a major warming event 9 days out (second image). I suppose, like the Farmer's Alamanac, they have to be right sometime?
Title: Re: The 2018 melting season
Post by: FishOutofWater on May 13, 2018, 03:05:30 PM
There pretty much a consensus of models. The GFS and CFSv2 models run hot in the Arctic, but this time they are not out there by themselves.
Title: Re: The 2018 melting season
Post by: meddoc on May 13, 2018, 04:42:33 PM
Melting or No Melting? At least the non-news of Paris Agreement melting in Bonn in a small print. China to follow the example set by US President Trump to pull out. More ice to melt, surely?
http://www.bbc.co.uk/news/science-environment-44074352 (At least UN seems in no hurry.)  :-[

UN is always lagging behind by at least 100 Years, when it comes to Global Action.
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 13, 2018, 05:19:48 PM
Melting or No Melting? At least the non-news of Paris Agreement melting in Bonn in a small print. China to follow the example set by US President Trump to pull out. More ice to melt, surely?
http://www.bbc.co.uk/news/science-environment-44074352 (At least UN seems in no hurry.)  :-[

UN is always lagging behind by at least 100 Years, when it comes to Global Action.

The 2 largest economies on the planet playing a game of chicken.

The sad truth is that all of us, rich and poor alike, are going to end up like this...
Title: Re: The 2018 melting season
Post by: GoSouthYoungins on May 13, 2018, 05:43:49 PM
Melting or No Melting? At least the non-news of Paris Agreement melting in Bonn in a small print. China to follow the example set by US President Trump to pull out. More ice to melt, surely?
http://www.bbc.co.uk/news/science-environment-44074352 (At least UN seems in no hurry.)  :-[

UN is always lagging behind by at least 100 Years, when it comes to Global Action.

I'm quite certain that is the point. 

Any thoughts on the accuracy of the 80%ish concentration where CAB and CAA meet? Seems to be persisting in Bremen but not NSIDC, which makes be think inaccurate.
Title: Re: The 2018 melting season
Post by: Jontenoy on May 14, 2018, 10:09:51 AM
Has anyone got a graph of Sea Ice volume ?
Although sea ice extent following 2016, perhaps the volume is diminished ?
Title: Re: The 2018 melting season
Post by: oren on May 14, 2018, 12:21:57 PM
Has anyone got a graph of Sea Ice volume ?
Although sea ice extent following 2016, perhaps the volume is diminished ?
Check out the PIOMAS thread for a volume graph, it is updated twice every month. PIOMAS is the most reliable measure of arctic sea ice volume. You will notice volume is higher than 2016, giving hope that extent drops will slow down at some point, but that volume distribution is such that some of the extra volume is also at extra risk.
https://forum.arctic-sea-ice.net/index.php/topic,119.msg153019.html#msg153019 (https://forum.arctic-sea-ice.net/index.php/topic,119.msg153019.html#msg153019)
Title: Re: The 2018 melting season
Post by: Jim Pettit on May 14, 2018, 12:43:01 PM
FREQUENT REMINDER: as one of the more popular threads, it's especially important to stay on-topic here. PLEASE discuss only the 2018 melting season here; comments on other topics belong elsewhere.

Thanks!
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 14, 2018, 03:39:17 PM
Sorry Jim. My fault.
Title: Re: The 2018 melting season
Post by: BenB on May 14, 2018, 04:25:16 PM
This is still a bit far out to be reliable, but if it's close to true, it should get melt-pond May going strongly, with temperatures above zero across large swathes of the Arctic:

(https://keytwist.net/floe/external/t2/56.png/)
(https://keytwist.net/floe/external/t2anom/56.png/)

A 3.6 degree anomaly would be very unusual for this time of year - perhaps unprecedented? Either way, temperatures are forecast to be high over the coming few days, with the anomaly growing day by day, so we should see some acceleration in melting over the coming week.
Title: Re: The 2018 melting season
Post by: jdallen on May 14, 2018, 07:09:03 PM
This is still a bit far out to be reliable, but if it's close to true, it should get melt-pond May going strongly, with temperatures above zero across large swathes ....
Revisit this in two days and see how it shifts.
Title: Re: The 2018 melting season
Post by: Random_Weather on May 14, 2018, 07:27:39 PM
jdallen,

Correct, GFS is strongly warm biased with time, since years i watch this, therefore i think its an issue with snow cover..

also see: http://www.karstenhaustein.com/reanalysis/gfs0p5/ANOM2m_arctic/verification/ANOM2m_bias_past07_arctic.html

to the +168h forecast, there is a massive warm bias to the past 7 days

Also evident over the full northern hemisphere: http://www.karstenhaustein.com/reanalysis/gfs0p5/ANOM2m_mollw/verification/ANOM2m_bias_past07_mollw.html
Title: Re: The 2018 melting season
Post by: dnem on May 14, 2018, 08:01:57 PM
Incredibly useful graphic, Random.  Thank you for posting.
Title: Re: The 2018 melting season
Post by: Neven on May 14, 2018, 10:08:45 PM
Definitely useful. GFS as usual running hot beyond 3 days out.

As for ECMWF sea level pressure, D1-6 looks just a tiny bit worse than it did yesterday, all days are 1030+ hPa. But on the flip side D7-10 is looking up, even though high pressure still dominates the CAB (but we try not to look too much beyond Day 6, so I'm not posting it):
Title: Re: The 2018 melting season
Post by: gerontocrat on May 14, 2018, 11:16:02 PM
Longyearbyen, Svalbard weather forecast attached. Is this warm for the time of year, or just average?
Title: Re: The 2018 melting season
Post by: uniquorn on May 15, 2018, 12:43:30 AM
The wave forecast got a bit stronger for thursday north of Svalbard
Title: Re: The 2018 melting season
Post by: Aluminium on May 15, 2018, 12:46:02 AM
Longyearbyen, Svalbard weather forecast attached. Is this warm for the time of year, or just average?
In Barentsburg the weather is much warmer than average. I use this site (http://www.pogodaiklimat.ru/monitor.php?id=20107) (in Russian). The average temperature is normally below zero until the end of May.
Title: Re: The 2018 melting season
Post by: JayW on May 15, 2018, 03:00:49 AM
Beaufort Sea May 9-13, 102 hours. Contrast boosted for detail, I also find it makes it easier to distinguish the clouds from the surface.

http://feeder.gina.alaska.edu/npp-gina-alaska-truecolor-images?search%5Bfeeds%5D%5B5%5D=1&search%5Bsensors%5D%5B3%5D=1
Title: Re: The 2018 melting season
Post by: BenB on May 15, 2018, 11:55:17 AM
I'm well aware of the problems with GFS at those time scales, but 3.6 seemed pretty extreme for this time of year, even by its standards. Anyway, the point was more that the next week looks consistently warm, and even subtracting a 1.6 correction factor for 168 hours, you get a 2 degree anomaly. Speaking of which, the more reliable 3-day forecast is for a 2.2 anomaly:

(https://keytwist.net/floe/external/t2anom/24.png/)

Title: Re: The 2018 melting season
Post by: Neven on May 15, 2018, 12:05:27 PM
Ben, you may be right. There may be something there. Another heat pulse, while high pressure keeps dominating, would be another early blow to the ice.
Title: Re: The 2018 melting season
Post by: BenB on May 15, 2018, 12:45:03 PM
And I may be wrong  ;) But May seems interesting this year - whereas in recent years DMI has tended to follow the mean temperature very closely at this time of year (or even dip below it), this year we've stayed consistently warmer. Now this heat pulse may be coming at a time when temperatures and insolation are high enough to cause some real damage, and potentially get the melt season in the CAB off to the fast start that it hasn't really seen recently in terms of melt-ponding and pre-conditioning the ice.

At the same time, we have very high sea surface temperature surface anomalies, which if they continue to build will cause damage at the end of the season. It will be interesting to watch how things develop.
Title: Re: The 2018 melting season
Post by: S.Pansa on May 15, 2018, 01:06:41 PM
Here is another model-view on the things that might come to the Arctic. The first pic compares ESRL & GFS forecasts for temps and SLP.
In agreement with the ECMWF-forecast posted by Neven above they show the high pulling back to the Beaufort. That could make room for a little heat intrusion over the ESS and Laptev. The forecasted SLP is in good agreement, the surface temps differ slightly  ;)

The two other pics show the predicted melt pond fraction. First pic from today has some ponds in the Chukchi/Beaufort. The second shows the possible consequences of the predicted little heat wave: widespread meltponding in the ESS/Laptev.

Bad news for the ice? Who knows. Fortunately the SPIE (http://cires1.colorado.edu/~aslater/SEAICE/) of the great late professor Slater is back online (maintained now by Andrew Barret's team at NSIDC as I gather from this guest post (http://neven1.typepad.com/blog/2017/08/guest-blog-arctic-prediction-models.html) at the ASIB).
Will be interesting to see if this forecast materializes and how this will effect Slaters model.

PS: A late thanks to Dryland for the effort and the link to his site (https://floe.keytwist.net/), wehre he has put together the most interesting ESRL model outputs
Title: Re: The 2018 melting season
Post by: Neven on May 15, 2018, 01:13:39 PM
Beaufort Sea May 9-13, 102 hours. Contrast boosted for detail, I also find it makes it easier to distinguish the clouds from the surface.

And we'll have at least another week of this... Spectacular images, but bad for the ice.
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 15, 2018, 03:26:31 PM
Is that clouds or is there a little bit of refreeze in the Beaufort as the ice fractures and separates?
Title: Re: The 2018 melting season
Post by: FishOutofWater on May 15, 2018, 03:36:43 PM
The Greenland low pressure vortex, Arctic ocean high pattern will continue for the next week according to the ECMWF model. This weather pattern enhances transport of both atmospheric and ocean heat from the subtropics in the Atlantic towards Europe's subpolar seas. This pattern has already rapidly warmed the waters in the Norwegian and Barents seas in the first two weeks of May.

Now it will be warm enough and the sunlight will be intense enough for melting of snow on top of the ice to begin under the dome of high pressure over the Arctic.

Slater's model is incorporating this pattern into its prediction of an ice area/extent cliff in the first week of July.
Title: Re: The 2018 melting season
Post by: numerobis on May 15, 2018, 04:00:56 PM
Looks to me like the high Arctic is getting hammered this May, whereas the lower-latitude Arctic is running a bit cool and cloudy.

Down here it'll all melt out regardless.
Title: Re: The 2018 melting season
Post by: Lord M Vader on May 15, 2018, 04:15:57 PM
Wrt to Slaters model which foresees an SIE of 9,18 Mn km2 by July 4. It's worth to remember that the SIE for July 4 last year was 9,174 Mn km2.... A number of 9,18 is just a fourth place.

The main question is whether the high pressure is able to remain in the CAB and adjacent areas through June. The GFS weekly forecasts hints of a high pressure dominated weather over the Siberian side by the end of May and beginning of June. That would be a rather interesting set up as the ice this year is considerably thicker on the Siberian side while thinner at the North American side and close to the pole.
The forecast for week 4 (June 5-11) is very far away but GFS have been rather consistent for the last few days and believes in a continuation of HP over the Siberian side.
Title: Re: The 2018 melting season
Post by: Gray-Wolf on May 15, 2018, 06:54:21 PM
I think once High Pressure is established changes occur only slowly. Lows are far more 'dynamic' and so more difficult to forecast for any area?

Should there be a physical reason why we see HP dominance over winter in the north Atlantic across low solar then it would be interesting to see if such a forcing maintains in summer but migrates further north with the changing of the seasons?

Any 'extra push' toward H.P. over summer in the basin would be most unwelcome!!!
Title: Re: The 2018 melting season
Post by: romett1 on May 15, 2018, 07:16:02 PM
Small update about FDD (Freezing Degree Days) anomaly north of 80° N between Jan 01 and May 14. May has been significantly warmer than 2017 and looking at the weather forecast it is possible that 2016 level (since start of the year) may be reached. Image: https://sites.google.com/site/cryospherecomputing/fdd
Title: Re: The 2018 melting season
Post by: JayW on May 16, 2018, 02:52:13 AM
Is that clouds or is there a little bit of refreeze in the Beaufort as the ice fractures and separates?

There's certainly low clouds, especially today.  I wouldn't rule out some freezing over of leads locally, but it's my opinion that it's mostly clouds, perhaps entirely.

Here's the "landcover" band from VIIRS.  May 12-15, ~81 hours

http://feeder.gina.alaska.edu/npp-gina-alaska-landcover-images?search%5Bfeeds%5D%5B6%5D=1&search%5Bsensors%5D%5B3%5D=1
Title: Re: The 2018 melting season
Post by: FrostKing70 on May 16, 2018, 07:06:15 PM
Interesting.   Those are some large gaps developing....
Title: Re: The 2018 melting season
Post by: Michael Hauber on May 17, 2018, 12:47:21 AM
Visually on MODIS, I cannot find nearly as much red (surface melting) in the channel 3-6-7 as 2016 at same date.  But a lot more cloud - foggy conditions under high pressure?  Not sure if this fog is hiding surface melting or if its reflecting sunlight and delaying the start of surface melt.

I'm sure temps are warm, and melting early, compared to the longer term average.  But compared to recent years?  Not sure.  But I can't imagine it being at the cooler end, either middle or warmer.
Title: Re: The 2018 melting season
Post by: A-Team on May 17, 2018, 02:24:49 AM
Up-forum, the NSIDC's sea ice age comparison for 'week nine' of 1984/2018 includes the Barents, Kara and even White Sea [Белое море] as part of the Arctic Ocean whereas we are primarily exercised with the Arctic Ocean proper: north of the Svalbard - FJL - SZ line (or a bit more inclusively north of 80ºN) in this region.

http://nsidc.org/arcticseaicenews/files/2018/05/Figure_4ad_correctedV2-985x1024.png

Their graph makes its point well enough: the older ice classes are pinching out to zero as first and second year ice come to predominate. However what is the quantitative effect of diluting the AO ice class areas with these peripheral seas that never have so much as SYI?

The Barents etc comprise some 31% of the total area but as the consolidated graphic below shows, it was almost entirely open water already in 1984 on this date, The Kara was filled with FYI in both years. However there's tremendous variability in the Barents ice cover and 1984 is not all that representative.

Thus an overly broad definition of 'Arctic Ocean' contributes quite a bit of noise to the ice age trend, just as it does to extent, area, concentration and volume trends. At some venues (such as Piomas), individual sub-regions have been dissected out and plotted separately. Elsewhere, whole northern hemisphere tracking remains at cross-purposes with near-term prediction.

Note open water (0YI?) at 'week nine' is not allocated space on the NSIDC graph. That really should be fixed because even restricting to the Arctic Ocean proper, 0YI now occurs all year above Svalbard (not just during mid-winter 'week nine' of 2018). Indeed, Jaxa shows open water there in all years archived, back to 2003.

Open water, averaged over this date for 14 years, is shown in last frame. No trend is seen (or expected) because wind-blown ice can easily predominate in the northern Barents.

Up-forum, I've explained how and why NSIDC should refine the FYI and SYI ice age classes down to  a monthly basis (or age since attainment of 0.5m and 1m SMOS thicknesses). Tracking ice provenance is quite important to understanding melt season susceptibility.

NSIDC makes these ice age classes by tracking parcels in Ascat imagery (ie radar roughness development), so I've attached the 2018 time series from day 1 to day 63 (Mar 4th) through day 135 (May 15), along with the Jaxa counterpart. Ascat data has had a very bumpy ride to NOAA archives lately so data gaps in MetopA are repaired here with MetopB in the mp4 below.

Jaxa is complementary to Ascat in terms of wavelength and polarity but provides less surface feature acuity. That's offset by its much richer channel dimensionality and potential for detecting snow melt, melt ponds, drained melt ponds, or wave-washed floes.

While fiducial training sets are in short supply, a peculiar region north of FJI showing persistent pink (resp. green in inverse; final rest frame) for the last five days -- ruling out weather artifacts -- deserves further interpretative scrutiny. It is shown as thin ice in the PR89 polarization ration product at Jaxa.

https://ads.nipr.ac.jp/vishop/#/monitor

http://www.ospo.noaa.gov/data/atmosphere/ascat/MetopA/ICE/msfa-NHe-a-2018135.sir.gif
Title: Re: The 2018 melting season
Post by: numerobis on May 17, 2018, 05:36:32 AM
Local news mentions Frobisher Bay’s flow edge is closer to torn than usual:
http://nunatsiaq.com/stories/article/65674floe_edge_near_iqaluit_thinner_and_closer_than_usual_canadian_/

Along with generic ice-is-thinner-and-younger that we all know.
Title: Re: The 2018 melting season
Post by: Telihod on May 17, 2018, 07:19:17 AM
I wonder if the ice north of Greenland could melt completely this year (if it is not replaced from somewhere else), since positive temperatures are a regular thing there (and the ice is thinner than usual)?


Title: Re: The 2018 melting season
Post by: subgeometer on May 17, 2018, 10:53:56 AM
I think we'll see signs of melt ponding soon on the fast ice by the the ESS coast, maybe starting in the big bay. The ECWMF forecast shows well above freezing temps at 925hPa all week, as well as at the surface. The GFS also has Siberia warming a lot
Title: Re: The 2018 melting season
Post by: JayW on May 17, 2018, 12:04:10 PM
925mb reanalysis temp anomaly from April 14-May 14, 2018.

https://www.esrl.noaa.gov/psd/data/composites/day/
Title: Re: The 2018 melting season
Post by: charles_oil on May 17, 2018, 01:59:10 PM
JayW - it looks like the temp scale maxes out at 5+ degrees on the 14th temp anomaly so I imagine there are contours of even greater anomalies within the bullseyes too....
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 17, 2018, 04:31:20 PM
I wonder if the ice north of Greenland could melt completely this year (if it is not replaced from somewhere else), since positive temperatures are a regular thing there (and the ice is thinner than usual)?

While temperatures are warm and the ice is thin, it is the migration of ice that will be the key factor. Paradoxically, increased Fram export which is bad for the ice is more likely to push ice up against northern Greenland, preventing an ice free coast from setting up.
Title: Re: The 2018 melting season
Post by: A-Team on May 17, 2018, 06:00:45 PM
The content-rich Jaxa site has the cleverest design of all the Arctic data portals that we use. It is written in Angular.js; the screenshot below shows the available options. The view is 'Bering Strait down', or 135º cw from our usual 'Greenland down' orientation.

https://ads.nipr.ac.jp/vishop/#/monitor

The first mp4 shows the first 135 days of an ambitious triple product: land snow pack thickness, open water sea surface temperature and sea ice concentration. The latter was far too faint in the original and so had to be isolated and contrast-enhanced separately. (To make the land mask, grays from mid-summer low-snow days were combined until the mask was entirely snow free.)

Snow coverage drops precipitously near the end of the time series. Snow-on-land has its own forum as it is only indirectly relevant to sea ice melt season through its loss-driven warming effect on land surface temperature and thus on local air temperature (there being a vast land area in the northern northern hemisphere impacted). Both land snow and sea ice are important reflectors back to space of incoming solar radiation.

The second mp4 shows the first 136 days of Jaxa ice thickness. While this may have some merit, there's no immediate link to methodology and some artifacts of passing weather can be seen.
Title: Re: The 2018 melting season
Post by: VeliAlbertKallio on May 17, 2018, 07:46:33 PM
Another paradoxy is that when overall ice covered part of the ocean is getting smaller, the remaining ice can be more easily redistributed by storms and winds to unusual places. A thin and soft ice can also pack up like harmonica. So we could have all sorts of scenarios as the jet streams have weakened and the winds occasionally push air across the North Pole from the Atlantic to the Pacific. But any such oddities are likelier towards end of season if ice area is small.  8)

I wonder if the ice north of Greenland could melt completely this year (if it is not replaced from somewhere else), since positive temperatures are a regular thing there (and the ice is thinner than usual)?

While temperatures are warm and the ice is thin, it is the migration of ice that will be the key factor. Paradoxically, increased Fram export which is bad for the ice is more likely to push ice up against northern Greenland, preventing an ice free coast from setting up.
Title: Re: The 2018 melting season
Post by: A-Team on May 17, 2018, 08:46:10 PM
Quote
ice cover getting smaller, more easily redistributed by winds to unusual places. A thin and soft ice can also pack up like harmonica. the jet streams have weakened and the winds occasionally push [ice] across the North Pole. soft ice compresses like an accordion.
Right. The relationship between wind strength and ice movement is indirect, mediated primarily by 'form drag' or the frictional coupling between rough surfaces such as compression ridges and floe edges, summing with ocean-ice 'form drag' from keels and bottom skin. Recent papers by P. Lu and A. Petty provide details on the physics there:

https://scholar.google.com/scholar?client=opera&oe=UTF-8&um=1&ie=UTF-8&lr&cites=3522928423510465463

http://alekpetty.com/papers/

It is very difficult to get at those parameters, much less compare them year on year or predict ice movement in advance, so for our purposes it suffices just to look at net ice movement itself. The two main tools for gridded daily displacements are Jaxa and OSI-SAF sea ice drift products.

The first 135 days of 2018 ice motion are compared below. The Jaxa product has wind speed coloring so a static png can give an overview of both storm events and local sites of motion. OSI-SAF shows dodgy ice and derives better vectors from a two-day motion determination. Ascat, up-forum, provides the best summation of these daily motions and the deformations of large-scale trackable features.

The Arctic Ocean ice pack, even in the dead of winter, does not move as a rigid body (restricted to translations and rotations). On the contrary, forcings are very unevenly applied and the resulting motion is regionally distinct: in 2018, quite pronounced off the Alaskan coast, episodic out the Fram, persistent and noteworthy south across the Svalbard-FJL line, westward along the Siberian coast, but with hardly any motion at all (since mid-September!) in the central Arctic. 

As Veli notes above, thermodynamic considerations alone are insufficient for an understanding of melt season and have zero prospects for predicting September minimums or overall timing of ice disappearance.  Passive intra-basin transport of ice to warmer or sunnier locations can play just as important a role as storm fragmentation of floes or conventional out-of-basin export.
Title: Re: The 2018 melting season
Post by: gerontocrat on May 17, 2018, 10:10:48 PM
I know A-team thinks the DMI North of 80 graph is not significant but despite that here it is.
Later than 2017 but is the above average temperature trend coming to a halt?
Title: Re: The 2018 melting season
Post by: Neven on May 17, 2018, 10:22:37 PM
Not if the GFS temperature forecast is correct. Most of the positive anomaly is centred around the Pole:

http://pamola.um.maine.edu/wx_frames/gfs/arc-lea/t2anom/mp4/gfs_arc-lea_t2anom_2018-05-10-12z.mp4
Title: Re: The 2018 melting season
Post by: A-Team on May 17, 2018, 11:21:47 PM
>the DMI North of 80 graph is not significant (?) but despite that

80ºN is kinda Dane-o-centric whereas the 67ºN Chukchi-o-centric is needed too. I was thinking blizzard92 has some way of making contoured mean temperature maps for the whole AO, as well as anomaly relative to post-2010? If that could be done on a rolling monthly (semi-weekly?) basis instead of roman calendar months ... ditto for EMWF 7-day forecast  ... ditto mslp and winds, then we could all go home, the idea being using the anomaly forecast as a multiplicative overlay on concentration to determine coming at-risk areas.

https://twitter.com/ZLabe/media
Title: Re: The 2018 melting season
Post by: Neven on May 18, 2018, 10:40:06 AM
The ECMWF SLP forecast is looking a bit worse again now, with high pressure remaining relatively high and quite extensive. D7-10 has the high pressure moving over to the Siberian side of the Arctic, but forecasts that far out tend to be volatile, and so there's no use in posting them. Here's D1-6:
Title: Re: The 2018 melting season
Post by: A-Team on May 18, 2018, 05:21:00 PM
Here is the last of the Jaxa offerings, PR89 (radar polarization ratio at 89 GHz). The mp4 shows the first 137 days of 2018 as contrast-enhanced UL, daily difference UR, glow contrast-enhanced LL, and sepia daily difference LR.

The artifacts seem just overwhelming -- both weather and furrowing arcs -- and it's never been entirely what PR89 is good for as a standalone tool. However 'PR89 polarization ratio' provides a distinctive google scholar search term, yielding at two rounds the following titles for recent years (and the conclusion use SMOS products):

Estimation of thin ice thickness for coastal polynyas in the Chukchi and Beaufort Seas
Estimation of thin ice thickness from AMSR-E data in the Chukchi Sea
Thin ice detection in the Barents and Kara Seas with AMSR-E and SSMIS radiometer data
Thin sea ice identification in the Kara Sea using AMSR-E data
A modular ridge randomized neural network applied to the estimation of sea ice thickness
An assessment of sea-ice thickness along the Labrador coast from AMSR-E and MODIS
Improvement and sensitivity analysis of thermal thin-ice thickness retrievals
On the accuracy of thin-ice thickness retrieval using MODIS thermal imagery over Arctic FYI
SMOS-derived thin sea ice thickness: algorithm baseline
Estimation of sea ice freeboard from SARAL/AltiKa data
Sea ice production and water mass modification in the eastern Laptev Sea
Observations of supercooled water and frazil ice formation in an Arctic coastal polynya
Lead detection in Arctic sea ice from CryoSat-2: quality assessment
Long-term variation in sea ice production and intermediate water in the Sea of Okhotsk
Global view of sea-ice production in polynyas and its linkage to dense/bottom water formation
Spatio-temporal variability of polynya dynamics and ice production in the Laptev Sea
Near-bottom water warming in the Laptev Sea in response to atmospheric and sea-ice conditions
Origin of freshwater and polynya water in the Arctic Ocean halocline in summer 2007
Helicopter-borne observations with portable microwave radiometer in the Sea of Okhotsk
Sea ice surface temperature estimation using MODIS and AMSR-E data along the Labrador Coast
Impact of Laptev Sea flaw polynyas on the atmospheric boundary layer and ice production
A wind‐driven, hybrid latent and sensible heat coastal polynya off Barrow, Alaska
Changes in distribution of brine waters on the Laptev Sea shelf in 2007
Impact of Siberian coastal polynyas on shelf‐derived Arctic Ocean halocline waters
Variability and trends in Laptev Sea ice outflow between 1992-2011
Title: Re: The 2018 melting season
Post by: Greenbelt on May 18, 2018, 06:45:38 PM
The ECMWF SLP forecast is looking a bit worse again now, with high pressure remaining relatively high and quite extensive. D7-10 has the high pressure moving over to the Siberian side of the Arctic, but forecasts that far out tend to be volatile, and so there's no use in posting them. Here's D1-6:

This morning's GFS has the big central arctic 1030mb dome weakening slightly and sliding toward Canada, with lots of low pressure from Greenland to northwestern Russia. Longer range seems to have strong surface high between Iceland and Scandinavia, and also big high building in far northeastern Siberian arctic coast.

(https://www.tropicaltidbits.com/analysis/models/gfs/2018051812/gfs_z500_mslp_nhem_21.png)
(https://www.tropicaltidbits.com/analysis/models/gfs/2018051812/gfs_z500_mslp_nhem_32.png)
Title: Re: The 2018 melting season
Post by: gerontocrat on May 18, 2018, 07:31:30 PM
Global Ocean Heat Content from NOAA updated for 1st quarter 2018. Not a surprise that the only way is up.
https://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/
Title: Re: The 2018 melting season
Post by: subgeometer on May 20, 2018, 07:09:11 AM
I know A-team thinks the DMI North of 80 graph is not significant but despite that here it is.
Later than 2017 but is the above average temperature trend coming to a halt?

The forecasts (GFS, ECWMF) are showing another lurch upwards about to begin, with very warm air intruding via the Laptev and ESS  especially after midweek. Maybe 0C wiil be reached a few days early this year if the trend continues
Title: Re: The 2018 melting season
Post by: Alexander555 on May 20, 2018, 11:27:05 AM
https://robertscribbler.com/2018/05/20/potential-historic-arctic-warming-scenario-in-the-gfs-model-forecast-for-late-may/
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 20, 2018, 04:30:58 PM
Global Ocean Heat Content from NOAA updated for 1st quarter 2018. Not a surprise that the only way is up.
https://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/

Curious about the different slopes of the curve for 0-700 m and 0-2000 m. Does the more rapid warming of 0-2000 m suggest an efficient heat transfer or mixing to depth?
Title: Re: The 2018 melting season
Post by: FishOutofWater on May 20, 2018, 06:04:01 PM
Multiple things are going on in the depths of the ocean that explain the 2000m heat content increase. The subtropical gyres have expanded polewards in both hemispheres. Even a small northwards displacement of the north wall of the Gulf Stream involves massive amounts of heat. There's a still a thermal gradient below 700m depth.

The coldest water in the oceans, Antarctic bottom water is not forming like it used to. The Weddell sea polynya hasn't been active for decades. As less bottom water forms in both hemispheres the oceans warm in the deepest levels as the volume of the ocean's coldest water decreases with time.

In addition, new bottom water is warmer than old AABW.
Title: Re: The 2018 melting season
Post by: bbr2314 on May 20, 2018, 06:33:36 PM
I would think Barentz' imminent total melt-out is going to create a bit of a mini-cliff for area/extent #s. It has been absolutely battered by incoming heat thanks to Scandinavia's melt prior to Siberia / Alaska/ Quebec (at least I suspect this has something to do with it). Without snowpack to modify incoming airmasses, the torch has been sustained and worsening, and this should only continue.

ATL SSTs are running incredibly warm along the northern edge of the Gulf Stream, and there is plenty of heat content available for transport broiling up off the US Eastern Seaboard.

In any case, Barentz' #s are currently being held up by a slush of .25-.5M ice that is not going to resist the next two weeks (IMO). With the actual front E of Greenland already extremely far north, the entire front may take on a rather odd appearance come 6/1-6/15 as Kara holds on, while the main advancing melt front begins taking out chunks of the actual CAB.

HYCOM also shows Hudson Bay's NW edge giving out, and satellite seems to somewhat confirm this, but I don't think things will progress rapidly there as the ice is thick and largely still snow-covered. Both Hudson and Kara may prove resilient this summer vs. normals (but will still melt out entirely by August at the latest). Maybe we see a particularly potent end-of-season drop as well?
Title: Re: The 2018 melting season
Post by: Alexander555 on May 20, 2018, 07:28:42 PM
Is the Ice in Hudson Bay so thick ? If you look on the picture from Nasa Worldview, in the middle it looks brite white. But the west side has a different colour. A little bluish. Or is it a light effect.

And does somebody knows, if you take the area of Hudson Bay. Places like the Hudson Strait and Fox Basin. Are they included in the Hudson Bay area.
Title: Re: The 2018 melting season
Post by: oren on May 20, 2018, 07:45:55 PM
And does somebody knows, if you take the area of Hudson Bay. Places like the Hudson Strait and Fox Basin. Are they included in the Hudson Bay area.
AFAIK these locations are indeed included in Hudson Bay data.
Title: Re: The 2018 melting season
Post by: bbr2314 on May 20, 2018, 08:32:00 PM
Is the Ice in Hudson Bay so thick ? If you look on the picture from Nasa Worldview, in the middle it looks brite white. But the west side has a different colour. A little bluish. Or is it a light effect.

And does somebody knows, if you take the area of Hudson Bay. Places like the Hudson Strait and Fox Basin. Are they included in the Hudson Bay area.
I believe it is quite thick and Canucks confirm.

http://iceweb1.cis.ec.gc.ca/Prod/page3.xhtml

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fice-glaces.ec.gc.ca%2Fprods%2FWIS54SD%2F20180514180000_WIS54SD_0010033188.gif&hash=291c8b6bcb969f7453320fc20b77df89)

The west side is definitely beginning to show some melt but most elsewhere is holding firm. This will begin to change over the next 30 days, of course.

It should also be noted that the above chart includes a handy 7-day mean normal vs. actual temp guide on the lower-left for adjacent Canuck weather stations. All are handily or exceedingly below normal, at least in the week preceding 5/14.
Title: Re: The 2018 melting season
Post by: bbr2314 on May 20, 2018, 08:42:41 PM
Here is 2017 vs 2018 (2018 is... extremely... brighter/whiter)

(https://media.giphy.com/media/bLmeasOQjR2HhOi8OZ/giphy.gif)
Title: Re: The 2018 melting season
Post by: A-Team on May 20, 2018, 11:13:48 PM
UB SMOS consistently indicates thin ice (≤0.5m) only in the northwest corner of Hudson Bay for the last three months. UH SMOS seems to have knocked off for the year on April 15th.

The slideshow compares (1) the overall locations of NH thin ice on 19 May 2018 with the (2) locations given by averaging SMOS colors over the last 80 days (which goes off-key because of faulty UB palette construction) and (3) locations of thin ice colored by their most recent status.

Technical note: the last slide is made by deleting ice >0.5m thick to transparency, then stacking with most recent date on top, then capturing the colors that show through.


The three approaches converge on the usual suspect expected areas of early Arctic Ocean melt, SW Beaufort, SE Chukchi, Laptev periphery, Kara and Svalbard-FJL-N Barents.

Jaxa 36V,36H,18V provides a more nuanced view of Hudson Bay, starting to capture ice of a different (dodgier) status in the southwest and south over the last couple of weeks.

UH AMSR2 confirms this at 3.125 km resolution after discounting non-persistent effects of passing weather.
Title: Re: The 2018 melting season
Post by: meddoc on May 21, 2018, 10:18:19 AM
Someone already mentioned the Hot Blob developing in the North Atlantic. Although the Cold Areas have also expanded quite a bit (mind You these are just Sea Surface Temp Anomalies- up to 2 m Depth, if I'm correct).
This will certainly churn out some Storms heading into the Arctic, the Question is 1) how and 2) when will it affect direct Heat Transport through the Gulf up to Svalbard & Arctic.
Title: Re: The 2018 melting season
Post by: Gray-Wolf on May 21, 2018, 11:33:30 AM
Just the lack of sunshine on the waters below (for the areas under constant low pressure formation) will keep the sst's suppressed. It might look dramatic ,esp. hard up against positive anoms, but it would disappear very quickly once 'normal services' are resumed.

The growth of the positive anoms are different as we know hurricanes feed of the ocean below so any little help in their formation will lead them to bomb into big storms. The storms will trawl up waters from deeper down but we appear to have built quite a reserve of warmth in the tropical Atlantic?

Why is this important? Well we all know where the storms end up! Be it Baffin or Fram we could see plenty of energy headed north in late Aug/early Sept.

Never mind what happens in the Arctic doesn't stay in the Arctic.... what happens outside the Arctic WILL impact the Arctic!
Title: Re: The 2018 melting season
Post by: JayW on May 21, 2018, 12:03:52 PM
Pacific side, 105 hours, May 16-20.  I went with an mp4 to preserve detail.  Low clouds are clearing out as a "cleaner" high pressure appears to be taking over.  If the ECMWF is to be believed, it will have some staying power.

"Little darling, it's been a long cold lonely winter
Little darling, it feels like years since it's been here
Here comes the sun, here comes the sun
And I say it's all right…"

  - George Harrison


http://feeder.gina.alaska.edu/npp-gina-alaska-landcover-images?search%5Bfeeds%5D%5B6%5D=1&search%5Bsensors%5D%5B3%5D=1
Title: Re: The 2018 melting season
Post by: bbr2314 on May 21, 2018, 04:38:15 PM
It seems like the lack of Greenland Sea ice this year coupled with the warmth in the very far NATL has sufficed to produce a ridiculous vortex. Record-setting?

Wonder how long it persists into the season / maybe it is a "new thing" of the ridiculous SST / snowfall distribution across the ATL and its peripheral continents?

In any case, I would suggest that the presence of ^ indicates that the high Arctic is going to lose its "guts" of the cryosphere increasingly often this summer as the main cold pole co-locates to the periphery of wherever ^ vortex resides.

It should also be noted that models are setting up an absolute torch over far northern Europe / Scandinavia in the extended...
Title: Re: The 2018 melting season
Post by: A-Team on May 21, 2018, 06:12:43 PM
Below is a cloud-free Modis mosaic of the Arctic from May 6-14 images put together by the Canadian Ice Service. It extends down to approximately 55ºN and so picks up most of the remaining NH high albedo snow and ice of the planet's declining refrigerator.

https://pbs.twimg.com/media/DdX63EsVQAEBdtZ.jpg:large (needs 60º cw rotation)

It's shown slightly cropped with contrast adjustments below, along with the same view from Ascat and Jaxa, both from May 20th.
Title: Re: The 2018 melting season
Post by: bbr2314 on May 21, 2018, 06:23:59 PM
I think the ^ images show something interesting / possibly confirm a differential in 2018 vs. the major melts of yesteryear like 2012.

2011 and especially 2012 were driven by early melt-outs of continental snowpack in conjunction with some oceanic warming. But the early melt of continental snowpack was critical, especially across North America in 2012, in allowing airmass-driven melting to begin across the Arctic far earlier than normal.

2018 is very different from these years. Our numbers are lower, but the continental situation this spring has been a literal climate away from 2011 / 2012. Forgetting comparisons versus "normal", volume of SWE and snow extent were both *massively* above 2011 and 2012. But Arctic sea ice was even lower than both of those years!

I think this has important implications as we head deeper into the melt season because the way melt is now progressing is changing. We are now seeing some muting of airmass-driven melt (at least prior to solstice, this is likely to change as continental snows melt out by July). But melt driven by increasing oceanic heat has MORE than made up for this deficit. And, surprisingly to some, this has been most apparent in areas of the pack that are very close to 90N -- namely, both the Bering, and the high ATL seas (Barents/Greenland).

The GFS et al have been far too aggressive in their depicted warmings over the Arctic in recent weeks and I think this is because snowpack has been surprisingly resistant to melt (again, this will change). But perhaps the trend so far this spring and the comparison / contrast vs. 2011 / 2012 indicate that we are likely to see much more cyclonic activity this fall, in keeping with the ever-increasing oceanic heat content? The contrast with relatively cooler continental airmasses vs the other years could mean that the gradient is even worse in 2018 / cyclones are stronger.
Title: Re: The 2018 melting season
Post by: A-Team on May 21, 2018, 06:24:04 PM
What online archive should we use this spring for near-real time melt ponds? So many papers but no daily archive? Looking in the rear view mirror provides little of value during times of rapid change:

Revisiting the potential of melt pond fraction as predictor for seasonal Arctic sea ice extent minimum
Jiping Liu et al 19 May 2015
http://iopscience.iop.org/article/10.1088/1748-9326/10/5/054017/meta

A recent modeling study [Schroder 2014] that employed a prognostic melt pond model in a stand-alone sea ice model found that September Arctic sea ice extent can be accurately predicted from the melt pond fraction in May. Here we show that satellite observations show no evidence of predictive skill in May. However, we find that a significantly strong relationship (high predictability) first emerges as the melt pond fraction is integrated from early May to late June, with a persistent strong relationship only occurring after late July.

Melt pond fraction is derived from MODIS surface reflectance as processed by a neural network using spectral characteristics of melt ponds relative to open water, snow and ice. The melt pond fraction is available at 8 day interval from 9 May to 6 September with a spatial resolution of 12.5 km from 2000 to 2011 [Rösel et al 2012].

The observed climatological melt pond fraction is ~11% in early May and increases rapidly in late May and June (~23% in late June and reaching a peak ~25% in early July), followed by a gradual decrease (still retaining ~20% in late August and early September) as shown in Fig1a.

This archive is based on Modis but has no data beyond Sept 2011:
  https://icdc.cen.uni-hamburg.de/1/daten/cryosphere/arctic-meltponds.html
  ftp://ftp-icdc.cen.uni-hamburg.de/arctic_meltponds/

The impact of melt ponds on microwave brightness temperatures and sea-ice concentrations
S Kern et al Sept 2016
https://www.the-cryosphere.net/10/2217/2016/tc-10-2217-2016.pdf

Sea-ice concentrations derived from satellite microwave brightness temperatures are less accurate during summer. In the Arctic Ocean the lack of accuracy is primarily caused by melt ponds, but also by changes in the properties of snow and the sea-ice surface itself. We investigate the sensitivity of eight sea-ice concentration retrieval algorithms to melt ponds by comparing sea-ice concentration with the melt-pond fraction.

One potential reason for the reduced accuracy is the change in microphysical properties inside the sea ice, for instance, the desalination of the sea ice during the melt process or the flushing of air voids in multiyear ice with meltwater and other melt processes (Scharien 2010).

The three key surface features of summer melt on Arctic sea ice are a metamorphou wet snow cover, a porous, wet sea-ice surface, and melt ponds. During summer, the snow cover on sea ice is usually wet or even saturated with meltwater. Its density is usually considerably larger during summer than during winter.

Diurnal melt–refreeze cycles,  episodes of intermittent melting and refreezing of the snow, which is a common phenomenon during late spring, result in an increase in the snow grain size. Wet snow is an efficient absorber of microwave radiation and has a microwave emissivity close to 1. It can effectively block microwave emission from underneath.

Satellite microwave sensors which have been used for sea-ice concentration retrieval allow for footprint sizes between 5 and 70 km. Melt ponds, cracks, and leads are therefore sub-footprint size surface features, and cannot be resolved individually. A satellite brightness temperature measurement of a mixed scene is therefore composed of contributions from the open water, i.e., cracks, leads, melt ponds, and from the (snow covered) sea ice.

This has two main consequences for a sea-ice concentration product computed from such coarse-resolution satellite measurements. The sea-ice concentration in the presence of melt ponds is likely to be underestimated   because melt ponds are seen as open water. Whether the footprint contains, for example, (case A) 100 % sea ice with 40 % melt ponds or (case B) 60% sea ice with 40 % open water from leads and openings, is ambiguous. In both cases, satellite microwave radiometry retrieves 60 % sea-ice concentration because the net sea-ice surface fraction of sea ice in the grid cells is 60 %   

Melt pond fraction and spectral sea ice albedo retrieval from MERIS data
L Istomina et al
The Cryosphere, 9, 1551–1566, doi:10.5194/tc-9-1551-2015, 2015a.
The Cryosphere, 9, 1567– 1578, doi:10.5194/tc-9-1567-2015, 2015b.

The data used for the present study are the pond fraction and broadband sea ice albedo swath data products retrieved from MERIS (Medium Resolution Imaging Spectrometer) swath Level 1b data over the ice-covered Arctic Ocean using the MPD retrieval. The present chapter presents a short summary of the MPD retrieval. T

The full description of the algorithm can be found in EP Zege et al
https://epic.awi.de/38709/1/1-s20-S003442571500108X-main.pdf

"The input to the current version of the MPD algorithm is the MERIS Level 1B data, including the radiance coefficients at ten wavelengths and the solar and observation angles (zenith and azimuth). Also, specific parameters describing surface and atmospheric state can be set in a configuration input file. The software output is the map of the melt ponds area fraction and the spectral albedo of sea-ice in HDF5 format. Currently, the MPD code is arranged as a Linux console application and works in the MERIS processing chain in theUniversity of Bremen, providing a comprehensive melt pond data product based on the complete MERIS data set 2002–2012

Signature of Arctic first-year ice melt pond fraction in X-band SAR imagery
AF Fors et al March 2017
The Cryosphere 11(2) DOI 10.5194/tc-11-755-2017
 
Melt pond fractions retrieved from a helicopter-borne camera system were compared to polarimetric features extracted from four dual-polarimetric X-band SAR scenes, revealing significant relationships. The correlations were strongly dependent on wind speed and SAR incidence angle. Co-polarization ratio was found to be the most promising SAR feature for melt pond fraction estimation at intermediate wind speeds.

A spectral mixture analysis approach to quantify Arctic first-year sea ice melt pond fraction using QuickBird and MODIS reflectance data
JJ Yackel et al Sept 2017 DOI10.1016/j.rse.2017.09.030

Despite its requirement for thermodynamic sea ice modeling,measurement of melt pond areal coverage using satellite remote sensing has proven difficult due to significantspatiotemporal variability in the timing and evolution of melt ponds. Less than optimal results from prior studiesemploying a spectral mixture analysis (SMA) towards the determination of melt pond areal coverage from sa-tellite remote sensing data provided the incentive for a multiple endmember spectral mixture analysis (MESMA)approach. The MESMA was performed on Moderate Resolution Imaging Spectroradiometer (MODIS) imageryusing endmember spectra obtained from atmospherically corrected coincident high resolution imagery, surfaceobservations and modeling. Results were validated against a high resolution Quickbird image acquired coin-cident to the MODIS image.

Melt ponds over Arctic sea ice
D Flocco March 2017
http://blogs.reading.ac.uk/weather-and-climate-at-reading/2017/melt-ponds-over-arctic-sea-ice/

Where ponds form, the ice beneath becomes thinner due to increased melting. Towards the end of the summer, the air temperature drops and a thin layer of ice forms over melt ponds. The ponds’ melt water trapped in the ice acts as a heat store and does not allow the underlying ice to start thickening until all the pond’s water is frozen. Ponds are up to 1.5 m deep and it can take over two months to freeze their volume of water.
Title: Re: The 2018 melting season
Post by: Neven on May 22, 2018, 12:26:34 AM
High pressure has been reduced, but refuses to leave the CAB/Beaufort. With a low pressure over the Laptev, a small dipole is setting up with isobars pointing to winds blowing the ice away from the Siberian coast (but towards the CAA). Here's the ECMWF forecast for the coming six days, I've added a couple of white arrows to show how the winds will blow.

Let's see how much movement there is. I had expected more open water in the Beaufort Sea by now, but maybe the winds have been blowing too laterally to the coast.
Title: Re: The 2018 melting season
Post by: magnamentis on May 22, 2018, 01:08:06 AM
since we don't have so many cameras showing good images of the ice surfaces i thought to post this one in barrows that IMO shows melt-ponding at a temperature of -3C.

somehow it can be assumed that would look similar in other places and especially where temps are at or slightly above freezing point.

since i'm not an ice-man this assumption could be an error, gladly learning if so, just share your take on the subject ;)
Title: Re: The 2018 melting season
Post by: uniquorn on May 22, 2018, 01:13:09 AM
A comparison of may2017 to may2018 using ascat. There are many similarities in the ice movement so far.
2017(left) shows the lift off of MYI from the CAA ready to start it's way around the coast of the Beaufort Sea. It looks like the same movement will continue this year and that string of MYI is already exposed to open water in the Chukchi.

On the Atlantic side the area north of Svalbard has opened up significantly during May this year, the younger (darker) ice of the 'Kara tongue' perhaps struggling against southerly winds and warmer water. It will be interesting to see what happens if it meets the area north of Greenland where the weaker ice from the February storm still shows. Overall there is now less extent in the Barents than last year.
Nares strait was already open for export in 2017 and it didn't close until March 2018 (I think). That long year of MYI export leaving thinner ice still visible in the Lincoln sea.

tech notes
imagej: brightness/contrast 41,255 clahe 63,256,2.2
Title: Re: The 2018 melting season
Post by: Michael Hauber on May 22, 2018, 02:28:30 AM
since we don't have so many cameras showing good images of the ice surfaces i thought to post this one in barrows that IMO shows melt-ponding at a temperature of -3C.

somehow it can be assumed that would look similar in other places and especially where temps are at or slightly above freezing point.

since i'm not an ice-man this assumption could be an error, gladly learning if so, just share your take on the subject ;)

Looks to me like the melt ponds are close to the coast - perhaps the impact of nearby landmass absorbing a lot more solar heat.  The horizon looks much brighter and whiter.
Title: Re: The 2018 melting season
Post by: Michael Hauber on May 22, 2018, 02:36:35 AM
High pressure has been reduced, but refuses to leave the CAB/Beaufort. With a low pressure over the Laptev, a small dipole is setting up with isobars pointing to winds blowing the ice away from the Siberian coast (but towards the CAA). Here's the ECMWF forecast for the coming six days, I've added a couple of white arrows to show how the winds will blow.

Let's see how much movement there is. I had expected more open water in the Beaufort Sea by now, but maybe the winds have been blowing too laterally to the coast.

And enough heat for some substantial surface melting in Siberian and Laptev regions. 
Title: Re: The 2018 melting season
Post by: jdallen on May 22, 2018, 02:38:46 AM
since we don't have so many cameras showing good images of the ice surfaces i thought to post this one in barrows that IMO shows melt-ponding at a temperature of -3C.

somehow it can be assumed that would look similar in other places and especially where temps are at or slightly above freezing point.

since i'm not an ice-man this assumption could be an error, gladly learning if so, just share your take on the subject ;)

Looks to me like the melt ponds are close to the coast - perhaps the impact of nearby landmass absorbing a lot more solar heat.  The horizon looks much brighter and whiter.
Blown dust effect?
Title: Re: The 2018 melting season
Post by: jdallen on May 22, 2018, 02:42:03 AM
High pressure has been reduced, but refuses to leave the CAB/Beaufort. With a low pressure over the Laptev, a small dipole is setting up with isobars pointing to winds blowing the ice away from the Siberian coast (but towards the CAA). Here's the ECMWF forecast for the coming six days, I've added a couple of white arrows to show how the winds will blow.

Let's see how much movement there is. I had expected more open water in the Beaufort Sea by now, but maybe the winds have been blowing too laterally to the coast.
I'd say we watch the Barentz closely as well.  Wind and wave action from those two lows may have a pronounced affect the already weak ice between FJL and Nova Zemlya.
Title: Re: The 2018 melting season
Post by: NACK on May 22, 2018, 10:18:42 AM
Whoa!

Has GFS "thrown a rod"?

On May 30th, it is indicating the west shore of Hudson Bay will approach 100 degrees and I'm talking DegF, not DegK :)

If the prediction turns out to be accurate, the white bears need to find another source of subsistence for sure.

How many 100 degree days will it take to melt the SI in the Bay?

P.S. I'm thinking about buying some land on Baffin Island and start growing potatoes.

Title: Re: The 2018 melting season
Post by: Trebuchet on May 22, 2018, 02:53:40 PM
since we don't have so many cameras showing good images of the ice surfaces i thought to post this one in barrows that IMO shows melt-ponding at a temperature of -3C.

somehow it can be assumed that would look similar in other places and especially where temps are at or slightly above freezing point.

since i'm not an ice-man this assumption could be an error, gladly learning if so, just share your take on the subject ;)

 The ice along pretty much the entire north coast of Alaska looks suspiciously blue on Worldview today.
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 22, 2018, 03:21:04 PM
uniquorn....

The Atlantic side of the Arctic looks particularly vulnerable when compared to last year. A lot of thin FYI. My guess is we will end up with more open water on this side of the CAB than ever before. Normally, we would expect ice moving towards the Fram to replenish this area but SST are extraordinarily high with open water north of Svalbard throughout the winter.
Title: Re: The 2018 melting season
Post by: VeliAlbertKallio on May 22, 2018, 04:14:11 PM
If the Atlantic front retreated sufficiently during the course of summer, there is a possibility that the remainder of ice would be out of reach of the transpolar drift. It could even happen that CAB ice gets pushed into the Beaufort Gyre, either way, ice gets more in contact with sun. That is, of course, an outlier possibility but the situation has also changed dramatically from the past.

uniquorn....

The Atlantic side of the Arctic looks particularly vulnerable when compared to last year. A lot of thin FYI. My guess is we will end up with more open water on this side of the CAB than ever before. Normally, we would expect ice moving towards the Fram to replenish this area but SST are extraordinarily high with open water north of Svalbard throughout the winter.
Title: Re: The 2018 melting season
Post by: uniquorn on May 22, 2018, 04:21:34 PM
Thursday's ecmwf wam(wave) forecast from windy certainly won't help.
edit: Looks pretty rough near the Kane Basin arch too

Quite a few red areas on the pacific side using Worldview terra/modis bands 3,6,7. I'm no expert at spotting melt ponds though.
Title: Re: The 2018 melting season
Post by: A-Team on May 22, 2018, 10:20:32 PM
>out of reach of transpolar drift

There has been no transpolar drift whatsoever in 2017-18 and none is in the works.
Title: Re: The 2018 melting season
Post by: slow wing on May 23, 2018, 02:25:21 AM
Thanks A-team!

Your .mp4 "233 days of anti-transpolar drift 2017-2018" is probably going to become my go-to reference for where last year's remaining ice has drifted since.

I downloaded the movie and by dragging the cursor backwards & forwards through the time sequence can easily track features visually to see how the different parts of the ice pack have moved. Much appreciated!  :)
Title: Re: The 2018 melting season
Post by: slow wing on May 23, 2018, 03:07:25 AM
For the multi-year ice I tend to conceptualize the drift pattern - both this past year & previous several years - slightly differently from the canonical description of a Beaufort gyre +trans-polar drift (agree, the latter not much seen if at all these years).

Instead, I see it as a prevalent drift from the (central) Russian side to the (central) Canadian side that compresses the ice against the Canadian Arctic coastline but also with faster drifts on both the Atlantic & Alaskan sides - the former in a similar direction but the latter bringing the ice back in the opposite direction, towards Russia.

The fast Atlantic side drift sweeps that ice through the Fram Strait, unless it melts out first. This is in pretty much in the same direction as the prevalent central drift only faster because the ice isn't blocked.

The drift on the Alaskan side sweeps the ice fast in the opposite direction to the central & Atlantic-side drifts, in a direction parallel to the Alaskan Arctic coastline & in the direction of Russia.

The sum of the central+Alaskan-side drifts is re-describing the Beaufort gyre, obviously, but acknowledges that the drift back towards Russia is seen to be much faster because it isn't blocked by land, namely the Canadian Arctic coastline. (There is a small leak through the Nares Strait though.)


Is this a useful way now to broadly conceptualize the Arctic sea ice movement given that there is no longer significant a) trans-polar drift, or b) sea ice that survives multi-year cycles around the Beaufort gyre?
Title: Re: The 2018 melting season
Post by: uniquorn on May 23, 2018, 11:47:03 AM
I would add another arrow from the Kara Sea into the CAB. The volume depends on how quickly Kara melts out.

With a week of warmer winds forecast for the Laptev Sea, here is Worldview terra/modis may15-23. The next few days should give more indication of any anomalously thicker areas.
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 23, 2018, 02:20:15 PM
Unless I don't understand how to interpret this Arctic ice image, it seems the Laptev Sea has a lot of vulnerable 1st year ice that extends well into the CAB along Severnaya Zemlya.

Something to watch?
Title: Re: The 2018 melting season
Post by: numerobis on May 23, 2018, 04:03:34 PM
NACK: the GFS forecast shows pretty similar temperatures near the sea as ECMWF; the difference is about 100 km inland in Ontario and Manitoba.

I have a potato plant growing on Baffin Island right now. It could be a bit happier -- it hasn't been very sunny this month. I expect my May heating bill to be on par with April's despite the rather warmer temperatures.
Title: Re: The 2018 melting season
Post by: A-Team on May 23, 2018, 04:49:52 PM
Right, ice motion is highly non-uniform and difficult even to describe because of feature distortion over time, with overall mobility hard to compare year on year. ECMWF --> MSLP --> wind --| ice motion because form drag is highly variable and largely unknown.

It is a very poor idea to use averaged gridded ice velocity vectors because of uncorrelated commutativity cancellation issues discussed at length up-forum yet you will see this all over, for example on the WHOI buoy home page.

The six years available for Ascat on May 22nd are shown below. This year, on this date, looks most like 2016. We have not seen the sharp elbow before in the Chukchi of the Beaufort stringer of CAA thick coastal ice. This resulted from strong persistent westward zonal (latitudinal) winds along the Alaskan coast, combined with southeast Chukchi lift-off and surge from the Bering Sea.

Quote
Laptev ice along SZ is FYI, to melt out
Right. Basically all the darker ice on Ascat is FYI which will melt out by September, including the non-peripheral components. Add to this the brighter ice that has been transported to warmer seas and you have a rough prediction for the fall. The 'union jack' coloration of Ascat portrays that fairly well.
Title: Re: The 2018 melting season
Post by: A-Team on May 23, 2018, 06:36:09 PM
Here is a first pass at ice classification based on its provenance (origin history) implied by the 233 day time series a couple posts back. Modulo subsequent translocation and plastic deformation, this provides a rough prediction of what ice will remain where in mid-September.

The two Ascat-based posterization slides give a more nuanced version under the assumptions that Ascat roughness ~ ice age ~ ice thickness ~ location coldness ~ susceptibility to melt. That has worked out fairly well for recent years, though the Great Arctic Cyclone of early August 2012 is missing from the Ascat archive available.

Jaxa images come from a very different instrument but its posterization-prediction is not dissimilar from Ascat. It has more potential for melt pond tracking (pinkish regions) but weather artifacts bring in considerable ambiguity.
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 23, 2018, 09:29:24 PM
Fantastic images! Thanks.
Title: Re: The 2018 melting season
Post by: Lord M Vader on May 24, 2018, 09:06:04 AM
Seems like the ESS has started to melt. How unusual is that at this time of year compared to other years?

In the southern part of Chukchi and northern Berings Sea the SSTs are already at a full degree above zero. Imagine how warm those areas might be when refreezing season starts?  :o
Title: Re: The 2018 melting season
Post by: subgeometer on May 24, 2018, 10:12:38 AM
Wafer Thin refreeze ice north of the Lena delta in the Laptev can't hold out long against current heat influx.. I also made a little gif showing the boundary of the fast ice against a bathymetry map (from the Laptev wiki page) I roughly stretched to match projections
Title: Re: The 2018 melting season
Post by: Gary H on May 24, 2018, 08:41:45 PM
Will the rather flat trend for the Sept min sea ice extent of the last decade, continue in 2018?
Title: Re: The 2018 melting season
Post by: numerobis on May 24, 2018, 09:24:46 PM
There's been no statistically significant global warming since last July, so probably.
Title: Re: The 2018 melting season
Post by: Stephan on May 24, 2018, 09:26:36 PM
As data exist from 1979 on it isn't really wise to use only ten years of ice trends (not for winter maxima or September minima or any other time of the year). As every year is different, and external influence from temperature, waves, cloudiness, water temp. etc. mainly determine the individual year's pattern and melting, a period of only ten years does not give a representative trend line. This short period can only "summarize" the annual variability which maybe leads to a trend line that differs from the long-term climatological trend.
AGW deniers sometimes do "cherry picking" on even a fewer number of years to show the trend they want the public to see.
Title: Re: The 2018 melting season
Post by: Greenbelt on May 24, 2018, 09:40:40 PM
In fact there's a longer time frame graphic linked on this very site!
https://sites.google.com/site/arcticseaicegraphs/longterm
(https://sites.google.com/site/arcticseaicegraphs/_/rsrc/1517001388768/longterm/2017_sea_ice_PIOMAS.png?height=290&width=400)
Title: Re: The 2018 melting season
Post by: Gary H on May 24, 2018, 09:49:28 PM
Beginning the analysis in 1979 is cherry picking. Why did we stop discussing the decades long increasing trend - leading up to 1979 - in Arctic sea ice extent? Noting that there's been a flat trend here for a decade is simply interesting in the moment. Does it perhaps suggest that we could be ending one cycle and beginning another? Also interesting that the Arctic sea ice volume is rather interesting in the moment.  http://ocean.dmi.dk/arctic/icethickness/thk.uk.php

One can toggle back - I just put May 23, 2008 side by side with yesterday's ice thickness - interesting.

 Graph was in the 1990 IPCC report. 
Title: Re: The 2018 melting season
Post by: numerobis on May 24, 2018, 10:32:27 PM
Hard to read that photocopy of a 28-year-old document but the scale shows the variability is fully contained in +/- 1 million km^2. So that would put the lowest point on that scale bar (which is below any data point) as being about 5.8 Mkm^2. The minimum was last that high in 2004.

Sorry, did you have a point?
Title: Re: The 2018 melting season
Post by: Hyperion on May 24, 2018, 10:47:48 PM
Beginning the analysis in 1979 is cherry picking. Why did we stop discussing the decades long increasing trend - leading up to 1979 - in Arctic sea ice extent? Noting that there's been a flat trend here for a decade is simply interesting in the moment. Does it perhaps suggest that we could be ending one cycle and beginning another? Also interesting that the Arctic sea ice volume is rather interesting in the moment.  http://ocean.dmi.dk/arctic/icethickness/thk.uk.php

One can toggle back - I just put May 23, 2008 side by side with yesterday's ice thickness - interesting.

No gary. The flat ten year extent minima curve is the result of an increasingly mobile, fragmented, porous and fragile pack sprawling outwards as it is pummeled by increasingly vigorous weather systems. Composed increasingly of porous spongy ice with layers of frozen surface melt interspersed with snow reducing its density, therefore showing more freeboard to satellite sensors. Also wave slosh and wicking drawing salinity upward into the surface layercake.  These factors are making the modeled thickness and volume figures we are being fed overstate the MASS of frozen H2O in the Arctic ocean, as this process is moving much faster than the science burocracy can move to update the modelling algorithms. Particularly as funding and feasibility of boots on the ice direct measurement to calibrate the models has crashed. In no small part due to big business and political corruption, not to mention it now being near impossible to find floes firm or stable enough to land a plane on or camp on.  ::)
Title: Re: The 2018 melting season
Post by: Aluminium on May 24, 2018, 11:22:11 PM
The flat ten year extent minima curve is the result of an increasingly mobile, fragmented, porous and fragile pack sprawling outwards as it is pummeled by increasingly vigorous weather systems.
The horizontal ten-years trend has no statistically significant difference with the decreasing forty-years trend. Appearance of short horizontal trends can be explained by random fluctuations.
Title: Re: The 2018 melting season
Post by: Archimid on May 24, 2018, 11:31:13 PM
Gary H. First this discussion is off-topic in the Melting Season thread. I suggest we continue this discussion here:

https://forum.arctic-sea-ice.net/index.php/topic,224.0.html


There we have early satellite images of the period you describe as "decades long increasing trend".

However your true lies on this thread must be refuted, risking the ire of the ASIF gods.

Quote
Beginning the analysis in 1979 is cherry picking.

How is taking the whole sattellite data set cherry picking?

Quote
Why did we stop discussing the decades long increasing trend - leading up to 1979 - in Arctic sea ice extent?

What decades long increasing trend?

(https://upload.wikimedia.org/wikipedia/commons/d/da/Arctic_Sea_Ice_Extent_Anomaly_1953-2007.png)

Quote
Noting that there's been a flat trend here for a decade is simply interesting in the moment. . Does it perhaps suggest that we could be ending one cycle and beginning another?

Surely there has been a hiatus in extent drop and a shorter hiatus in volume loss. The question is how long it will last and what happens next. Given Arctic temperatures I have no clue why you think the the next step change will be up. The next step will be down and may be the last one.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fberkeleyearth.org%2Fwp-content%2Fuploads%2F2018%2F01%2FArctic2017.png&hash=9a6d7f98c986c59740f98244cf5ee50e)

Quote
Also interesting that the Arctic sea ice volume is rather interesting in the moment.

Interesting? I would call it scary compared to the volume of the 20th century. 

Quote
Graph was in the 1990 IPCC report.

Nice cherry. This cherry is typically associated with climate change deceivers. It seems to me like an averaged annual sea ice extent, for a very narrow set of years. I have to imagine the very slight increase at the beginning is due to larger growth of sea ice in the winter averaged with September losses.
Title: Re: The 2018 melting season
Post by: Daniel B. on May 24, 2018, 11:31:40 PM
The flat ten year extent minima curve is the result of an increasingly mobile, fragmented, porous and fragile pack sprawling outwards as it is pummeled by increasingly vigorous weather systems.
The horizontal ten-years trend has no statistically significant difference with the decreasing forty-years trend. Appearance of short horizontal trends can be explained by random fluctuations.
Neither does the 18-year horizontal trend at the start of the dataset.  The reason there is no statistical difference is due to large inter annual variations.  Almost all the ice loss occurred over a 12-year period from 1996-2007. 
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 24, 2018, 11:33:11 PM
Beginning the analysis in 1979 is cherry picking....

What does this have to do with this melting season?
Title: Re: The 2018 melting season
Post by: A-Team on May 24, 2018, 11:37:25 PM
Back on melt season, a nice contribution from subgeo at #780 in the Laptev region of seasonal landfast ice and its frequent flaw polynyas (which have been studied for decades). The proximal cause is wind-driven shift of the ice pack, with not all of it going along.

The question concerns the relatively consistent position of the break-line -- is it ice thickness, local bathymetry, ice shelf breaks, tidal fluxes, river-lowered salinity, ice reformation-driven haloclines or what.

The first order of business is just pulling together data in terms of time series and overlays. The imagery below supplements Modis ice, land edge and bathymetry that subgeo provided with Jaxa RGB radar, literature review diagrams, Osi-Saf two day wind since March, open water AMSR2 and intermediate ice.

This feature (and a similar one next door on the Kara) are not entirely of academic interest but neither are they pivotal to melt season records and the like.

Technical note: the animation in #780 doesn't play initially because its height of 760 pixels exceeds forum limits. Modis ice images use very little of color space and benefit from contrast tightening.
Title: Re: The 2018 melting season
Post by: Chuck Yokota on May 24, 2018, 11:45:00 PM
Beginning the data series in 1979 is in no way cherry picking. It was in fact the first year that satellites made possible the direct observation of the entire Arctic ocean on a daily basis. Prior to that time, data was spotty at best, with vast stretches of the Arctic going unobserved for weeks or months at a time. Prior to 1979, the Arctic sea ice extent numbers were only estimates and extrapolations from sparse observations.

In the decades since 1979, research has endeavored to get a better picture of the Arctic sea ice extent from earlier times. More than a one and a half centuries of whaling ships' logs of the edge of the ice pack, compilation of observations of Arctic expeditions, and proxy information such as examination of sea floor sediments have provided a better picture of the sea ice extent in earlier decades.

They show that the sea ice extent has consistently been larger than the current time, with much more older and thicker sea ice. There is no trace of a 40 year cycle; that is a myth that deniers have invented to cast doubt on the importance of the decline in sea ice during the past 4 decades.

Edit: Sorry for off-topic response.
Title: Re: The 2018 melting season
Post by: Neven on May 25, 2018, 12:20:29 AM
Gary H. First this discussion is off-topic in the Melting Season thread. I suggest we continue this discussion here:

https://forum.arctic-sea-ice.net/index.php/topic,224.0.html

Thanks, Archimid. Let's stay on-topic (2018 melting season, ie now and short term). I would also advise people to not go the Steven Goddard route. I see where it leads to every day before flushing and it ain't pretty.  ;)
Title: Re: The 2018 melting season
Post by: numerobis on May 25, 2018, 12:26:26 AM
Back from troll-smashing: man it's been grey and cool (-5C to -10C when the norm is about 0C) in Iqaluit this May -- quite the opposite of April when it was sunny and warm (-5C to -10C when the norm is -10C to -15C).

For about two weeks, Environment Canada has been forecasting temperatures above freezing at the end of 3-5 days. Much like nuclear fusion being just around the corner, temperatures above freezing remain tantalizingly close. The floe edge opened up much closer than usual back in April, but I haven't seen chatter of any unusual melting -- quite the opposite.

Of course, that's balanced by warm and sunny conditions in the high Arctic which actually matters for the ice minimum.
Title: Re: The 2018 melting season
Post by: Ken Feldman on May 25, 2018, 12:39:21 AM
Beginning the analysis in 1979 is cherry picking. Why did we stop discussing the decades long increasing trend - leading up to 1979 - in Arctic sea ice extent? Noting that there's been a flat trend here for a decade is simply interesting in the moment. Does it perhaps suggest that we could be ending one cycle and beginning another? Also interesting that the Arctic sea ice volume is rather interesting in the moment.  http://ocean.dmi.dk/arctic/icethickness/thk.uk.php

One can toggle back - I just put May 23, 2008 side by side with yesterday's ice thickness - interesting.

 Graph was in the 1990 IPCC report.

Seems to me that the cherry pick is to go back to the 1990 report.  The most recent IPCC report was published in 2013.  Here is the comparable graphic from the current report:

http://www.climatechange2013.org/images/figures/WGI_AR5_Fig4-3.jpg

There is no "decades long increasing trend" that you refer to.  Interestly, after 1990 (you left all of that data off in your post), the trend is clearly downward.
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 25, 2018, 02:24:27 AM
Will the rather flat trend for the Sept min sea ice extent of the last decade, continue in 2018?

Very likely.
Title: Re: The 2018 melting season
Post by: litesong on May 25, 2018, 04:34:03 AM
The horizontal ten-years trend has no statistically significant difference with the decreasing forty-years trend.
Including the information that the solar TSI has been low for 11+ years(including a 3+ year period setting a 100 year record low)., may cause the flat Arctic sea ice trend to BE statistically significant.
Title: Re: The 2018 melting season
Post by: Lord M Vader on May 25, 2018, 09:12:46 AM
As we now are approaching June it's highly interesting to see if the current high pressure dome is going to remain in place over the Beaufort Sea and adjacent areas. Latest ECMWF 00z op run suggests that the HP will be in charge over the next 10 days. That should continue to bring warm and sunny weather conditions that should give an upshoot to melting momentum. And if that HP stays over Arctic for another 2-3 weeks it should render some serious damage to the sea ice at the Pacific side.

The only thing that would be worse than the current forecast is if we would see a Greenland Blocking High emerge in June. That would be a disaster!

At this moment we should be very grateful that this is 2018 and not 2013 or 2017!
Title: Re: The 2018 melting season
Post by: uniquorn on May 25, 2018, 10:43:45 AM
An area of ice south of the New Siberian Islands today showing different characteristics, darker red on terra/modis bands 3,6,7 (darker blue on 7,2,1). It appears to be persistant though previous days are too cloudy to be sure.
Is it thinner, thicker, wetter, saltier?
Title: Re: The 2018 melting season
Post by: FishOutofWater on May 25, 2018, 03:40:43 PM
Uniquorn, that color of blue on the false color is what it looks like when all the snow has melted off the ice and there's some meltwater or ponding on the surface of the ice. That's how I see it.
Title: Re: The 2018 melting season
Post by: uniquorn on May 25, 2018, 05:55:27 PM
Thank you FishOutofWater.

A couple of days of above zero temperatures are forecast for some of the Kara Sea. Clearer weather today allows a look at that area with worldview viirs brightness temperature band 15.

images are enhanced a little using imagej unsharp mask 1,0.6
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 25, 2018, 06:52:05 PM
Thank you FishOutofWater.

A couple of days of above zero temperatures are forecast for some of the Kara Sea. Clearer weather today allows a look at that area with worldview viirs brightness temperature band 15.

images are enhanced a little using imagej unsharp mask 1,0.6

Ice looks fairly healthy there and it is a little slow out of the gate.
Title: Re: The 2018 melting season
Post by: RoxTheGeologist on May 25, 2018, 08:29:58 PM
Ice looks fairly healthy there and it is a little slow out of the gate.

The Chukchi and CAB are the ones to watch for now. The Kara will more or less melt out entirely. It seems the Pacific side will have most of the interesting melt this year.
Title: Re: The 2018 melting season
Post by: gerontocrat on May 25, 2018, 09:19:42 PM
The Chukchi and CAB are the ones to watch for now. The Kara will more or less melt out entirely. It seems the Pacific side will have most of the interesting melt this year.
Given that I at the moment only believe GFS for 3-4 days ahead (if at all), the warmth seems to be coming from Central Siberia and heading all the way across to the Canadian Archipelago.
And maybe the Hudson will start to evaporate as will the snow in NE Canada ?

But the rest of the season? In the lap of the Gods.
Title: Re: The 2018 melting season
Post by: gerontocrat on May 25, 2018, 10:51:30 PM
Meanwhile, temperature North of 80 is not so hot.
Title: Re: The 2018 melting season
Post by: A-Team on May 26, 2018, 12:36:32 AM
Can someone please remind we why we keep copying over that stupid 80ºN line graph? Look at Zack's treatment below -- is 80ºN giving us the best sense of May temperatures over the Arctic? All it does is lower our group's credibility, already getting buried under ever-increasing off-topic negativity rants, driving Arctic Sea Ice traffic off to other sites.

Quote
Well above average temperatures over the #Arctic Ocean basin so far this month. "Colder" conditions over the surrounding region, particularly from the Hudson Bay to southern Greenland.
Quote
Warmth continues this spring on Svalbard... 5.5°C above average over the last 30 days at Longyearbyen (~78°N latitude). Sea ice in the region is a record low again.

Technical note: We are looking for grayscale intensity 2D maps so we can graphically multiply images to combine different effects into a resultant graphic, as only uncommonly do we have gridded netCDF files. The Arctic Ocean is huge and heterogenous. The melt season cannot be understood treating it as a single point.
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 26, 2018, 03:06:34 AM
Can someone please remind we why we keep copying over that stupid 80ºN line graph? Look at Zack's treatment below

Because that picture is too hard to understand.  the DMI 80N is clear and simple and easy to follow year to year.
Title: Re: The 2018 melting season
Post by: Alexander555 on May 26, 2018, 05:05:40 AM
And the North Pole is part of the planet and climate. Nobody is telling that it's only about that. Feel free to add quality as much as you want.
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 26, 2018, 05:18:09 AM
Certainly the graph is simplistic and the anomaly image provides far more info.

Not sure what the message of the last image is though.
Title: Re: The 2018 melting season
Post by: HapHazard on May 26, 2018, 09:25:45 AM
Thanks for all you do, A-Team. (and the last image made me laugh - and I also agree)
Title: Re: The 2018 melting season
Post by: Neven on May 26, 2018, 09:55:15 AM
The last image shows that all those off-topic discussions aren't held here, in this thread, or in the comment section of the ASIB. That was the whole idea of setting this forum up.
Title: Re: The 2018 melting season
Post by: gerontocrat on May 26, 2018, 11:13:13 AM
Can someone please remind we why we keep copying over that stupid 80ºN line graph? -- is 80ºN giving us the best sense of May temperatures over the Arctic?

I never expected to be told off for posting data. I don't expect the DMI will enjoy being told that the work they produce is stupid.

I posted it to contrast it the warmth flooding in from Central Siberia over much of the Arctic shown in the previous post with the temperatures north of 80.

So no, temperatures north of 80 obviously do not give a complete picture of the temperature, cloud cover, precipitation etc etc of the Arctic. But they are an element of that complete picture.

Off for a sulk and a whimper.
Title: Re: The 2018 melting season
Post by: oren on May 26, 2018, 12:34:08 PM
What A-Team means is that the proportion of posts in the forum having zero or near-zero relevance to arctic sea ice or to climate change in general has been rising rapidly, diluting the forum's contents and sharply increasing the level of animosity. When I first stumbled on this forum a few years back the amount of such garbage was negligent, and working down the unread topics list was a very strong introduction and educational experience. It took me months of lurking to dare post something, due to the high level of science-oriented discussions. Nowadays the unread topics list is mostly a heap of threads where the same tired posters incessantly bash each other over frivolities. Certainly this lowers the attractiveness of the forum for new and current science-oriented users, who may wander off to other sites or quit altogether, while rant-oriented users are attracted and proliferate.
Title: Re: The 2018 melting season
Post by: romett1 on May 26, 2018, 01:06:41 PM
Just wanted to say that I highly appreciate both A-Team's and gerontocrat posts. Sometimes you see something interesting and just post short comment, sometimes you prepare for a long time and post bit more informative posts - this is the way it should be.
Title: Re: The 2018 melting season
Post by: Pagophilus on May 26, 2018, 05:41:07 PM
In defense of gerontocrat:  I appreciate the focused, on-topic posts by both gerontocrat and A-team, and so many others here.   As gerontocrat pointed out, the 80 degrees N graph is data.  It is not poorly-founded speculation, or off-topic meandering, or trolling. 

The preconditioning of the ice in the CAB is surely of central interest with respect to what the situation will be like in September.  In my view the current and past variations in air temperatures summarized in the 80 degrees N graph give some useful information regarding that.  Looking back 10 years from now, who knows what we will find were the critical indicators for the health of the Arctic ice?
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 26, 2018, 07:08:30 PM
I occasionally post on these threads and it is usually just graphs with very personal surface observations. I would likely post DMI 80 but not now. I do post a lot in the consequences and policy sections and don't consider them off topic, just different topic. It is great to have them so these threads are focused on what matters.
Title: Re: The 2018 melting season
Post by: FishOutofWater on May 26, 2018, 08:42:37 PM
There's a negative correlation between the intensity of the Atlantic hurricane season and transport of heat from the tropics towards the pole on the Atlantic side. Thus, heat built up in the tropical Atlantic at an extremely high rate last July when the Arctic had cold weather.

This May, strong trade winds and intense storms in the Labrador sea, Greenland tip region have transported heat northwards at a far greater rate than normal. There is more heat available for melting ice and less for supporting intense hurricanes.

The weather patterns are subject to change this time of year so July could be very different from May, but I am very concerned about the rapid heating of the ocean this May in the Barents sea and far north Atlantic. It's great that the overturning circulation looks so strong in the Labrador sea, but it's draining cold fresh water that originated in the Arctic ocean and it's replacing it with warm salty water from both the Atlantic and Pacific oceans. There's going to be greater than normal Arctic ice melting from below this summer because of this oceanographic situation.

We got lucky last summer when July turned cold. I'm doubtful our luck will hold out another summer, but the weather constantly surprises me.
Title: Re: The 2018 melting season
Post by: Alexander555 on May 26, 2018, 09:29:16 PM
That anomaly east of the US. That  only counts for the top inch of the sea ,right ? Is it there every year ?
Title: Re: The 2018 melting season
Post by: Neven on May 26, 2018, 09:58:32 PM
Nowadays the unread topics list is mostly a heap of threads where the same tired posters incessantly bash each other over frivolities. Certainly this lowers the attractiveness of the forum for new and current science-oriented users, who may wander off to other sites or quit altogether, while rant-oriented users are attracted and proliferate.

I'm going to try and see if I can keep the 'Recent Posts' list exclusive for Arctic-related topics. I've tried this before, but couldn't find anything. I'll make more of an effort this time.

And otherwise, it might be best to get rid of the 'Recent Posts' list altogether, and I would recommend everyone to click the 'notify' button for the threads they're interested in (that's how I do it, I don't even watch the 'Recent Posts' list).

To be continued...

And sorry for the off-topic, but it is important.


Edit: Found something (http://custom.simplemachines.org/mods/index.php?mod=2975), will try to implement tomorrow, no time now.

Title: Re: The 2018 melting season
Post by: Hyperion on May 26, 2018, 10:35:10 PM
That anomaly east of the US. That  only counts for the top inch of the sea ,right ? Is it there every year ?
That's surface temperatures. But you could expect over 100m of a surface mixed zone to be similar. And the hottest water can be flowing in below that as its more saline and denser. Nullschool say its reaching over sixteen degrees where its popping its head up for a breath of air near Svalbard.
No that warm blob is not what we are used to seeing. The cold fresh  melt being swept across to the east Atlantic and flooding across the Tropics is new too. Same thing happened in the southern hemisphere six months ago. The atmospheric circulation systems have mutated into a vigorous direct tropics to polar and back heat exchange, the oceanic gyres have sped up. And a lot of the hot salty water is melting polar ice, becoming fresher and lighter, and returning to the tropics on the surface. Under turning rather than overturning. AMOC gone AMUC.
Title: Re: The 2018 melting season
Post by: Alexander555 on May 26, 2018, 11:16:50 PM
So it's the result of a flow. What is strange about it, the water north and south of it is colder than normal. That's why i could not really give it a cause. It's already there for several months at the same place.
Title: Re: The 2018 melting season
Post by: Steven on May 26, 2018, 11:22:56 PM
I'm going to try and see if I can keep the 'Recent Posts' list exclusive for Arctic-related topics. I've tried this before, but couldn't find anything. I'll make more of an effort this time.

It is already possibly at this moment to get the "recent comments" list for a specific board on the forum.  For example, this link:

https://forum.arctic-sea-ice.net/index.php?action=recent&board=3

shows the recent comments for the "arctic sea ice" board only.  I use it frequently.  Moreover, the parameter value at the end of the url can be changed for the other boards too, for example:

https://forum.arctic-sea-ice.net/index.php?action=recent&board=1

shows the recent comments for the "Consequences" board.
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 26, 2018, 11:57:29 PM
No that warm blob is not what we are used to seeing. The cold fresh  melt being swept across to the east Atlantic and flooding across the Tropics is new too. Same thing happened in the southern hemisphere six months ago. The atmospheric circulation systems have mutated into a vigorous direct tropics to polar and back heat exchange, the oceanic gyres have sped up. And a lot of the hot salty water is melting polar ice, becoming fresher and lighter, and returning to the tropics on the surface. Under turning rather than overturning. AMOC gone AMUC.

The cold spot in the North Atlantic has been there for a couple of years, and the Maine Lobsters have been migrating to Newfoundland for a while now, but the heat bloom in the Sargasso Sea is pretty new.

It could be a sign that the AMOC has stalled, but I think it is something else.  We will see if the Atlantic completely eats the Arctic ice on its side later this year.
Title: Re: The 2018 melting season
Post by: Pagophilus on May 27, 2018, 12:40:45 AM
That anomaly east of the US. That  only counts for the top inch of the sea ,right ? Is it there every year ?

No that warm blob is not what we are used to seeing. The cold fresh  melt being swept across to the east Atlantic and flooding across the Tropics is new too. Same thing happened in the southern hemisphere six months ago. The atmospheric circulation systems have mutated into a vigorous direct tropics to polar and back heat exchange, the oceanic gyres have sped up. And a lot of the hot salty water is melting polar ice, becoming fresher and lighter, and returning to the tropics on the surface. Under turning rather than overturning. AMOC gone AMUC.
I am puzzled.  Hasn't recent research https://www.nature.com/articles/d41586-018-04086-4 indicated that the AMOC (which includes the Gulf Stream, which is part of the North Atlantic oceanic gyre) has slowed in the past decade or so?   AMOC going AWOL?  Clarification would be welcome.
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 27, 2018, 01:23:38 AM
I am puzzled.  Hasn't recent research https://www.nature.com/articles/d41586-018-04086-4 indicated that the AMOC (aka the North Atlantic oceanic gyre) has slowed in the past decade or so?   AMOC going AWOL?  Clarification would be welcome.

The claim is there but so far the evidence has been pretty weak, and unless you can relate that to what is going on this Summer the discussion ought to continue elsewhere.  There is a warm pool in the Atlantic, but it will be months at least before that means anything.

What we know so far about the Atlantic as it relates to the Arctic this Summer is the continuing hot spots in the North...at least that is all I really know about this season.

Title: Re: The 2018 melting season
Post by: magnamentis on May 27, 2018, 01:59:09 AM
Nowadays the unread topics list is mostly a heap of threads where the same tired posters incessantly bash each other over frivolities. Certainly this lowers the attractiveness of the forum for new and current science-oriented users, who may wander off to other sites or quit altogether, while rant-oriented users are attracted and proliferate.

I'm going to try and see if I can keep the 'Recent Posts' list exclusive for Arctic-related topics. I've tried this before, but couldn't find anything. I'll make more of an effort this time.

And otherwise, it might be best to get rid of the 'Recent Posts' list altogether, and I would recommend everyone to click the 'notify' button for the threads they're interested in (that's how I do it, I don't even watch the 'Recent Posts' list).

To be continued...

And sorry for the off-topic, but it is important.


Edit: Found something (http://custom.simplemachines.org/mods/index.php?mod=2975), will try to implement tomorrow, no time now.

while as always things remain your choice i find every topic and everything people share in this forum interesting enough to read. does not necessarily mean that everything is good and agreed upon of course but before building an opinion of his own one should read.

for this reason i love the last read list because i simply open each one in a new tab and read or close the window if i have no time or no interest at the moment.

what's so difficult to choose and discard posts that are not for one person while another is interested and glad to be able to sift through them within half a minute or so?

one of the bigger while not recognized problems of our times is that everything has to be (is) specialised and fractured into a multitude of fields of expertise while in fact we should go back to see the whole picture more than detached details.

often solutions are making things worse because they are to narrow minded, focused on one or few fields of expertise while there is a complex system to deal with where everything is on whole.

a wholistic approach is what i'm talking about and the fact that many so called experts feel offended when they have to deal with information and discussions injected from the side is only making things worse.

another example how within a small group of people where the basic goal is the same or very similar, participants discredit each other.

BTW who complains about all this is off-topic him/herself and i totally disagree that an open discussion of any topic can be damaging itself.

if someone does not like some content he can simply go to the next post or skip for the moment.

we should pick up folks where they are, following a lonely eluded expert path will not lead to any mass-movement which is what we need to change the thinking pattern and behaviour of a multi-billion population.

i know the counter arguments to this which is why i said, your forum, your choice but i like it as it is.
Title: Re: The 2018 melting season
Post by: Hyperion on May 27, 2018, 08:41:16 AM
Quote
I am puzzled.  Hasn't recent research https://www.nature.com/articles/d41586-018-04086-4 indicated that the AMOC (which includes the Gulf Stream, which is part of the North Atlantic oceanic gyre) has slowed in the past decade or so?   AMOC going AWOL?  Clarification would be welcome.
Sure Pagophilus, there may have been some Gulfstream slowing at the time of publication of that paper. But now. Well we just ain't in Kansas anymore. :'(
The cyclone cannon that has fired up off new York is spitting a new one towards the south east coast of Greenland every couple of days. These have been sucking all the moisture and heat out of the tropical Atlantic and sweeping the warm tropical water along for the ride. Over the past couple of weeks they have been getting their tops ripped of by upper level winds about between Iceland and Greenland, though often reforming near Svalbard. Its striking how there is a strong river of air straight lining from the Western tropical Atlantic to nth of Finland at all tropospheric altitudes more often than not recently.
The anti clockwise rotation of these cyclones has also been persistently sucking northerlies down the west coast of Greenland. Some pics from this week:
Title: Re: The 2018 melting season
Post by: Hyperion on May 27, 2018, 09:04:43 AM
As for the AMOC, and bottom water production. That might be seriously compromised. For example the clockwise warm current around Greenland seems to, at least in part , east of Baffin island be getting turned back south. Possibly freshened and lightened from melting the base of Greenland glaciers and getting entrained in the south, then south east surface melt freshened low ssta flow  that's now crossing the Atlantic. Heat transport into the CAB certainly seems to have gone up a gear though with peak surface temps off Svalbard jumping nearly 2 degree s in two days.
Title: Re: The 2018 melting season
Post by: Hefaistos on May 27, 2018, 11:16:51 AM
Thanks Hyperion for interesting observations on the AMOC and current currents.
Having 16C SST just off Svalbard in May is outright scary.

OT: This SST hot spot is like a canary in a coal mine, although here the canary is already dead in the water, and the mine is already closed.
https://thebarentsobserver.com/en/arctic/2017/10/end-comes-100-years-norwegian-coal-mining-svalbard
Title: Re: The 2018 melting season
Post by: romett1 on May 27, 2018, 12:11:25 PM
5-day difference (May 26 vs May 21). Laptev, Baffin, Beaufort and Barents usual suspects. Kara and ESS are so far holding on. Images: ftp://ftp-projects.cen.uni-hamburg.de/seaice/AMSR2/
Title: Re: The 2018 melting season
Post by: Pagophilus on May 27, 2018, 12:51:08 PM
Thank you, Hyperion, for your reply and the useful information regarding the atmospheric weather systems moving energy from the Middle Atlantic towards the general area of Svalbard.  To clarify, my comments have all been with reference to ocean surface currents, which generally travel at least an order of magnitude slower than atmospheric storm systems, but which are important because they transport enormous amounts of energy.
 
Anomaly maps often require nuanced interpretation, but the significant gap in positive anomalies between the huge warm patch in the Middle Atlantic and the west coast of Britain and Ireland (the last image in your second post, showing Atlantic SSTA) at least raises the question as to the extent that the surface currents of the Atlantic ocean gyre are bringing extra warm water to the Svalbard region.  One would expect a continuous strong positive anomaly between the two areas if a lot of extra heat were being transferred thus.  That said, this SSTA map is just one small slice of data.
   
As to the Nature paper on the slowing of the Atlantic Ocean's circulation being out of date (it was published in April 2018), if there are more recently published studies showing that Atlantic circulation has speeded up recently, or indeed whether any oceanic gyre has speeded up recently, I would be most interested to read them.  Such information could be of immense significance for the Arctic ice sheet.
     
Quote
I am puzzled.  Hasn't recent research https://www.nature.com/articles/d41586-018-04086-4 indicated that the AMOC (which includes the Gulf Stream, which is part of the North Atlantic oceanic gyre) has slowed in the past decade or so?   AMOC going AWOL?  Clarification would be welcome.
Sure Pagophilus, there may have been some Gulfstream slowing at the time of publication of that paper. But now. Well we just ain't in Kansas anymore. :'(
The cyclone cannon that has fired up off new York is spitting a new one towards the south east coast of Greenland every couple of days. These have been sucking all the moisture and heat out of the tropical Atlantic and sweeping the warm tropical water along for the ride. Over the past couple of weeks they have been getting their tops ripped of by upper level winds about between Iceland and Greenland, though often reforming near Svalbard. Its striking how there is a strong river of air straight lining from the Western tropical Atlantic to nth of Finland at all tropospheric altitudes more often than not recently.
The anti clockwise rotation of these cyclones has also been persistently sucking northerlies down the west coast of Greenland. Some pics from this week:
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 27, 2018, 02:35:23 PM
I am puzzled.  Hasn't recent research https://www.nature.com/articles/d41586-018-04086-4 indicated that the AMOC (aka the North Atlantic oceanic gyre) has slowed in the past decade or so?   AMOC going AWOL?  Clarification would be welcome.

The claim is there but so far the evidence has been pretty weak, and unless you can relate that to what is going on this Summer the discussion ought to continue elsewhere.  There is a warm pool in the Atlantic, but it will be months at least before that means anything.

What we know so far about the Atlantic as it relates to the Arctic this Summer is the continuing hot spots in the North...at least that is all I really know about this season.

I agree with this. There is a warm pool in the Atlantic and a cold pool south of Greenland. The discussion on this thread about these two items should be its influence on weather patterns and melt for this season. For example, will such a set up result in more powerful storms? Let's watch.
Title: Re: The 2018 melting season
Post by: Shared Humanity on May 27, 2018, 02:38:04 PM
Quote
I am puzzled.  Hasn't recent research https://www.nature.com/articles/d41586-018-04086-4 indicated that the AMOC (which includes the Gulf Stream, which is part of the North Atlantic oceanic gyre) has slowed in the past decade or so?   AMOC going AWOL?  Clarification would be welcome.
Sure Pagophilus, there may have been some Gulfstream slowing at the time of publication of that paper. But now. Well we just ain't in Kansas anymore. :'(
The cyclone cannon that has fired up off new York is spitting a new one towards the south east coast of Greenland every couple of days. These have been sucking all the moisture and heat out of the tropical Atlantic and sweeping the warm tropical water along for the ride. Over the past couple of weeks they have been getting their tops ripped of by upper level winds about between Iceland and Greenland, though often reforming near Svalbard. Its striking how there is a strong river of air straight lining from the Western tropical Atlantic to nth of Finland at all tropospheric altitudes more often than not recently.
The anti clockwise rotation of these cyclones has also been persistently sucking northerlies down the west coast of Greenland. Some pics from this week:

Neat. This is exactly how the discussion about the warm pool should occur on the melting season thread.
Title: Re: The 2018 melting season
Post by: uniquorn on May 27, 2018, 02:41:45 PM
Thanks Hyperion for interesting observations on the AMOC and current currents.
Having 16C SST just off Svalbard in May is outright scary.

OT: This SST hot spot is like a canary in a coal mine, although here the canary is already dead in the water, and the mine is already closed.
https://thebarentsobserver.com/en/arctic/2017/10/end-comes-100-years-norwegian-coal-mining-svalbard

Niall Dollard started an interesting thread about the persistent null school SST hotspots near Svalbard here   
https://forum.arctic-sea-ice.net/index.php/topic,2194.msg133898.html#msg133898

A comparison with ecmwf is probably a good idea.
edit:posted image from windy
Title: Re: The 2018 melting season
Post by: uniquorn on May 27, 2018, 04:06:57 PM
Both ECMWF and GFS forecasting more warm winds for the Chukchi Sea from Tuesday onwards.
Image shows wed may30 forecast
Title: Re: The 2018 melting season
Post by: Hyperion on May 27, 2018, 04:49:43 PM
Quote
   t raises the question as to the extent that the surface currents of the Atlantic ocean gyre are bringing extra warm water to the Svalbard region.  One would expect a continuous strong positive anomaly between the two areas if a lot of extra heat were being transferred thus.   
Not really pagz. The warmest water is saltier and denser. The colder water flowing over the top insulates it preventing it radiating heat into space and being tubulated by wind and wave and losing heat by evaporation. Also the cold surge from the northwest and the warm surge from the Southwest are kind of like putting an open tube of toothpaste under a bladder of water, and then stepping left and right foot either side. Really salty and hot water could get a good spurt on from this. Making it past the faroes rise when it may have turned back south into the Atlantic. Re published.I ment  when did the data series end? We are seeing a hysteresis bifurcation. This is fast paced action here. Dorothy, meet Mr tornado.
Title: Re: The 2018 melting season
Post by: bbr2314 on May 27, 2018, 09:47:04 PM
The next two weeks should resolve almost all of the residual/ongoing snowfall anomalies across High Arctic-adjacent land bodies. It may not take that long for prolific amounts of heat to begin dumping into the Ocean itself, by way of the continents.

This is important, IMO, because, so far in 2018, I believe the vast majority of melt has been derived from oceanic anomalies. As the continents come into play, perhaps June takes a turn for the catastrophic, in terms of #s?

(https://www.tropicaltidbits.com/analysis/models/ecmwf/2018052712/ecmwf_z500aNorm_nhem_11.png)
Title: Re: The 2018 melting season
Post by: Hyperion on May 27, 2018, 10:04:24 PM
Here comes another, just like t' othas.
This happened in the south Pacific six months ago. Warm blob sucked out of the tropics filled the south Tasman with five degree anomalies. Even had a tropical cyclone spawn at 45 degrees sth off the coast of New Zealands sth island. Blob sat there for three months before being blown across sth of Tahiti, where its still feeding troppies where they ain't been before. Same phenomenon of cold water pushed towards the equator in the east and flooding westward across the equator also.
Shipping between Europe and Nth America will need to watch out for icebergs shortly.
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 27, 2018, 10:40:14 PM
Shipping between Europe and Nth America will need to watch out for icebergs shortly.

Please explain.
Title: Re: The 2018 melting season
Post by: bbr2314 on May 27, 2018, 10:47:12 PM
Shipping between Europe and Nth America will need to watch out for icebergs shortly.

Please explain.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fice-glaces.ec.gc.ca%2Fprods%2FWIS57SD%2F20180521180000_WIS57SD_0010044393.gif&hash=0f919e37af96bcec2d8ee996401362ca)
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 27, 2018, 10:52:53 PM
Eeep!  Now I need a translation.  Do they mean actual glacial bergs, or just slabs of sea ice?
Title: Re: The 2018 melting season
Post by: ghoti on May 27, 2018, 10:57:20 PM
Meanwhile the media are reporting a lack of icebergs near Newfoundland:

http://www.cbc.ca/news/canada/newfoundland-labrador/slow-start-to-iceberg-season-1.4679823 (http://www.cbc.ca/news/canada/newfoundland-labrador/slow-start-to-iceberg-season-1.4679823)
Title: Re: The 2018 melting season
Post by: bbr2314 on May 27, 2018, 10:59:23 PM
Meanwhile the media are reporting a lack of icebergs near Newfoundland:

http://www.cbc.ca/news/canada/newfoundland-labrador/slow-start-to-iceberg-season-1.4679823 (http://www.cbc.ca/news/canada/newfoundland-labrador/slow-start-to-iceberg-season-1.4679823)
Wonder if the season is delayed but not denied? Newfoundland may be lacking in bergs but snowfall is another story, apparently...

https://globalnews.ca/news/4228458/newfoundland-may-24-snowstorm-photos/

And re: Dharma, I believe the map references glacial bergs, not sea ice.
Title: Re: The 2018 melting season
Post by: FishOutofWater on May 28, 2018, 12:38:10 AM
The AMOC is not simple and the reports on it can be quite confusing because there are different measures of AMOC activity. Moreover, one part of the AMOC can be more active than another part.

There are peer reviewed reports of a general long-term slow down of the AMOC. I take no issue with those reports. The AMOC was relatively quite active between 1988 and 1995 when the Arctic oscillation was strongly positive. The far north Atlantic and the Arctic was very stormy in that period and cold fresh water in the Beaufort gyre was flushed and replaced with warm Atlantic water. After 1995 there was a general slow down in the AMOC as high pressure tended to dominate over the Arctic ocean. There was a severe slow down in the AMOC in 2010. It lead to a build up of tropical Atlantic heat, a bad hurricane season and a slowing of the Gulf Stream that caused flooding at Norfolk Va and other sea level sensitive areas on the U.S. east coast. After that, by some measures, the AMOC picked up. (https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.aoml.noaa.gov%2Fphod%2Fbin%2Fphplib%2Fpopup_image.php%3F%26amp%3BpImgUrl%3Dlatest.gif%26amp%3BpPageUrl%3Dhttp%3A%2F%2Fwww.aoml.noaa.gov%2Fphod%2Fsoto%2Fmht%2Fax7%2Freport.php%26amp%3BpSWidth%3D1440%26amp%3BpSHeight%3D900%26amp%3BpTitle%3DNOAA%2FAOML%2FPhOD&hash=65350339c9d9377a3e574f9051e6408f)

My statements about the AMOC this late winter and spring are based on Mercator ocean profiles, the persistent Greenland vortex at 500mb and the persistent storms that the vortex has been producing. What many readers don't seem to appreciate is that the warm SST pattern, off of the southeastern and mid-Atlantic states of the U.S. , is a feature that is quite deep. It's not just warm surface waters. The north wall of the Gulf stream goes down over 1000m.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fstatic-bulletin.mercator-ocean.fr%2Fimg%2F-1%2Fpsy4qv3r1%2F20180526%2Fat0%2FA%2Fpsy4qv3r1_20180526_at0_temperature_318m.png&hash=2b6cbc5bd10fca05ef3d504e184c077a)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fstatic-bulletin.mercator-ocean.fr%2Fimg%2F-1%2Fpsy4qv3r1%2F20180526%2Fat0%2FA%2Fpsy4qv3r1_20180526_at0_temperature_1062m.png&hash=63d2ed3f8843eebb856ea258171a04e0)

Likewise, the cold anomaly in the subpolar gyre reflects the effects of continued storms that have maintained deep water formation in the Labrador sea into late spring.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fstatic-bulletin.mercator-ocean.fr%2Fimg%2F-1%2Fsections%2Fpsy4qv3r1%2F20180526%2FA%2Fpsy4qv3r1_20180526_sarc1_temperature.png&hash=70d550338b6c256fcc82b79e11a6aff8)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fstatic-bulletin.mercator-ocean.fr%2Fimg%2F-1%2Fsections%2Fpsy4qv3r1%2F20180526%2FA%2Fpsy4qv3r1_20180526_sarc1_salinity.png&hash=ae926aeb8667aaacda1760e109eca45a)

The cooling of the tropical Atlantic over the past month is the result of stronger than normal trade winds that moved tropical heat into the subtropics and temperate regions.



To put it simply, the weather patterns this spring are normal patterns that have been intensified by an excess of heat in the northern hemisphere's oceans. The intensification of northward heat transport by the atmosphere is reflected downwards into the ocean. The end result is that the European - Atlantic side of the Arctic is heating up very rapidly this spring. I won't repeat showing the Levitus et all heat content map here, but it shows anomalous heat entering the Arctic from the Atlantic - not good for sea ice.

Title: Re: The 2018 melting season
Post by: Hyperion on May 28, 2018, 12:56:50 AM
Shipping between Europe and Nth America will need to watch out for icebergs shortly.

Please explain.

Well usually when Greenland glaciers calve they come down the coast on the Newfoundland current. Last year lots came past Newfoundland. And blobs of negative ssta water made it as far as Florida just off the coast. If the current weather patterns continue producing the surface currents we are seeing currently then the Newfoundland current may need to be renamed the Azores or even the Gibraltar current. Any bergs produced by calving pulses we will no doubt see in the next few months are likely to sweep south west straight across the major shipping routes. I hope the relevant services are not caught on the hop over this. If they are only monitoring 200 nautical mile coastal boundaries where they're used to seeing them, problems could ensue.
Title: Re: The 2018 melting season
Post by: dosibl on May 28, 2018, 04:49:35 PM
The Bering sea is about done accumulating albedo anomaly, SSTAs seem to be following suit.

https://earth.nullschool.net/#2018/05/27/0000Z/ocean/primary/waves/overlay=sea_surface_temp_anomaly/orthographic=-176.01,50.89,1201/loc=-179.226,55.238 (https://earth.nullschool.net/#2018/05/27/0000Z/ocean/primary/waves/overlay=sea_surface_temp_anomaly/orthographic=-176.01,50.89,1201/loc=-179.226,55.238)

https://earth.nullschool.net/#2017/05/27/0000Z/ocean/primary/waves/overlay=sea_surface_temp_anomaly/orthographic=-176.01,50.89,1201/loc=-179.226,55.238 (https://earth.nullschool.net/#2017/05/27/0000Z/ocean/primary/waves/overlay=sea_surface_temp_anomaly/orthographic=-176.01,50.89,1201/loc=-179.226,55.238)

https://earth.nullschool.net/#2016/05/27/0000Z/ocean/primary/waves/overlay=sea_surface_temp_anomaly/orthographic=-176.01,50.89,1201/loc=-179.226,55.238 (https://earth.nullschool.net/#2016/05/27/0000Z/ocean/primary/waves/overlay=sea_surface_temp_anomaly/orthographic=-176.01,50.89,1201/loc=-179.226,55.238)
Title: Re: The 2018 melting season
Post by: gerontocrat on May 28, 2018, 05:09:24 PM
The Bering sea is about done accumulating albedo anomaly, SSTAs seem to be following suit.
The Bering Sea started with very low ice area, which melted out quickly.
The earlier the melt, the higher the anomaly.
With all the sea ice gone,( except <4k km2), the anomaly cannot increase.

A good illustration of how early melting is the key to potential warming albedo, and why the 2016 anomaly was so much higher than 2012 even though the 2012 extent anomaly ended up 800,000+ km2 lower than 2016.

Title: Re: The 2018 melting season
Post by: gerontocrat on May 28, 2018, 05:22:16 PM
And while this Grumpy Old Man in The Gallery is here.

I've given up looking more than 2-4 days in advance.

The first image is cci-renalyzer showing a lot of warmth in the Arctic by May 31, even in Hudson and Baffin Bays, but excluding Kara and Laptev.

The second 2 images show why I prefer :-
 https://www.weather-forecast.com/maps/Arctic?over=pressure_arrows&symbols=cities.forecast.dots&type=wind.com  for wind and cloud cover.

My old eyes find these images so much easier to look at than the clever stuff elsewhere.

And the conclusion - melt is going to accelerate over the next few days.
Title: Re: The 2018 melting season
Post by: Sterks on May 28, 2018, 05:32:25 PM
Seems that May was much anomalously warmer in high latitudes than has been around my place, which is somewhere mid latitudes.
Spring is coming to the Arctic continental masses earlier, warmer than last year, that's for sure. Still not clear how it compares with other even warmer years, the average monthly statistics will say in about a week.
Title: Re: The 2018 melting season
Post by: aperson on May 28, 2018, 06:07:05 PM
I've given up looking more than 2-4 days in advance.

Thermodynamics on GFS has been completely busted recently which is what cci-reanalyzer relies on (as well as Earth nullschool and many other US-centric products). On intermediate ranges it has been increasing temperatures to unreasonable temperatures across the board. wx twitter recently pointed out that it was showing 45C+ solutions in Oklahoma that were both practically impossible and did not verify.

I've been using ECMWF on weather.us to get 3-7 day temperature estimates instead since the Euro doesn't seem to be having these sort of issues.
Title: Re: The 2018 melting season
Post by: Pagophilus on May 28, 2018, 07:20:57 PM
Thanks for this clear and scientific background information -- it helps me a lot!   

The AMOC is not simple and the reports on it can be quite confusing because there are different measures of AMOC activity. Moreover, one part of the AMOC can be more active than another part.

There are peer reviewed reports of a general long-term slow down of the AMOC. I take no issue with those reports. The AMOC was relatively quite active between 1988 and 1995 when the Arctic oscillation was strongly positive. The far north Atlantic and the Arctic was very stormy in that period and cold fresh water in the Beaufort gyre was flushed and replaced with warm Atlantic water. After 1995 there was a general slow down in the AMOC as high pressure tended to dominate over the Arctic ocean. There was a severe slow down in the AMOC in 2010. It lead to a build up of tropical Atlantic heat, a bad hurricane season and a slowing of the Gulf Stream that caused flooding at Norfolk Va and other sea level sensitive areas on the U.S. east coast. After that, by some measures, the AMOC picked up.    Etc.
Title: Re: The 2018 melting season
Post by: Pagophilus on May 28, 2018, 07:29:24 PM
This image from nullschool for May 26 shows the North Atlantic Current alive and well and at the surface, and emerging from the vast blob of heat in the Atlantic.  So perhaps no need for a hypothesis with surface ocean waters crossing over each other just yet...

Quote
   t raises the question as to the extent that the surface currents of the Atlantic ocean gyre are bringing extra warm water to the Svalbard region.  One would expect a continuous strong positive anomaly between the two areas if a lot of extra heat were being transferred thus.   
Not really pagz. The warmest water is saltier and denser. The colder water flowing over the top insulates it preventing it radiating heat into space and being tubulated by wind and wave and losing heat by evaporation. Also the cold surge from the northwest and the warm surge from the Southwest are kind of like putting an open tube of toothpaste under a bladder of water, and then stepping left and right foot either side. Really salty and hot water could get a good spurt on from this. Making it past the faroes rise when it may have turned back south into the Atlantic. Re published.I ment  when did the data series end? We are seeing a hysteresis bifurcation. This is fast paced action here. Dorothy, meet Mr tornado.
Title: Re: The 2018 melting season
Post by: Hyperion on May 28, 2018, 08:42:58 PM
Darn this corridor is active. Its approaching one cyclone per day spawning off new York. Though this gulf hurricane looks set to break the pattern a little by crashing the party.
Including three that have landed on Siberia, distinct circulation's still visible, one stuttering on Svalbard, I count eight in a neat arc. Similar game afoot in the nth Pacific too. Heat buildup there looking phantasmagorical.
I recall someone asked for continuous positive anomaly's Florida to Svalbard. Thanks to the 8m swells these are producing mixing the thin fresher surface with the much thicker warm layer below. You got it. Don't worry though. As it moves towards the southeast this will count as negative ssta still.
The rapid fire storm surges from these systems have major potential to pump the Gulfstream waters north and slosh the deep hot salty stuff over the ridge into the Arctic ocean IMHO.
Title: Re: The 2018 melting season
Post by: Alexander555 on May 28, 2018, 09:12:43 PM
It's pretty amazing to see that. I live just east of the UK. And we had our 8th May day above 25 degree C. That's the first time ever. Since they started to measure the temperature somewhere in 18xx it happend 3 times that we had 7 days above 25 degree C in May. And it will still be hot in the next days.
Title: Re: The 2018 melting season
Post by: FishOutofWater on May 28, 2018, 09:29:45 PM
I hope Europe doesn't develop another killer heat wave this summer. Tropical convection has been anomalously focused on Africa and the Indian ocean for the past 2 months. The MJO has been downright weird. doing 2 big loops over the Indian Ocean. In the summer of the killer heatwave in Europe there was a coupling between Indian ocean convection and European heat.

Whatever, the ECMWF continues to slam the Laptev sea with warm southerly winds over the next 10 days. It's another 10 bad days for sea ice. All the anomalous thickness on the Siberian side is going to be baked out quickly if this weather keeps up. This is what Atlantification looks like - storms tracking from the Atlantic into the Barents sea and storms swinging up from Siberia into the Laptev sea. The atmosphere is transporting heat very effectively this late spring with large elongated Rossby waves.
Title: Re: The 2018 melting season
Post by: Greenbelt on May 29, 2018, 04:01:43 AM
This year's extent numbers are very close to 2015, but the ice that was visible sure seemed a lot more melty looking three years ago.  Here's May 28, 2015 (above) and 2018 (below) from Worldview:
(https://gibs.earthdata.nasa.gov/image-download?TIME=2015149&extent=-2334720,-823296,819200,2158592&epsg=3413&layers=MODIS_Terra_CorrectedReflectance_TrueColor,Coastlines&opacities=1,1&worldfile=false&format=image/jpeg&width=616&height=582)
(https://gibs.earthdata.nasa.gov/image-download?TIME=2018148&extent=-2392064,-823296,819200,2084864&epsg=3413&layers=MODIS_Terra_CorrectedReflectance_TrueColor,Coastlines&opacities=1,1&worldfile=false&format=image/jpeg&width=627&height=568)
Title: Re: The 2018 melting season
Post by: Lord M Vader on May 29, 2018, 08:50:23 AM
The latest forecast from the Euro hints of a 969 hpa intensive cyclone over Kara Sea by D7. The winds should be of hurricane strength and tear the sea ice apart and flush it out to the Atlantic death zone.
Title: Re: The 2018 melting season
Post by: numerobis on May 29, 2018, 01:34:34 PM
The Canadian model has been desperately trying to get Iqaluit above freezing, but seems powerless to make it happen. The forecast keeps getting closer but yesterday again it only hit -1.1 C when the forecast was 0 C.

I’m curious what it is that’s making the models run so warm (ECMWF seems to not be having this problem).
Title: Re: The 2018 melting season
Post by: ghoti on May 29, 2018, 03:01:37 PM
The Canadian model has been desperately trying to get Iqaluit above freezing, but seems powerless to make it happen. The forecast keeps getting closer but yesterday again it only hit -1.1 C when the forecast was 0 C.

I’m curious what it is that’s making the models run so warm (ECMWF seems to not be having this problem).
You of course have seen Rick Mercer's take on the Environment Canada forecasts? ( https://youtu.be/wkDvqQKGgDA )
Title: Re: The 2018 melting season
Post by: bbr2314 on May 29, 2018, 07:12:46 PM
The Canadian model has been desperately trying to get Iqaluit above freezing, but seems powerless to make it happen. The forecast keeps getting closer but yesterday again it only hit -1.1 C when the forecast was 0 C.

I’m curious what it is that’s making the models run so warm (ECMWF seems to not be having this problem).
I believe that they are failing to cope with excessive extant snowcover across regions where it should no longer exist, but I could be incorrect. I know the GFS suffers particularly from this issue, but perhaps as we head deeper into spring and approach summer, the CMC is also impacted?

The EURO has also been consistently far too rushed in ejecting cold from Quebec/environs.
Title: Re: The 2018 melting season
Post by: Pagophilus on May 29, 2018, 08:14:22 PM
In this context, the snow cover, according to NOAA/National Weather Service, has declined on a significant scale in Siberia over the past five days, particularly in the region adjacent to the Laptev Sea.  North American snow cover looks more stable over this period.


I’m curious what it is that’s making the models run so warm (ECMWF seems to not be having this problem).
I believe that they are failing to cope with excessive extant snowcover across regions where it should no longer exist, but I could be incorrect. I know the GFS suffers particularly from this issue, but perhaps as we head deeper into spring and approach summer, the CMC is also impacted?
Title: Re: The 2018 melting season
Post by: uniquorn on May 29, 2018, 08:47:24 PM
ECMWF forecast for pacific side is warmer than GFS on sunday.
Title: Re: The 2018 melting season
Post by: bbr2314 on May 29, 2018, 10:48:09 PM
In this context, the snow cover, according to NOAA/National Weather Service, has declined on a significant scale in Siberia over the past five days, particularly in the region adjacent to the Laptev Sea.  North American snow cover looks more stable over this period.

It is interesting that the decline in Laptev-adjacent cover coincides exactly with the recent drop in area/ "blue-ing" of the ice adjacent to the increasingly snow-free land. I think this solidifies the idea that snow-covered land adjacent to sea ice is a critical factor in mitigating the effects of continental warmth.

As we see snow extent continue to drop, this should accelerate over the coming days as well. It is interesting that the departures on CCIN are a bit more dramatic than those on Rutgers, and while area is over +1SD vs. normal,  SWE is still much, much higher vs. normal. This is (IMO) critical as the snow-adjacent areas have much higher albedos vs. previous years which, to date, has further aided in mitigating incoming continental warmth.

We can actually see this manifest explicitly in the recent temp anomalies. Scandinavia, which lost almost all of its cover prior to other Arctic-adjacent land regions, has served as the anchor for a torch into the high ATL. With Alaska and the NW Territories/Yukon now following, it looks like Beaufort should be absolutely hammered as we head into June.
Title: Re: The 2018 melting season
Post by: Neven on May 29, 2018, 11:17:05 PM
It's still mostly high pressure lingering over most of the Arctic in the 6-day ECMWF forecast (as provided by Tropical Tidbits), but it's weak and there aren't any interesting clusters of isobars to speak of. However, there is something shaping up towards the end of the forecast, which could potentially lead to a Dipole. I'm tempted to post the forecast for beyond D6, because it shows a very significant Dipole, but I'll hold out.
Title: Re: The 2018 melting season
Post by: Hyperion on May 29, 2018, 11:53:54 PM
Quote
With Alaska and the NW Territories/Yukon now following, it looks like Beaufort should be absolutely hammered as we head into June.

There certainly looks to be a lot of tropical Pacific heat and moisture inbound. With another low pressure system developing north of Japan this corridor may be shifting up a gear indeed.
Title: Re: The 2018 melting season
Post by: oren on May 30, 2018, 02:31:52 AM
In this context, the snow cover, according to NOAA/National Weather Service, has declined on a significant scale in Siberia over the past five days, particularly in the region adjacent to the Laptev Sea.  North American snow cover looks more stable over this period.
It is interesting that the decline in Laptev-adjacent cover coincides exactly with the recent drop in area/ "blue-ing" of the ice adjacent to the increasingly snow-free land. I think this solidifies the idea that snow-covered land adjacent to sea ice is a critical factor in mitigating the effects of continental warmth.
Correlation is not necessarily causation. It could very well be that when the warm weather arrives (as in Laptev-adjacent) land snow melts and sea ice starts declining, while when cold weather lingers (as in  NE Quebec) snow is anomalously deep and sea ice melts slowly. It doesn't mean the land snow is causing the weather to happen.
Title: Re: The 2018 melting season
Post by: aperson on May 30, 2018, 02:48:55 AM
It's still mostly high pressure lingering over most of the Arctic in the 6-day ECMWF forecast (as provided by Tropical Tidbits), but it's weak and there aren't any interesting clusters of isobars to speak of. However, there is something shaping up towards the end of the forecast, which could potentially lead to a Dipole. I'm tempted to post the forecast for beyond D6, because it shows a very significant Dipole, but I'll hold out.

How does EPS look? I'm not sure what feature you're searching for.
Title: Re: The 2018 melting season
Post by: bbr2314 on May 30, 2018, 02:50:18 AM
In this context, the snow cover, according to NOAA/National Weather Service, has declined on a significant scale in Siberia over the past five days, particularly in the region adjacent to the Laptev Sea.  North American snow cover looks more stable over this period.
It is interesting that the decline in Laptev-adjacent cover coincides exactly with the recent drop in area/ "blue-ing" of the ice adjacent to the increasingly snow-free land. I think this solidifies the idea that snow-covered land adjacent to sea ice is a critical factor in mitigating the effects of continental warmth.
Correlation is not necessarily causation. It could very well be that when the warm weather arrives (as in Laptev-adjacent) land snow melts and sea ice starts declining, while when cold weather lingers (as in  NE Quebec) snow is anomalously deep and sea ice melts slowly. It doesn't mean the land snow is causing the weather to happen.

OK, so why is it then that the Arctic has held up remarkably well outside of areas adjacent to the oceanic heat? A satellite comparison between this year and previous years shows that the albedo this year is very noticeably higher versus all others besides perhaps 2009.

I would argue that the strength of Kara due to the anomalous adjacent cover despite all the weakness elsewhere is further confirmation of ^^.

But perhaps you are right!
Title: Re: The 2018 melting season
Post by: bbr2314 on May 30, 2018, 02:51:58 AM
It's still mostly high pressure lingering over most of the Arctic in the 6-day ECMWF forecast (as provided by Tropical Tidbits), but it's weak and there aren't any interesting clusters of isobars to speak of. However, there is something shaping up towards the end of the forecast, which could potentially lead to a Dipole. I'm tempted to post the forecast for beyond D6, because it shows a very significant Dipole, but I'll hold out.

How does EPS look? I'm not sure what feature you're searching for.
The EPS are horrific.

(https://www.tropicaltidbits.com/analysis/models/ecmwf-ens/2018052912/ecmwf-ens_T850a_nhem_11.png)

It looks like the end of snow over NWT/Alaska is going to allow the Beaufort to torch and combined with what's happened in Siberia, continental heat should begin accumulating over the Arctic posthaste.
Title: Re: The 2018 melting season
Post by: bbr2314 on May 30, 2018, 04:06:17 AM
Something else to be noted is the models (GFS CMC EURO) are now developing the first real tropical system of the Western Pacific season. The GFS is particularly insane. While the storm is strong, its aerial coverage as predicted here is.... immense. In any case, if this does develop, I would think it portends a major melt event / another GAC besides the Laptev event around 6/10-12.

(https://www.tropicaltidbits.com/analysis/models/gfs/2018052918/gfs_ir_ea_33.png)

In fact, this is indeed what the GFS shows rolled forward into fantasy land... obviously *very* far out but we should watch the WPAC closely because if this does occur it would be nothing short of catastrophic for the sea ice:

(https://www.tropicaltidbits.com/analysis/models/gfs/2018052918/gfs_z500_mslp_nhem_48.png)

(https://www.tropicaltidbits.com/analysis/models/gfs/2018052918/gfs_z500aNorm_nhem_48.png)
Title: Re: The 2018 melting season
Post by: bbr2314 on May 30, 2018, 06:22:18 AM
00z GFS maintains an impending / worsening torch over Siberia as the snowcover continues to melt... by D4-5-6 it is sufficient to sustain our first GAC of the season across Laptev, while torching also commences across Beaufort, Chukchi, ESS, and most of the CAB. Hudson, Baffin, and Kara look to maintain relatively cool temps.

(https://www.tropicaltidbits.com/analysis/models/gfs/2018053000/gfs_T2m_nhem_26.png)

I would think that this will cause melt-ponding over most of the thickest remaining ice, while leaving the ice that's going to melt out anyways relatively intact... for the time being. This will probably have bad implications for final seasonal #s. But will it be enough for #1?

Title: Re: The 2018 melting season
Post by: jdallen on May 30, 2018, 07:59:31 AM
<snippage>... However, there is something shaping up towards the end of the forecast, which could potentially lead to a Dipole. <more snippage>

I can see that dipole starting to organize on day 6 in your graphics.  Considering corroborating runs in other models, it's pretty persuasive.

I'm also noting the references to storms starting to form and churn up the Asian and N. American continental margins.  I see a situation where we start seeing alternating inputs of heat and moisture from further south punctuated by dipoles.  I'm going to go out on a limb to predict that one of those pulses of heat and moisture will bring significant rain into the CAB mid to late June.
Title: Re: The 2018 melting season
Post by: Neven on May 30, 2018, 08:50:53 AM
I can see that dipole starting to organize on day 6 in your graphics.  Considering corroborating runs in other models, it's pretty persuasive.

It's gone again from today's 00Z forecast. I'm glad I didn't post anything from D7-10 yesterday. Looks completely different now!
Title: Re: The 2018 melting season
Post by: jdallen on May 30, 2018, 12:32:00 PM
I can see that dipole starting to organize on day 6 in your graphics.  Considering corroborating runs in other models, it's pretty persuasive.

It's gone again from today's 00Z forecast. I'm glad I didn't post anything from D7-10 yesterday. Looks completely different now!
Well good. You know part of my plan to save the ice involves making predictions that force the weather to change in order to embarrass me, right?  :P
Title: Re: The 2018 melting season
Post by: echoughton on May 30, 2018, 12:46:27 PM
Melt season looking pretty ho-hum thus far. I see you mention dipole, Neven. Should post in stupid questions bin but what is a dipole? And how do you "like" comments? I see many likes but can't figure it out.
Title: Re: The 2018 melting season
Post by: Pagophilus on May 30, 2018, 12:51:08 PM
More on the Laptev.  The significant gap in the Laptev has opened over just an 8 day period.  It really began around May 21 and by May 29 it has become a 1000 km long stretch of open water, almost 200 km wide at its maximum point and about 100 km wide for much of the rest of its length.  Comparing the two images below, it is to me the biggest visual change in the last week (the Barents meltout is impressive too).

I looked back through the AMSR2 maps for the end of May (they were only available it seemed back to 2013) and the only year there was such a gap in the Laptev was in 2014.  That May 2014 opening seemed to be a gap with tensional origins that took about 2 weeks to develop fully.  The opening began in the East Siberian Sea and subsequently slid over to the Laptev over that period.   

So is the origin of this gap tensional? Or warm upwelling waters? Or...?  Worldview images (one is below) indicate that much of the south side (top of picture) of the current gap is solid ice (fast ice?) and the north side consists of large and small floes, maybe bound by some thinner ice. 

And is this rapid change in any way significant?  I realize that over the longer term this sort of thing may have happened routinely, but in my experience this change seems impressive in rate and magnitude.  Either way, as long as it is open, the gap is going to suck up significant solar energy when the sun shines in the Laptev, and warm those surface waters.
Title: Re: The 2018 melting season
Post by: be cause on May 30, 2018, 01:32:32 PM
re the Laptev gap .. it has been opening and closing for some time .. look at worldview in mid April for example .. looks like it will not be closing again 'till the refreeze (assuming there is one ) . The fracture that is still largely the southern ice edge has been present all spring and a lot of ice to the north is less than 3 months old .. b.c.
Title: Re: The 2018 melting season
Post by: uniquorn on May 30, 2018, 01:38:31 PM
yes, Laptev has been quite mobile all melting season.
Title: Re: The 2018 melting season
Post by: uniquorn on May 30, 2018, 01:47:14 PM
An update on our thickest area of ice according to PIOMAS. Worldview and Polarview may29.

Thanks to Wipneus for piomas image
Worldview images enhanced using imagej unsharp mask 1,0.6
Title: Re: The 2018 melting season
Post by: Neven on May 30, 2018, 02:00:11 PM
Should post in stupid questions bin but what is a dipole?

A Dipole is basically an atmospheric set-up that involves a low pressure system and a high pressure system (Dipole=two poles) opposite from each other, causing very strong winds between them. In the Arctic, most of the time, the high pressure will be above the American side of the Arctic, while the low pressure is on the Siberian side.

I posted an example (https://forum.arctic-sea-ice.net/index.php/topic,2278.msg155266.html#msg155266) last week, showing that winds would probably cause the ice to open up in the Laptev.

Also see this Wikipedia entry (https://en.wikipedia.org/wiki/Arctic_dipole_anomaly).

Quote
And how do you "like" comments? I see many likes but can't figure it out.

The 'like' system isn't working as it should yet. At the top of every comment there should be a 'like' button net to the 'quote' button, but not everyone is seeing it.
Title: Re: The 2018 melting season
Post by: Dharma Rupa on May 30, 2018, 02:15:50 PM
This will put the Laptev opening into some context, though it would be nice to have a few more years:
Title: Re: The 2018 melting season
Post by: oren on May 30, 2018, 02:28:25 PM
So is the origin of this gap tensional? Or warm upwelling waters? Or...?  Worldview images (one is below) indicate that much of the south side (top of picture) of the current gap is solid ice (fast ice?) and the north side consists of large and small floes, maybe bound by some thinner ice. 
The origin is transport of the mobile ice away from the fast ice. The ice in that region is quite thick, and could not reach a complete meltout at this early date even with warm water upwelling. On the other hand, the exposed region is not refreezing anymore, which does tell us something about the local conditions.
Title: Re: The 2018 melting season
Post by: gerontocrat on May 30, 2018, 02:32:20 PM
And a couple of Laptev AREA graphs
Title: Re: The 2018 melting season
Post by: Pagophilus on May 30, 2018, 03:32:16 PM
Thank you, uniquorn, be cause, oren and dharma for taking the time to explain.  My education continues...

yes, Laptev has been quite mobile all melting season.
Title: Re: The 2018 melting season
Post by: Neven on May 30, 2018, 03:48:46 PM
Here's how things ended up in 2014, with the Laptev Bite reaching 85N:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fneven1.typepad.com%2F.a%2F6a0133f03a1e37970b01b7c6d86daa970b-800wi&hash=209a34c08f1354a313c84575f7a62ccb)
Title: Re: The 2018 melting season
Post by: bbr2314 on May 30, 2018, 05:13:40 PM
So is the origin of this gap tensional? Or warm upwelling waters? Or...?  Worldview images (one is below) indicate that much of the south side (top of picture) of the current gap is solid ice (fast ice?) and the north side consists of large and small floes, maybe bound by some thinner ice. 
The origin is transport of the mobile ice away from the fast ice. The ice in that region is quite thick, and could not reach a complete meltout at this early date even with warm water upwelling. On the other hand, the exposed region is not refreezing anymore, which does tell us something about the local conditions.
The origin is therefore not transport, which has been ongoing all winter. Rather, it is the lack of refreeze, which has resulted because of the snowmelt across adjacent Siberian landmass. Now, continental heat is pouring into Laptev (most days), and is the reason refreeze is no longer occurring / open water is now showing.
Title: Re: The 2018 melting season
Post by: Pagophilus on May 30, 2018, 05:19:36 PM
So, thinking aloud, the little bobbles on the flat line part of the plot for 2018 are probably the gap opening and closing as per uniquorn's video, and the recent steep drop is the gap opening wide this past week.  Other years than 2014 may well have had steep drops like this prior to 2010, but these would not be discernible in the decadal average lines.  And where it goes from here is uncertain...

And a couple of Laptev AREA graphs
Title: Re: The 2018 melting season
Post by: A-Team on May 30, 2018, 05:49:34 PM
The situation in the Chukchi, which is opening up rapidly from wind and melt, currently has ice favorable for walruses who feed primarily at Hanna Shoal (which is not only fairly shallow but is swept by a nutrient-rich current favorable to filter-feeder growth). However if the ice retreats like it did last year the walruses will again have a two-week swim from a dangerous shore haul-out which is calorically unworkable for reproduction.

It's not clear that the 2010-2018 comparison of nine years of Ascat on May 28th is all that informative but it's shown below anyway; this year resembles 2016 more than 2017. The right-angle elbow in the Chukchi of the Beaufort stringer of CAA ice has no recent counterpart. It results from persistent strong westward winds off the Alaskan shore meeting northward winds (or currents) through the Bering Strait. Winds otherwise have been blah, with little Fram export and not much on the GFS horizon.
Title: Re: The 2018 melting season
Post by: gerontocrat on May 30, 2018, 06:11:44 PM
So, thinking aloud, the little bobbles on the flat line part of the plot for 2018 are probably the gap opening and closing as per uniquorn's video, and the recent steep drop is the gap opening wide this past week.  Other years than 2014 may well have had steep drops like this prior to 2010, but these would not be discernible in the decadal average lines.  And where it goes from here is uncertain...

I think logic says that early in the year - damn cold - wobbles come from wind, sea currents and waves moving ice. But now there is real warmth melting ice, warming up ice and thinning ice making it much easier to shift. So area loss is now a mixture.

And just to make life more complicated, have another look back at where the crack is - at https://forum.arctic-sea-ice.net/index.php/topic,2278.msg156505.html#msg156505 .

Fractured messy ice to the north, what looks like a smooth ice layer closer to the Russian shore.

Now look at the arctic bathymetry map below at the Laptev shelf.

Is there a correlation between the line of the fracture and the 10-25 metre sea depth contour?
Title: Re: The 2018 melting season
Post by: FishOutofWater on May 30, 2018, 06:25:30 PM
We shouldn't forget the vorticity of water masses. Because of the spin of the earth, the Coriolis effect tends to turn water masses to the right as they move north or south. Thus, Siberian shelf water tends to hug the coast of Siberia as it moves towards the Bering Strait and Pacific water tends to hug the Alaskan coast as it moves north from the Bering strait. The Beaufort gyre, however is an area of high sea surface heights under an atmospheric high pressure area and they both rotate clockwise.

The inevitable interaction of these different water masses leads to swirling eddies on the margins of the water masses. The position of the center of the Beaufort high has moved polewards this year compared to last year in response to months of anomalous southerly winds.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fstatic-bulletin.mercator-ocean.fr%2Fimg%2F-1%2Fpsy4qv3r1%2F20170529%2Farc%2FA%2Fpsy4qv3r1_20170529_arc_sea_surface_height_0m.png&hash=1a3891b7d9b5898da434d0b332f433b4)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fstatic-bulletin.mercator-ocean.fr%2Fimg%2F-1%2Fpsy4qv3r1%2F20180529%2Farc%2FA%2Fpsy4qv3r1_20180529_arc_sea_surface_height_0m.png&hash=eed22151c7e61a5aa3161a20d07f35af)
At the same time the southerly winds and strong sea surface height gradient intensified the Alaska coastal current driving anomalously salty water deeper into the Arctic than last year.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fstatic-bulletin.mercator-ocean.fr%2Fimg%2F-1%2Fpsy4qv3r1%2F20170529%2Farc%2FA%2Fpsy4qv3r1_20170529_arc_salinity_34m.png&hash=6a80e3ef16867437ce68dec2aaf384a8)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fstatic-bulletin.mercator-ocean.fr%2Fimg%2F-1%2Fpsy4qv3r1%2F20180529%2Farc%2FA%2Fpsy4qv3r1_20180529_arc_salinity_34m.png&hash=ee7691120e9aeb31aebf14d6b3a2abd3)

Also note that the Laptev polynya forms at the edge of the shallow Siberian shelf. Offshore winds push ice towards the pole and saltier water wells up from below during southerly wind events. At this time of year, those winds are warm and lead to open water. In winter those winds are cold and cause rapid refreezing.

Cause and effect thinking isn't very useful in a complex, coupled system. To the person who wrote that this melt season isn't very impressive - we will see. This year's extent is the second lowest on record for this date and ice thickness is more evenly distributed across the Arctic this year than in other years. There's more ice to melt out on the Siberian side, but much of it will melt out. The weather models are all inconsistent beyond 5 days so it's anyone's guess what the weather will do and how much ice volume will melt out. This year's more even distribution of volume could lead to an extent cliff in mid to late summer. Again, we'll see.
Title: Re: The 2018 melting season
Post by: bbr2314 on May 30, 2018, 06:48:45 PM
It looks like the Pacific intrusion has combined with Atlantification to effectively split the halocline in two. This is apparent in the "fingers" of both Pacific and Atlantic water meeting up in the vicinity of Wrangel Island this year, whereas in 2017, the freshwater dome maintained integrity. This will probably have major implications as we head deeper into the melt season (I would think as melt progresses and the two fingers begin interacting more, there will be a push/pull of ATL/PAC water into the Arctic as the halocline is increasingly exiled from the CAB itself).
Title: Re: The 2018 melting season
Post by: uniquorn on May 30, 2018, 09:52:09 PM
Floes south of wrangel island moving at ~15km/day over the last 3 days on worldview.
imagej brightness contrast 41,255

amsr2 UHH pacific side for this melting season. On the cusp of another pulse?
Title: Re: The 2018 melting season
Post by: Pagophilus on May 31, 2018, 01:28:35 AM

Now look at the arctic bathymetry map below at the Laptev shelf.

Is there a correlation between the line of the fracture and the 10-25 metre sea depth contour?

Those of a delicate disposition might want to avert their eyes.  I found a rough bathymetric map of the Laptev, and then took the AMSR2 image and tweaked it until its coastlines corresponded roughly with those of the bathymetric map.  And indeed, as uniquorn says and you surmise, most of the southern edge of the Laptev opening closely follows the 30m submarine contour with the exception of the section around Kotelny (?) Island.  Just having a little fun here, and avoiding some less interesting work in the process.  Of course now I am wondering why it follows the shelf contour, and what effect does the Lena river (which looks pretty large) have on the melting.
Title: Re: The 2018 melting season
Post by: oren on May 31, 2018, 02:46:03 AM
Here's why the Laptev gap stopped refreezing. A chart of Tiksi air temperatures in May, with comparison to climatology, courtesy of http://www.pogodaiklimat.ru/monitor.php?id=21824 (http://www.pogodaiklimat.ru/monitor.php?id=21824) (in Russian). The average temp crossed 0oc on the 23rd, and stayed above it since.

Note to bbr1234, high temps cause snow melt, not the other way around (snow melt does not cause high temps). Snow in Tiksi finished melting today, according to Ogimet (https://www.ogimet.com/cgi-bin/gsynres?lang=en&ord=REV&ndays=50&ind=21824)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.pogodaiklimat.ru%2Fgraf%2Frus%2F2018%2F21824_201805.gif&hash=11c73376d6814cf4a7311e0837743d56)
Title: Re: The 2018 melting season
Post by: Frivolousz21 on May 31, 2018, 02:51:56 AM
The models are wild in the Day 5+ range

But they are locked in on substantial warm and sun over a large part of the Arctic basin.

Focused heavily on the Pacific side into the CAB.


The euro straight keeps the CAB warm through the entire run.
Title: Re: The 2018 melting season
Post by: Frivolousz21 on May 31, 2018, 02:58:10 AM
You can see the slow progressive warmth..

With a general Southerly flow into the Pacific side.

Don't get me wrong.  I'm sure those temps are well above normal over the CAB.
Title: Re: The 2018 melting season
Post by: Michael Hauber on May 31, 2018, 03:21:56 AM
In my opinion the Laptev gap was a bit bigger same day of year in 2007.
Title: Re: The 2018 melting season
Post by: bbr2314 on May 31, 2018, 04:31:16 AM
Here's why the Laptev gap stopped refreezing. A chart of Tiksi air temperatures in May, with comparison to climatology, courtesy of http://www.pogodaiklimat.ru/monitor.php?id=21824 (http://www.pogodaiklimat.ru/monitor.php?id=21824) (in Russian). The average temp crossed 0oc on the 23rd, and stayed above it since.

Note to bbr1234, high temps cause snow melt, not the other way around (snow melt does not cause high temps). Snow in Tiksi finished melting today, according to Ogimet (https://www.ogimet.com/cgi-bin/gsynres?lang=en&ord=REV&ndays=50&ind=21824)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.pogodaiklimat.ru%2Fgraf%2Frus%2F2018%2F21824_201805.gif&hash=11c73376d6814cf4a7311e0837743d56)
Why are you so rude to me? I never said high temps do not cause snow melt. Once snow has fully melted, temps can soar significantly higher. When snow is extant, it modifies airmasses and reduces temperatures (E.G., you are not going to see 85-90F temps with substantial snowcover on the ground). You will see several days of above-freezing temps ranging up to 50-60, it will melt, and then you will see temps shoot up.
Title: Re: The 2018 melting season
Post by: oren on May 31, 2018, 05:25:31 AM
Here's why the Laptev gap stopped refreezing. A chart of Tiksi air temperatures in May, with comparison to climatology, courtesy of http://www.pogodaiklimat.ru/monitor.php?id=21824 (http://www.pogodaiklimat.ru/monitor.php?id=21824) (in Russian). The average temp crossed 0oc on the 23rd, and stayed above it since.

Note to bbr1234, high temps cause snow melt, not the other way around (snow melt does not cause high temps). Snow in Tiksi finished melting today, according to Ogimet (https://www.ogimet.com/cgi-bin/gsynres?lang=en&ord=REV&ndays=50&ind=21824)
Why are you so rude to me? I never said high temps do not cause snow melt. Once snow has fully melted, temps can soar significantly higher. When snow is extant, it modifies airmasses and reduces temperatures (E.G., you are not going to see 85-90F temps with substantial snowcover on the ground). You will see several days of above-freezing temps ranging up to 50-60, it will melt, and then you will see temps shoot up.
First, I apologize. I did not mean the statement to come out as rude, but upon re-reading it does feel rude. Sorry. I will refrain from similar-spirited comments in the future.

I was responding to a previous statement you made:
The origin is therefore not transport, which has been ongoing all winter. Rather, it is the lack of refreeze, which has resulted because of the snowmelt across adjacent Siberian landmass. Now, continental heat is pouring into Laptev (most days), and is the reason refreeze is no longer occurring / open water is now showing.
Which seemed to me to reverse the causal chain. In my view, lack of refreeze came when temps rose above zero, and at that point snow started to melt as well, therefore the snowmelt was not the cause of the lack of refreeze, rather both were the result of a third factor - temperatures.
Title: Re: The 2018 melting season
Post by: wallen on May 31, 2018, 11:07:23 AM
Haven't seen any reference to the McKenzie river this year. Looks to be just starting to impact on the Beaufort Sea. Will be worth watching this year.
Title: Re: The 2018 melting season
Post by: gerontocrat on May 31, 2018, 11:09:36 AM

And indeed most of the southern edge of the Laptev opening closely follows the 30m submarine contour with the exception of the section around Kotelny (?) Island. Of course now I am wondering why it follows the shelf contour, and what effect does the Lena river (which looks pretty large) have on the melting.
The Lena River is certainly a big beast, with a huge maximum discharge when the snow melts. June is the big month - but apparently snow-melting is also happening in May now. Presumably large amounts (200gt ?) of fresh water entering the Laptev in just one month must impact how ice loss happens in the Laptev.   See data below and images attached.

And yes, this stuff is a wonderful distraction from less interesting but necessary work

From Wikipedia:-
The Lena (Russian: Ле́на, IPA: [ˈlʲɛnə]; Russian Buryat: Зүлхэ; Evenki: Елюенэ; Sakha: Өлүөнэ) is the easternmost of the three great Siberian rivers that flow into the Arctic Ocean (the other two being the Ob' and the Yenisey). With a mean annual discharge of 588 cubic kilometers per year, it is the 5th largest river globally by discharge and the second largest of the Arctic rivers (after the Yenisey)[2]. It is the largest river whose catchment is entirely within the Russian territorial boundaries. Permafrost underlies most of the catchment, with 77% of the catchment containing continuous permafrost.

Tributaries
 - left   Kirenga, Vilyuy
 - right   Vitim, Olyokma, Aldan Source   
 - location   Baikal Mountains, Irkutsk Oblast, Russia  - elevation   1,640 m (5,381 ft)
Mouth   Lena Delta 
- location   Arctic Ocean, Laptev Sea Basin   2,500,000 km2 (965,255 sq mi)

Discharge   for Laptev Sea[1]
 - average   16,871 m3/s (595,794 cu ft/s)
 - max   241,000 m3/s (8,510,835 cu ft/s)
 - min   366 m3/s (12,925 cu ft/s)


From a 2002 paper
https://stephenschneider.stanford.edu/Publications/PDF_Papers/YangEtAl2002.pdf
The long-term (1935–1999) monthly records of temperature, precipitation, stream
flow, river ice thickness, and active layer depth have been analyzed in this study to
examine Lena River hydrologic regime and recent change. Remarkable hydrologic
changes have been identified in this study. During the cold season (October–April),
significant increases (25–90%) in stream flow and decrease in river ice thickness have
been found due to warming in Siberia. In the snowmelt period (May–June), strong
warming in spring leads to an advance of snowmelt season into late May and results in a
lower daily maximum discharge in June. During summer months (July–September) the
changes in stream flow hydrology are less significant in comparison to those for winter
and spring seasons.
Title: Re: The 2018 melting season
Post by: uniquorn on May 31, 2018, 11:25:07 AM
In my opinion the Laptev gap was a bit bigger same day of year in 2007.
Agreed

imagej brightness contrast 41,255
Title: Re: The 2018 melting season
Post by: Aluminium on May 31, 2018, 12:17:16 PM
The Lena River is certainly a big beast, with a huge maximum discharge when the snow melts. June is the big month - but apparently snow-melting is also happening in May now. Presumably large amounts (200gt ?) of fresh water entering the Laptev in just one month must impact how ice loss happens in the Laptev.   See data below and images attached.

  (https://www.youtube.com/watch?v=gDridbvo3SU)
A nice video about Lena and the nature of Yakutia. The video was shot near the Lena delta at this time of year several years ago. In this video, Lena breaks ice and the ice flow begins.

In 2018, front edge of the ice flow will reach Lena delta in 3-4 days.
Title: Re: The 2018 melting season
Post by: F.Tnioli on May 31, 2018, 01:04:56 PM
Just found one interesting discovery (https://www.sciencedaily.com/releases/2018/05/180524141647.htm) about Jet Stream. Might be helpful as another little piece of the puzzle, i think.
Title: Re: The 2018 melting season
Post by: be cause on May 31, 2018, 05:55:55 PM
re the Lena delta .. it looks like flow has begun already .. the sea ice has changed colour over a 10 km area @ mid delta .. first visible 2 days ago but very clear today on worldview .. b.c.
Title: Re: The 2018 melting season
Post by: A-Team on May 31, 2018, 06:11:39 PM
As FishO noted a while back, there's noteworthy action right now on the Pacific side. The mp4 below shows the Amundsen Gulf breaking up. It shows a WorldView true color at 78 km per 100 pixels with Jaxa and Ascat insets that have considerably lesser resolution.

Tracking the velocity of one large floe coming out of the central Amundsen using the scale provided by WV yielded an average speed of 20 km/day for the last 21 days, rather a wild ride by Arctic Ocean standards.

Nasa shut down WV briefly yesterday to make some software upgrades and today their animation tool is working very well indeed. The frame number limit is 40 but doing one month at a time followed by gif concatenation in ImageJ followed by mp4 compression allows several months to be shown, though clouds can obscure motion.

The first mp4 below squeezes 31 days into 4 seconds which amounts to a 670,000-fold speed-up of ice motion. Given this rate, the ice motion appears quite fluid. It is not feasible to make comparisons to past years however.

The Amundsen has been contributing the ice all season between the Alaskan coast and the CAA Beaufort stringer. A large chunk was pinched off on April 25th by the advancing stringer and now lies to the west of the elbow. The latter's matrix of FYI is melting out, leaving the thicker floes that originated a bit north of Prince Patrick island last October.

Tech note: to make the insets in ImageJ, change canvas size to that of the larger WV taking care to set the inset's position where wanted as there is no undo. Also check 'zero fill' which sets black to transparency. Then in Paste Control, set Transfer Mode to Transparent-zero and paste the inset over the WV host image. Here there was wasted space available in lower M'Clure Strait. At the time https://www.online-convert.com/ is used, set the pixel sizes to final dimensions, say 700x700, even though forum software will force it to 720 pixel width
Title: Re: The 2018 melting season
Post by: Neven on May 31, 2018, 09:11:45 PM
I'm going to be off for a couple of days, back on Monday, not sure if I'll have WiFi there.
Title: Re: The 2018 melting season
Post by: FishOutofWater on May 31, 2018, 11:05:49 PM
Meanwhile, there are very long cracks in the Nares Strait ice and there has been movement down most of the channel visible on AQUA MODIS Worldview for May 30 and 31. You can't see movement from the Lincoln sea to the polynya, but there is clear movement in the central channel. Because the ice arch formed so late this year the ice holding it together is thin and prone to failure under strong winds.
Title: Re: The 2018 melting season
Post by: Pagophilus on May 31, 2018, 11:13:04 PM
What a river -- thanks for posting this.  It is huge at maximum discharge -- the rough equivalent of the Amazon!  And it amazing how variable it is ... its flow at maximum is about 650 times greater than its minimum discharge rate -- the Mississippi's differential is a factor of about 25).    And the graph you post shows that the discharge increases about ten fold between May and June.

So an attempt to parse this out for myself -- a huge, ongoing inrush of fresh water is about the arrive in the Laptev Sea.   The lateral freshwater plume in the Laptev is probably going to be enormous by late June, floating perkily on top of salty waters (the Amazon's freshwater plume -- maybe an unfair comparison -- extends hundreds of km into the Atlantic).  So how much warmer are the Lena's waters than those in the Laptev Sea?  Do they warm a lot as they flow through Siberia in late June and July?  And does the Lena and its plume play a significant role in the formation of the Laptev bite?

     

The Lena River is certainly a big beast, with a huge maximum discharge when the snow melts. June is the big month - but apparently snow-melting is also happening in May now. Presumably large amounts (200gt ?) of fresh water entering the Laptev in just one month must impact how ice loss happens in the Laptev. 

From Wikipedia:-
With a mean annual discharge of 588 cubic kilometers per year, it is the 5th largest river globally by discharge and the second largest of the Arctic rivers[/i] (after the Yenisey)[2]. It is the largest river whose catchment is entirely within the Russian territorial boundaries. Permafrost underlies most of the catchment, with 77% of the catchment containing continuous permafrost.

Discharge   [/b]for Laptev Sea[1]
 - average   16,871 m3/s (595,794 cu ft/s)
 - max   241,000 m3/s (8,510,835 cu ft/s)[/b]
 - min   366 m3/s (12,925 cu ft/s)


From a 2002 paper [/b]https://stephenschneider.stanford.edu/Publications/PDF_Papers/YangEtAl2002.pdf
 Remarkable hydrologic
changes have been identified in this study. During the cold season (October–April),
significant increases (25–90%) in stream flow and decrease in river ice thickness have
been found due to warming in Siberia. In the snowmelt period (May–June), strong
warming in spring leads to an advance of snowmelt season into late May and results in a
lower daily maximum discharge in June.
[/quote]
Title: Re: The 2018 melting season
Post by: epiphyte on June 01, 2018, 07:30:48 AM

Permafrost underlies most of the catchment, with 77% of the catchment containing continuous permafrost.


So what happens to the river when the permafrost starts to melt? Dramatic increase in outflow?
additional fresh water influx accelerating arctic melt through warming, or retarding it due to desalination? Sinkholes appearing from nowhere, filling, and eroding into a string of new lakes? Silt efflux lowering the albedo or increased flooding + winter freezing raising it?

To mix a metaphor,  the further we tumble down the rabbit hole, the more we are moving into uncharted territory. 
Title: Re: The 2018 melting season
Post by: uniquorn on June 01, 2018, 10:38:15 AM
Thanks for all the information about the Lena. I had a look this morning and the ice in the bay to the east is looking blue after this warm spell.
Title: Re: The 2018 melting season
Post by: gerontocrat on June 01, 2018, 11:37:03 AM
And don't forget the Yenesei (even bigger than the Lena) flowing into the Kara with the same flow profile as the Lena, the Ob (a bit smaller) with a more spread out flow, and Canada's Mackenzie, N. America's largest source of fresh water for the Arctic.
Title: Re: The 2018 melting season
Post by: be cause on June 01, 2018, 12:27:57 PM
and today the outflow from the delta is increasing over a 20 km front .. excellent worldview visibility again as Uniquorn has shown .. the stains are clear.. grey .. mid -delta . The eastern outflow has grown considerably and darkened since yesterday . I am also enjoying watching life flowing back into the veins of the delta again .. until this year my download speeds were so poor that I could rarely even open Worldview never mind enjoy it's daily gifts ! Happy melting season :) b.c.
Title: Re: The 2018 melting season
Post by: uniquorn on June 01, 2018, 12:56:30 PM
Mackenzie bay, may29-31.
Worldview Terra/modis corrected reflectance(bands 7-2-1) false colour used here to accentuate melt. Fast moving floes highlighted by A-team visible in the bay

Technical note:  terra/modis corrected reflectance(bands7-2-1)
This combination is most useful for distinguishing burn scars from naturally low vegetation or bare soil and enhancing floods. This combination can also be used to distinguish snow and ice from clouds. Snow and ice are very reflective in the visible part of the spectrum (Band 1), and absorbent in Bands 2 (near infrared) and 7 (short-wave infrared, or SWIR). Thick ice and snow appear vivid sky blue, while small ice crystals in high-level clouds will also appear blueish, and water clouds will appear white.

Water
Liquid water on the ground appears very dark since it absorbs in the red and the SWIR. Sediments in water appear dark blue. Ice and snow appear as bright turquoise. Clouds comprised of small water droplets scatter light equally in both the visible and the SWIR and will appear white. These clouds are usually lower to the ground and warmer. High and cold clouds are comprised of ice crystals and will appear turquoise.

https://tinyurl.com/y7c42h8h
Title: Re: The 2018 melting season
Post by: numerobis on June 01, 2018, 02:49:33 PM
There was no rudeness.

I’ve not been on snow at 85 F, but I have at 80 F (27 C). Some warm front popped up from somewhere and drove a huge amount of heat quite far north of Montreal. Snow isn’t that powerful that it can soak up imported heat quickly. What it can do is prevent heat from building up locally via its albedo effect.
Title: Re: The 2018 melting season
Post by: bbr2314 on June 01, 2018, 07:18:34 PM
There was no rudeness.

I’ve not been on snow at 85 F, but I have at 80 F (27 C). Some warm front popped up from somewhere and drove a huge amount of heat quite far north of Montreal. Snow isn’t that powerful that it can soak up imported heat quickly. What it can do is prevent heat from building up locally via its albedo effect.
He admitted it was rude. It is a moot point since he apologized. Why bring it up again with a meaningless anecdote? The equivalent of a senator flinging a snowball in Congress to disprove AGW.

In any case, the CMC wants to setup continental heat cannons depositing directly into the High Arctic by the end of its run. Important to note the CMC is much more conservative than the GFS when it comes to heat due to its superior modeling re: snowfall (both falling, and extant).

I would think that the anomalous snow extent in low latitudes actually supports the notion that we will see very deep negative 500MB anomalies across 50-60Nish areas adjacent to remaining snow/ice, which will act to fling vast quantities of heat from the mid-latitudes north into the Arctic via "blocking". June should prove a nasty month for volume, if not area and extent as well.

(https://www.tropicaltidbits.com/analysis/models/gem/2018060112/gem_z500aNorm_nhem_41.png)
Title: Re: The 2018 melting season
Post by: JayW on June 02, 2018, 11:21:29 AM
106 hour loop of Chukchi and Beaufort.  Some larger pieces in the Beaufort can be seen breaking up.  Open water in the Chukchi is slowly expanding.  It makes me wonder about the time of wind stress on the currents in the Chukchi, due to its late freeze up the last couple years combined with early breakup.


http://feeder.gina.alaska.edu/npp-gina-alaska-truecolor-images
Title: Re: The 2018 melting season
Post by: bbr2314 on June 02, 2018, 09:58:17 PM
Not to be rude but DMI is clearly on crack. The thickness comparison with HYCOM (which has seemingly improved its algorithm/data) is beyond absurd. DMI shows 2-3M ice NE of Svalbard when satellite confirms HYCOM is clearly correct. DMI also shows no Laptev bite whatsoever.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Focean.dmi.dk%2Fanim%2Fplots%2Fice.arc.121.png&hash=82d515f5b606e7dc5d7121e3032bd7f3)

(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticictn/nowcast/ictn2018053112_2018060100_930_arcticictn.001.gif)
Title: Re: The 2018 melting season
Post by: Ktb on June 02, 2018, 10:44:59 PM
The slater projection is functional once again. Predicting extent of 7.62 million kn^2 on July 22, 2018. Thanks to b.c. For prompting me to update from the meaningless thread.

I'd love to believe my nagging to University of Colorado had some impact
Title: Re: The 2018 melting season
Post by: Frivolousz21 on June 02, 2018, 11:13:17 PM
Warm air is finally pouring into the Pacific side of the Arctic basin.

We can expect the big albedo drop over essentially the entire Pacific side up to 80N within a couple days.


After day 5 the models keep flip flopping all over


The latest GFS shows a major dipole.  The euro shows the opposite.

But the euro is also a huge torch over the ESS and Laptev with nasty warmth bulleting into the Arctic on a powerful long wind fetch. 
Title: Re: The 2018 melting season
Post by: Juan C. García on June 03, 2018, 05:35:26 AM
It is interesting that according to the DMI 80°N temperature, now it is colder than normal there.
Title: Re: The 2018 melting season
Post by: meddoc on June 03, 2018, 08:15:33 AM
The slater projection is functional once again. Predicting extent of 7.62 million kn^2 on July 22, 2018. Thanks to b.c. For prompting me to update from the meaningless thread.

I'd love to believe my nagging to University of Colorado had some impact

I'd say that is a helluvan optimistic Projection by the Look of Things now.
Title: Re: The 2018 melting season
Post by: jdallen on June 03, 2018, 08:59:09 AM
It is interesting that according to the DMI 80°N temperature, now it is colder than normal there.
That graph makes utterly no sense, when the weather models are all showing *current* positive anomalies.
Title: Re: The 2018 melting season
Post by: DavidR on June 03, 2018, 09:13:03 AM
It is interesting that according to the DMI 80°N temperature, now it is colder than normal there.
That graph makes utterly no sense, when the weather models are all showing *current* positive anomalies.
It looks pretty right to me.  Climate Reanalyzer is currently showing a -0.1 anomaly across the Arctic and most of the negative area is in the plus 80N region.  By Tuesday the anomaly climbs to plus 2 and stays near that for the rest of the week. There's some very hot weather in Northern Russia and the CAB by then.
Title: Re: The 2018 melting season
Post by: gerontocrat on June 03, 2018, 10:16:01 AM
It is interesting that according to the DMI 80°N temperature, now it is colder than normal there.
That graph makes utterly no sense, when the weather models are all showing *current* positive anomalies.
Oh yes it does. That bit of the Arctic is showing negative anomalies, and the area above 80 degrees north is but a small fraction of the area of the Arctic (as defined by the Arctic circle). See below for some actual data.
Title: Re: The 2018 melting season
Post by: S.Pansa on June 03, 2018, 10:30:39 AM
Add to that the fact that the DMI-80N-temps are heavily biased to a small area around the North Pole. See for instance Rob Dekkers explanation (http://neven1.typepad.com/blog/2017/02/piomas-february-2017.html?cid=6a0133f03a1e37970b01b7c8df1d3f970b#comment-6a0133f03a1e37970b01b7c8df1d3f970b) on Nevens blog:

Quote
... because the data is not area-weighted.

For example, in the DMI temperature graph (on a 0.5 deg grid) attaches 40x the significance to the temperature within 0.5 deg of the NP as compared to the significance of a similar area at the 80 deg North lateral. And since area/distance around the NP is a quadratic function, the DMI graph is for 50% determined by the temperature between 87.5-90N, which is only 25% of the area North of 80deg.

In short: The DMI 80N temps do miss most of the Arctic action ... or is overly dramatic
Title: Re: The 2018 melting season
Post by: gerontocrat on June 03, 2018, 11:09:39 AM
Add to that the fact that the DMI-80N-temps are heavily biased to a small area around the North Pole.
Quote
... because the data is not area-weighted.

For example, in the DMI temperature graph (on a 0.5 deg grid) attaches 40x the significance to the temperature within 0.5 deg of the NP as compared to the significance of a similar area at the 80 deg North lateral. And since area/distance around the NP is a quadratic function, the DMI graph is for 50% determined by the temperature between 87.5-90N, which is only 25% of the area North of 80deg.

In short: The DMI 80N temps do miss most of the Arctic action ... or is overly dramatic
Quote
the DMI graph is for 50% determined by the temperature between 87.5-90N, which is only 25% of the area North of 80 deg.

Nope - much less

                                                                 Million Km2       Percent of 80+
Surface area above 80+ North in  million km2       3.875    
Surface area above 87.5+ North in  million km2    0.243              6.3%




Title: Re: The 2018 melting season
Post by: cesium62 on June 03, 2018, 11:32:16 AM
The slater projection is functional once again. Predicting extent of 7.62 million kn^2 on July 22, 2018. Thanks to b.c. For prompting me to update from the meaningless thread.

I'd love to believe my nagging to University of Colorado had some impact

I'd say that is a helluvan optimistic Projection by the Look of Things now.

From Charctic, the extent on the 22nd (203rd day of the year) for the past 7 years has been in a fairly tight band from 7.2 to 7.9 mk2.  2016 extent was lower than 2018 at this time of year, but hit 7.65 on the 22nd.  So the Slater projection seems plausible based on Charctic trend lines.  On the other hand, the Kara typically loses 3/4ths of its ice by late July, and the Slater projection kind of shows it full of ice then.  And the Hudson typically loses 5/6ths of its ice by the time the Slater projection suggests it losing around half of its ice... 
Title: Re: The 2018 melting season
Post by: romett1 on June 03, 2018, 11:44:58 AM
Speaking about Lena River Delta, then quite high temperatures (+25.3 °C) forecasted for Wednesday.
Title: Re: The 2018 melting season
Post by: Alexander555 on June 03, 2018, 11:52:12 AM
What am i missing ? The first 2 pics are from yesterday. The 3th is for 22 July. There shoud be a 4,5 million square km gap.
Title: Re: The 2018 melting season
Post by: Steven on June 03, 2018, 12:19:01 PM
Quote
because the data is not area-weighted... the DMI graph is for 50% determined by the temperature between 87.5-90N, which is only 25% of the area North of 80deg.

He probably meant 85-90N:

the DMI graph is for 50% determined by the temperature between 85-90N, which is only 25% of the area North of 80deg.
Title: Re: The 2018 melting season
Post by: JayW on June 03, 2018, 12:23:01 PM
What am i missing ? The first 2 pics are from yesterday. The 3th is for 22 July. There shoud be a 4,5 million square km gap.

It's a purely statistical "forecast".  Areas that have a positive extent anomaly currently will be "assumed" by the model to persist. 

Perhaps the late Dr. Slater's post explains it.  I couldn't quote the original post. Linked here https://forum.arctic-sea-ice.net/index.php/topic,778.msg28212.html#msg28212

Quote
Persistence (light blue line) in the time series plot is an anomaly persistence. At the issue date (d), compute the difference of the observation from the long term mean for that day of year; this is the anomaly. At the forecast date (d+lead_time), find the long term mean and add the previously computed anomaly i.e. you have persisted the anomaly.
The "Forecast" is the method based on regression and integrating the probability of ice survival etc.
Persistence is on the plot in response to a comment that the Forecast provides no added value compared to persistence, but this can't be judged from just one year. My brief bits of work suggest it is non-trivial to beat persistence at sub-seasonal timescales.

The plots on the page should update every day - it's only a 50-day forecast (though I have run longer cases).  I haven't got around to adding conf. intervals ...
Title: Re: The 2018 melting season
Post by: Alexander555 on June 03, 2018, 12:43:32 PM
It's a 3,5 million square km gap. But the 3th pic looks a lot like the first one. The surface that is covered is the same, and still they are talking about 7,7 million km2 and almost 11 million km2. Some magic.
Title: Re: The 2018 melting season
Post by: uniquorn on June 03, 2018, 12:54:20 PM
The  kolyma river that runs into the ESS already had some warmer weather recently. Worldview may29 and jun3.

terra/modis true color images adjusted using imagej brightness/contrast 41,256
Title: Re: The 2018 melting season
Post by: Koop in VA on June 03, 2018, 01:11:10 PM
It's a 3,5 million square km gap. But the 3th pic looks a lot like the first one. The surface that is covered is the same, and still they are talking about 7,7 million km2 and almost 11 million km2. Some magic.

I agree with you and therefore share your confusion.  Let's just focus on one area, the Hudson.  Based on recent historical extent numbers, by July 22 we would expect approximately 80% of the extent to melt out.  On the Slater projection there is very little detectable extent reduction.  So I'm not sure how that is an accurate representation of what the extent will be in 7 weeks.
Title: Re: The 2018 melting season
Post by: uniquorn on June 03, 2018, 01:33:37 PM
The slater projection is functional once again. Predicting extent of 7.62 million kn^2 on July 22, 2018. Thanks to b.c. For prompting me to update from the meaningless thread.

I'd love to believe my nagging to University of Colorado had some impact
Maybe they posted that image without checking that it updated. Can you send another message?
Title: Re: The 2018 melting season
Post by: gerontocrat on June 03, 2018, 02:19:38 PM
It's a 3,5 million square km gap. But the 3th pic looks a lot like the first one. The surface that is covered is the same, and still they are talking about 7,7 million km2 and almost 11 million km2. Some magic.

I agree with you and therefore share your confusion.  Let's just focus on one area, the Hudson.  Based on recent historical extent numbers, by July 22 we would expect approximately 80% of the extent to melt out.  On the Slater projection there is very little detectable extent reduction.  So I'm not sure how that is an accurate representation of what the extent will be in 7 weeks.

I am also convinced that the pretty picture is NOT the forecast extent / thickness.

It is the sort of thing that happens when an old package is dug out of the cupboard (as I know to my discomfort).
Title: Re: The 2018 melting season
Post by: gerontocrat on June 03, 2018, 03:18:00 PM
I like pretty pictures - here are two.
Concentration maps from NSIDC and University of Bremen.

My old eyes actually find the NSIDC one easier to look at. Central Arctic is looking a bit shaky?

One needs to click on them to see them properly, and then click on them again to see them in full size
Title: Re: The 2018 melting season
Post by: Telihod on June 03, 2018, 07:05:12 PM
Speaking about Lena River Delta, then quite high temperatures (+25.3 °C) forecasted for Wednesday.
The temperature anomaly forecast for thursday looks insane. 15-20 C above normal in some parts of Siberia.
Title: Re: The 2018 melting season
Post by: bbr2314 on June 03, 2018, 07:21:44 PM
If the GFS is anywhere close to correct there will be widespread 80-90F+ temperatures beginning over Siberia starting today/tomorrow. By D4-5-6 the 90s are becoming widespread. And the heat is dumping into the Arctic, with 50F readings and rain occurring over the Siberian-adjacent seas and CAB...!

(https://www.tropicaltidbits.com/analysis/models/gfs/2018060312/gfs_T2m_nhem_24.png)

(https://www.tropicaltidbits.com/analysis/models/gfs/2018060312/gfs_T2m_nhem_28.png)

The conservative Canadian shows something similar (but less dramatic).

(https://www.tropicaltidbits.com/analysis/models/gem/2018060312/gem_T2ma_nhem_18.png)

(https://www.tropicaltidbits.com/analysis/models/gem/2018060312/gem_T2m_nhem_32.png)

Title: Re: The 2018 melting season
Post by: Richard Rathbone on June 03, 2018, 07:32:27 PM
What am i missing ? The first 2 pics are from yesterday. The 3th is for 22 July. There shoud be a 4,5 million square km gap.

They are pictures of different things. One is concentration, the other is probability of extent. Crudely approximating the Slater model says it takes about 50 days to melt out once ice concentration is reliably below 100%. Consequently ice concentration now looks very similar to the model's extent probability in 50 days time during the melt season.
Title: Re: The 2018 melting season
Post by: bbr2314 on June 03, 2018, 07:35:12 PM
What am i missing ? The first 2 pics are from yesterday. The 3th is for 22 July. There shoud be a 4,5 million square km gap.

They are pictures of different things. One is concentration, the other is probability of extent. Crudely approximating the Slater model says it takes about 50 days to melt out once ice concentration is reliably below 100%. Consequently ice concentration now looks very similar to the model's extent probability in 50 days time during the melt season.

It looks like the model is having problems with the Atlantic front as it shows two "fronts" to the ice. I believe this is because the current situation N of Svalbard is unprecedented / therefore it predicts ice where it already isn't even 50 days ahead (you can see this on the map). I would assume it will have the same issues with the Pacific front, where it shows no losses through the end of July...
Title: Re: The 2018 melting season
Post by: Pagophilus on June 03, 2018, 09:28:26 PM
Thanks, Telihod, bbr.  That mad hot section of Siberia on your forecast post is pretty much the catchment of the Lena River.   Here is some more on the Lena River – yes, I got a bit obsessed, but what with the forecast for the catchment area being what it is, and the maximum period of discharge of the Lena launching right now, the following might be of direct interest. 

I found a fine and relevant paper on-line (Baozhong Liu & Daqing Yang, 2011).    The study, published in 2011, mainly cites 1950-1990 information, but it is probably safe to assume trends have continued or accelerated.  Three takeaways:  Discharge in June has been (i) increasing over time (ii) the flood discharge is beginning earlier in the year and (iii) the average temperature of the water is increasing.  A triple-whammy for Arctic ice. 

June waters are the highest volume by far and averaged just under 3 C for the study period (see the excellent graphs from the paper below).  The actual heat flow of the Lena rises somewhat in June, but the waters are so cool then, that heat flow is actually at its greatest in July and August, when the river is much warmer (ca 13 C and upwards ). 

An increase of heat flow of ca. 40% was observed for June over the 1950-1990 study period, with much lower heat flow increases in July and August.   The Lena is estimated to provide 5-10% of the yearly heat flow into the Laptev Sea.   Roughly extrapolating the trends from the study, then the Lena could be pouring up to about 80% or perhaps considerably more heat into the Laptev during June than it was in 1950, and it is doing so earlier.

A few additional thoughts, some on the comforting side.   The size of the Lena delta is not discussed as a factor in the article.  Data were measured before the river arrives at the delta and then splits into innumerable small channels.  The Lena delta is really big … about 100 km long and 400 km wide.  So it strikes me that it may well take much of the water a while to meander and slowly flood through the delta itself, making its arrival in the Laptev maybe a few days after the discharge station dates, actually arriving on June 5, say, rather than on June 1.  I don’t know if any correction for this factor is made in most studies. 

Also, the river cools as it flows north, so the temperatures at the discharge stations may be higher than the temperatures of that 400 km wide flood that actually enters the Laptev.  Evaporative losses in particular may cool such a huge sheet of water flowing through the delta.

 The paper can be accessed at https://iahs.info/uploads/dms/16848.16-71-76-346-29_Baozhong_Liu-H02Corr.pdf     I have also thrown in a false color mostly IR Satellite photo of the Lena delta from Wikipedia, in part because it is so beautiful. 


If the GFS is anywhere close to correct there will be widespread 80-90F+ temperatures beginning over Siberia starting today/tomorrow. By D4-5-6 the 90s are becoming widespread. And the heat is dumping into the Arctic, with 50F readings and rain occurring over the Siberian-adjacent seas and CAB...!
Title: Re: The 2018 melting season
Post by: Pagophilus on June 03, 2018, 11:26:50 PM
Aluminium, I really appreciated this beautiful, evocative video ... it allowed me to layer some reality on all the data.  Thanks!


A nice video about Lena and the nature of Yakutia. The video was shot near the Lena delta at this time of year several years ago. In this video, Lena breaks ice and the ice flow begins.

In 2018, front edge of the ice flow will reach Lena delta in 3-4 days.
Title: Re: The 2018 melting season
Post by: Nikita on June 03, 2018, 11:59:27 PM
...
Title: Re: The 2018 melting season
Post by: numerobis on June 04, 2018, 12:17:24 AM
That's one of the Svalbard hot spots (you can see the other). They're always there; there seems to be some debate about whether they're real.

https://forum.arctic-sea-ice.net/index.php?topic=2194.0
Title: Re: The 2018 melting season
Post by: uniquorn on June 04, 2018, 12:24:43 AM
The Lena Delta looks very warm but I think the Kara Sea will be feeling the heat more than the Laptev on Wednesday if the forecasts are correct. (edit:saturday might be a different story..)
Despite cooler weather ice in the east Kara/Barents is already very mobile.

windy.com ecmwf and gfs temperature forecasts for wed jun6
Title: Re: The 2018 melting season
Post by: bbr2314 on June 04, 2018, 06:26:03 AM
First GAC of the season? The ATL front is about to get... quite a wallop. GFS upped ante and heat at 00z.

(https://www.tropicaltidbits.com/analysis/models/gfs/2018060400/gfs_mslpaNorm_nhem_14.png)

(https://www.tropicaltidbits.com/analysis/models/gfs/2018060400/gfs_T2m_nhem_14.png)

Title: Re: The 2018 melting season
Post by: aperson on June 04, 2018, 06:33:28 AM
First GAC of the season? The ATL front is about to get... quite a wallop. GFS upped ante and heat at 00z.

(https://www.tropicaltidbits.com/analysis/models/gfs/2018060400/gfs_mslpaNorm_nhem_14.png)

~60mb pressure gradient and a closed circulation all the way up to the 200mb level. Yikes, I'm definitely staying up for the 00z ECMWF tonight to see its take.


Edit: You may also want to download and reupload those analysis images since they will break once it cycles out of TropicalTidbits range (I think they store the last month's of runs).
Title: Re: The 2018 melting season
Post by: bbr2314 on June 04, 2018, 06:37:46 AM
Eh. We'll have the satellite data soon enough!

CMC agrees with GFS, which means we should be "game on" since it is way more reasonable re: heat. And even then, it is an absolute torch.

(https://www.tropicaltidbits.com/analysis/models/gem/2018060400/gem_mslpaNorm_nhem_13.png)

(https://www.tropicaltidbits.com/analysis/models/gem/2018060400/gem_T2ma_nhem_14.png)
Title: Re: The 2018 melting season
Post by: bbr2314 on June 04, 2018, 06:43:58 AM
Continental heat pulses becoming increasingly extreme, people already dying en-masse in Pakistan and we haven't even hit the beginning of the 50C+ readings which will be widespread and worsening by D3-4. This is going to have some impact on the Arctic as the extant snowcover in northern Siberia and the Himalayas act as enormous cannons/anchors for negative 500MB anomalies & LP, firing heat surges north into the Siberian Seas and CAB (as we see in ^^^ output).

(https://www.tropicaltidbits.com/analysis/models/gfs/2018060400/gfs_T2m_india_15.png)

YIKES!

(https://www.tropicaltidbits.com/analysis/models/gfs/2018060400/gfs_T2ma_nhem_23.png)
Title: Re: The 2018 melting season
Post by: jdallen on June 04, 2018, 07:29:37 AM
Eh. We'll have the satellite data soon enough!

CMC agrees with GFS, which means we should be "game on" since it is way more reasonable re: heat. And even then, it is an absolute torch.

<SNIPPAGE>

Looking at Climate Reanalyzer checking snow cover and pressure, you can see the low forming up in the western Kara in about 36 hours.  Over the next 96 hours or so, it looks like the weather will absolutely crush any remaining Eurasian snow cover and seriously smash snow cover on the Arctic pack.

That's about as far as I'd trust the forecast trend, but at hour 96 it does like we have a pretty good dipole set up running from the Laptev/Eastern Kara towards the eastern CAA, with a pressure differential of about 48MB (1026 vs 978).

At 72 hours as shown we have 15-20C+ anomalies predicted for most of the Siberian coast all the way Scandinavia.  Also visible indirectly is the huge "wheel" of the air masses with warmer air rotating into the Arctic from central Siberia and the colder Arctic air being driven into eastern Europe.

If the models follow what actually happens, but the time we get 6 days out, Northern hemisphere snow cover will be reduced by over 70%, and snow cover on the pack by over half.

Look for extensive melt ponding everywhere outside of the area directly north of Greenland by June 10th if this plays out.
Title: Re: The 2018 melting season
Post by: jdallen on June 04, 2018, 07:38:44 AM
I'll take the liberty here to add the current 12Z estimated snow cover/air pressure and what it's estimated to be in 72 hours.
Title: Re: The 2018 melting season
Post by: meddoc on June 04, 2018, 07:49:53 AM
Continental heat pulses becoming increasingly extreme, people already dying en-masse in Pakistan and we haven't even hit the beginning of the 50C+ readings which will be widespread and worsening by D3-4. This is going to have some impact on the Arctic as the extant snowcover in northern Siberia and the Himalayas act as enormous cannons/anchors for negative 500MB anomalies & LP, firing heat surges north into the Siberian Seas and CAB (as we see in ^^^ output).

India & Pakistan both Nuclear Powers. Sharing the Himalayan Freshwater Reserves with- You guessed it- Nuclear Power China....
Title: Re: The 2018 melting season
Post by: Alexander555 on June 04, 2018, 07:56:33 AM


~60mb pressure gradient and a closed circulation all the way up to the 200mb level. Yikes, I'm definitely staying up for the 00z ECMWF tonight to see its take.


Aperson or bbr2314, if you would have time. Is it possible to describe the things you are talking about in other words. And what the impact is.
Title: Re: The 2018 melting season
Post by: bbr2314 on June 04, 2018, 09:12:38 AM


~60mb pressure gradient and a closed circulation all the way up to the 200mb level. Yikes, I'm definitely staying up for the 00z ECMWF tonight to see its take.


Aperson or bbr2314, if you would have time. Is it possible to describe the things you are talking about in other words. And what the impact is.
The impact of this would be sustained days of 100K+ losses (IMO). EURO follows GFS.

(https://www.tropicaltidbits.com/analysis/models/ecmwf/2018060400/ecmwf_z500_mslp_nhem_5.png)

(https://www.tropicaltidbits.com/analysis/models/ecmwf/2018060400/ecmwf_T850a_nhem_5.png)
Title: Re: The 2018 melting season
Post by: bbr2314 on June 04, 2018, 09:14:56 AM
I'll take the liberty here to add the current 12Z estimated snow cover/air pressure and what it's estimated to be in 72 hours.
It looks like the GFS is initializing incorrectly because MODIS shows much more extensive snowpack over Quebec vs. the estimated cover. This is not surprising because the GFS is terrible at snowpack . Losses will be impressive over the next week but the GFS is probably overdone (and more importantly, it appears to start out UNDERdone).
Title: Re: The 2018 melting season
Post by: aperson on June 04, 2018, 09:21:12 AM


~60mb pressure gradient and a closed circulation all the way up to the 200mb level. Yikes, I'm definitely staying up for the 00z ECMWF tonight to see its take.


Aperson or bbr2314, if you would have time. Is it possible to describe the things you are talking about in other words. And what the impact is.

In the Sea Level Pressure charts posted above, the pressure difference from high pressure (~1025) to low pressure (~965) is around 60 millibars.

In these graphs you will see isobars of equal pressure drawn around the high pressure and low pressure centers. The tighter these isobars are, the faster wind flows along them. In the northern hemisphere, low pressure rotates counter-clockwise, and high pressure rotates clockwise, so this should let you figure out the direction of the wind.

The wind that flows along the isobar contours of constant pressure is known as geostrophic wind. See this for reference: http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/geos.rxml

From this exercise, you can work out how strong wind is blowing and where it is bringing air from just by looking at the Sea Level Pressure charts. This lets us figure out that lots of heat is being brought in from the midlatitudes with strong winds in the charts posted above.
Title: Re: The 2018 melting season
Post by: FredBear on June 04, 2018, 12:30:47 PM
Re: Reply #954
The 2m 0°C isotherm (orange line) probably limits precipitation to snow (not rain) even where any warmth tries to go into the Arctic? New snow will protect any ice it falls on until it becomes "old snow" and loses it's albedo - which may not be long these days!
Title: Re: The 2018 melting season
Post by: uniquorn on June 04, 2018, 01:44:12 PM
With Kara and Barents first in the firing line, here is amsr2 uni-hamburg concentration map for the melting season mar21-jun3.
Eastern Kara/Barents have been mobile all season with some refreeze between older floes. This younger ice will not last long in strong warm winds if the forecast plays out.
Title: Re: The 2018 melting season
Post by: F.Tnioli on June 04, 2018, 02:51:03 PM
...
At 72 hours as shown we have 15-20C+ anomalies predicted for most of the Siberian coast all the way Scandinavia.  Also visible indirectly is the huge "wheel" of the air masses with warmer air rotating into the Arctic from central Siberia and the colder Arctic air being driven into eastern Europe.

If the models follow what actually happens, but the time we get 6 days out, Northern hemisphere snow cover will be reduced by over 70%, and snow cover on the pack by over half.
...
It's been my understanding that such a "wheel" is one of required circumstances for Blue Arctic event (among few others), having it happening exactly this time of the year (late May / early June) and persisting, with possible short slowdowns, for over a month. One can perhaps call it "GJB" - "Great Jetstream Breach", akin to how we routinely say "GAC" about big arctic cyclones now. AFAICT, GJBs will be inceasingly strong and frequent as seasons go by.

Not only it will quickly remove snow cover and melt/rain pond much of ice, but it also significantly increase current athmosperic energy content in NH, since all the cold air transferred to eastern Europe and such - will lose less energy nighttime than normal-temperature-there air, and similarly accumulate more energy during daytime (Stefan-Boltzman law), while 24/7 or nearly 24/7 sunlight in Arctic will make sure there is no "increasd" heat loss there during nighttime (since there is none, at the time).

So my question is: what you gentlemen think, by now - how long this "wheel", this cross-Jetstream air mass ~circular current of continental proportions, could persist if it will form exactly as forecasted?
Title: Re: The 2018 melting season
Post by: Pagophilus on June 04, 2018, 05:13:25 PM
That storm looks like it will hit all that fragmented ice in the north Kara Sea between Fran Josef Land and the Russian coast, so the effect is likely to be considerable -- buffeting floes, smashing thinner refrozen ice, generating large waves etc (as opposed to those high winds sweeping over continuous ice cap without penetrating it and thereby not causing waves).

First GAC of the season? The ATL front is about to get... quite a wallop. GFS upped ante and heat at 00z.

Title: Re: The 2018 melting season
Post by: bbr2314 on June 04, 2018, 05:27:45 PM

Strongly agree. It also looks like it will eventually bring rain across the Siberian Seas through to the Chukchi. The combination is likely to deliver a critical blow at a time when melt ponding & retaining extant albedo is absolutely most critical (this event will come close to coinciding with solstice, which is extremely early / earliest ever in the season (?) I can recall a storm like this?
Title: Re: The 2018 melting season
Post by: jdallen on June 04, 2018, 07:04:03 PM
Re: Reply #954
The 2m 0°C isotherm (orange line) probably limits precipitation to snow (not rain) even where any warmth tries to go into the Arctic? New snow will protect any ice it falls on until it becomes "old snow" and loses it's albedo - which may not be long these days!
Not sure that will be the case here Fred.  I expect there will be higher temperatures aloft, and the h2o will be carried as moisture or vapor, not ice crystals.

The net heat budget should be generally positive, which should prevent snow except at the highest latitudes.
Title: Re: The 2018 melting season
Post by: jdallen on June 04, 2018, 08:15:38 PM

Strongly agree. It also looks like it will eventually bring rain across the Siberian Seas through to the Chukchi. The combinateion is likely to deliver a critical blow at a time when melt ponding & retaining extant albedo is absolutely most critical (this event will come close to coinciding with solstice, which is extremely early / earliest ever in the season (?) I can recall a storm like this?
What happens on the Pacific side is a concern as well, as all the models are in pretty close agreement out to 72 hours.  Besides the storm which will wreck the Kara and Barents to start, we have persistent hiigh pressure from the Laptev to the CAA.

Other things to note - the string of systems, high and low, along the eastern north American/Atlantic margin which will tend to continue shoving heat north, similar setup along the rockies, and the dipole set up to torch the eastern Kara/western Laptev.

Hard to find good news there, especially within the 72 hour envelope descibed.
Title: Re: The 2018 melting season
Post by: Greenbelt on June 04, 2018, 08:38:04 PM
Worldview shows the developing cyclone
(https://gibs.earthdata.nasa.gov/image-download?TIME=2018155&extent=1215488,350208,2495488,1382400&epsg=3413&layers=MODIS_Terra_CorrectedReflectance_TrueColor,Coastlines&opacities=1,1&worldfile=false&format=image/jpeg&width=1250&height=1008)
Title: Re: The 2018 melting season
Post by: A-Team on June 04, 2018, 09:19:15 PM
What is left in the Chukchi and Wrangel is in worse shape in post-normalized visible than it appears in synoptic radars. The browning could be air pollution from Asia, smoke from wildfires, dust from the Taklamakan desert, algal surface growth, or embedded particulate deposits in snow being concentrated by melt and so on. It has been around for several days with today being the worst.

The area has been mostly cloud-free so the browning has been contributing to sunlight heat retention whether still airborne or on the surface of the ice. However it is only one of several forcings currently underway.

The image below displays at larger size with a click or view interactively at Nasa Worldview, save image and linearly adjust contrast.

 https://tinyurl.com/yctb26xn
Title: Re: The 2018 melting season
Post by: marcel_g on June 04, 2018, 09:24:13 PM
...
YIKES!
...

Well, this is certainly one of those Holy Shit predictions that make this thread impossible to put down. For me anyway.


After this melt season has kind of muddled along, and I was thinking there might be a chance that it could get cloudy just in time for June and stave off the melt ponds and solar absorption.

But looking at those images, and climate reanalyzer and it seems that the only positive in the next few days is going to be that the arctic won't be completely sunny, but that is a lot of heat and moisture plowing all the way across the entire CAB.

If the sun comes out afterwards, then wow.
Title: Re: The 2018 melting season
Post by: Lord M Vader on June 04, 2018, 09:34:43 PM
The latest operational EC 12z forecast is completely brutal for the sea ice! Expect an onslaught in Kara-Barents Sea followed by high pressure centered in the CAB and Beaufort! The only thing that would be worse is a dipole setting up over the Arctic. No such is in sight at this moment.
Title: Re: The 2018 melting season
Post by: uniquorn on June 04, 2018, 10:03:52 PM
With the warm pulse continuing on the Pacific side, ECMWF WAM forecasts 2m waves in the Chukchi from Thurs to Sat. Clearer weather today and in 2017 gives an opportunity to compare the state of the ice over the 2 years.
Although melting at similar rates so far, with 2018 slightly ahead (2017 in orange on Wipneus chart), probably due to the early melt in the Bering Sea, there is a distinct lack of large floes this year, and the current weather suggests that melt will keep pace with 2017 over the next week or so.
The animation takes a broad view of the Chukchi, then zooms in on 3 areas, showing 2017 first in each case.
Looking at it again, 2018 ice does look browner than 2017.

tech note:
all worldview images filtered using imagej unsharp mask 1,0.5
Title: Re: The 2018 melting season
Post by: jdallen on June 04, 2018, 10:22:50 PM
The latest operational EC 12z forecast is completely brutal for the sea ice! Expect an onslaught in Kara-Barents Sea followed by high pressure centered in the CAB and Beaufort! The only thing that would be worse is a dipole setting up over the Arctic. No such is in sight at this moment.
Take a look at the 12Z run at around or about +72 hours.  That looks awful dipole-ish.
Title: Re: The 2018 melting season
Post by: jdallen on June 04, 2018, 10:27:07 PM
What is left in the Chukchi and Wrangel is in worse shape in post-normalized visible than it appears in synoptic radars.
<snippage>

With high pressure, sunlight and above freezing temperatures, like 4-6CM of top melt a day worse.

Most of that ice sans relict MYI was 1.75M or under, IIRC.

I'd say most of that ice will be gone by the end of the month.  The albedo is way to low.
Title: Re: The 2018 melting season
Post by: Hyperion on June 04, 2018, 11:32:57 PM
Meanwhile on the oceanic heat front, Mr Atlantic seems to have hit the nitrous. We have a very coherent and rapid Gulfstream flow hitting speeds near five thousand km per month. I've not before seen its like. Could be the start of a much feared but rarely mentioned superfast Gulfstream pulse that some scientists claim to have identified in the paleo record associated with major melt pulses coming out of the ice ages. Maybe there will be no Arctic winter this year.
Title: Re: The 2018 melting season
Post by: numerobis on June 05, 2018, 12:27:05 AM
http://nunatsiaq.com/stories/article/65674cold_spring_breaks_records_in_nunavik_nunavut/

As we saw it was a cold May in Nunavut, Nunavik, and Nunatsiavut (but not Inuvialiut). Kuujjuaq was almost 6C below normal; Iqaluit 3C; Rankin 3.6C below norm.
Title: Re: The 2018 melting season
Post by: jdallen on June 05, 2018, 12:32:09 AM
Meanwhile on the oceanic heat front, Mr Atlantic seems to have hit the nitrous. We have a very coherent and rapid Gulfstream flow hitting speeds near five thousand km per month<snippage>. Maybe there will be no Arctic winter this year.
A bit soon for that speculation, but the idea of a big pulse of "hot" Atlantic water arriving at the doorstep of the CAB at the end of July is unsettling. 

By then, the Kara and Barents ice should be gone, so it's immediate effect will depend on what ice gets swept over it by circulation, or how much heat gets into the basin proper and applied to the ice.

The bigger question will be what it does to the end of the melt season, if it extends it, and how much the weather is affected.
Title: Re: The 2018 melting season
Post by: Aluminium on June 05, 2018, 02:42:40 AM
Forecast from earth.nullschool.net for 07.06.2018 09:00 UTC. There are winds up to 72 km/h, total precipitable water over 25 kg/m2, T850 about 10°C.
Title: Re: The 2018 melting season
Post by: FishOutofWater on June 05, 2018, 05:58:10 AM
The Florida current cable shows the Gulf Stream moving right along for the past 6 weeks, but it's moving on the high side of the normal range. There's definitely a strong sea surface height gradient across the subpolar gyre so that part of the Gulf Stream system will be kicking into overdrive. There has been a stunning amount of poleward heat transfer by the atmosphere over the north Atlantic for the past 6 weeks.
Title: Re: The 2018 melting season
Post by: bbr2314 on June 05, 2018, 06:00:00 AM
The Florida current cable shows the Gulf Stream moving right along for the past 6 weeks, but it's moving on the high side of the normal range. There's definitely a strong sea surface height gradient across the subpolar gyre so that part of the Gulf Stream system will be kicking into overdrive. There has been a stunning amount of poleward heat transfer by the atmosphere over the north Atlantic for the past 6 weeks.
And it is only going to continue. SSTs should be warming dramatically over the far NATL for the foreseeable future. This year is truly going to torch.

More immediately, the 00z GFS ups the ante on the first GAC.

(https://www.tropicaltidbits.com/analysis/models/gfs/2018060500/gfs_z500_mslp_nhem_10.png)
Title: Re: The 2018 melting season
Post by: bbr2314 on June 05, 2018, 06:14:48 AM
Consensus continues to deepen, Canucks join GFS.

(https://www.tropicaltidbits.com/analysis/models/gem/2018060500/gem_mslpaNorm_nhem_10.png)

CAB rainy heatwave extending across all Siberian Seas

(https://www.tropicaltidbits.com/analysis/models/gem/2018060500/gem_T2m_nhem_17.png)

(https://www.tropicaltidbits.com/analysis/models/gfs/2018060500/gfs_T2m_nhem_17.png)

There looks to be a lot of very fragile ice in the path of the upcoming event. The melt ponding on the areas that aren't will be severe. Will we see a cliff of several 100-200K daily losses?

(https://www.tropicaltidbits.com/analysis/models/gfs/2018060500/gfs_T2ma_nhem_16.png)
Title: Re: The 2018 melting season
Post by: aperson on June 05, 2018, 06:33:51 AM
00z GFS Animation 0h - 168h of the possible trajectory of the possible GAC: https://i.imgur.com/91lX6aH.mp4
Title: Re: The 2018 melting season
Post by: jdallen on June 05, 2018, 07:22:02 AM
00z GFS Animation 0h - 168h of the possible trajectory of the possible GAC: ...
If it happens it will be like pulling a zipper across the central basin.
Title: Re: The 2018 melting season
Post by: meddoc on June 05, 2018, 08:35:34 AM
00z GFS Animation 0h - 168h of the possible trajectory of the possible GAC: ...
If it happens it will be like pulling a zipper across the central basin.

Hycom shows a huge crack starting from the Atlantic Front into the Direction of NP
Title: Re: The 2018 melting season
Post by: aperson on June 05, 2018, 08:53:17 AM
I've been looking for a quick way to validate temperatures from models across the Arctic. VIIRS Brightness Temperature (Band I5, Day) and Night overlays seem to work pretty well. In tandem with using Terra / MODIS Bands 7-2-1 to locate clouds, one can look at the surface temperatures where there are no clouds.

Here is June 4th with the day band overlayed. The lowest shaded bucket is 270.9-271.6K (-2.25C - -1.55C). Above freezing temps occur at the transition to purple and max out at 4.05C.

(https://i.imgur.com/Ai5kMi8.jpg)
(https://i.imgur.com/Ai5kMi8.jpg)

Here is a link to Worldview which has this overlay specified for VIIRS day and night bands: https://worldview.earthdata.nasa.gov/?p=arctic&l=MODIS_Terra_CorrectedReflectance_Bands721,VIIRS_SNPP_CorrectedReflectance_TrueColor,MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor(hidden),Coastlines,VIIRS_SNPP_Brightness_Temp_BandI5_Day(opacity=0.67,palette=rainbow_1,min=270.9,271.6,max=276.6,277.2,squash),VIIRS_SNPP_Brightness_Temp_BandI5_Night(hidden,opacity=0.67,palette=rainbow_1,min=270.9,271.6,max=276.6,277.2,squash)&t=2018-06-04-T00%3A00%3A00Z&z=3&v=-2860023.1037379596,-1120673.8055663547,3038216.8962620404,2700894.1944336453

My biggest takeaway is that the open water on the Pacific side is a kill zone for ice that gets transported into it.
Title: Re: The 2018 melting season
Post by: aperson on June 05, 2018, 09:58:42 AM
Euro bottoms out at 972mb. Winds from peak intensity provided below.

(https://i.imgur.com/uT0cBNJ.png)
Title: Re: The 2018 melting season
Post by: uniquorn on June 05, 2018, 10:41:27 AM
Continuing the thawing river series, here are the Shelonsky Islands at the mouth of the River Chondon, east of the Lena delta. Jun2-5

Worldview terra/modis corrected reflectance true color and band 7,2,1
Title: Re: The 2018 melting season
Post by: Pagophilus on June 05, 2018, 04:11:57 PM
Nullschool shows possible unfolding of events in terms of all that fragmented ice in the northern/eastern Kara Sea.   It shows two days (including today) of strong, warm winds blowing ice floes in northern/eastern Kara Sea towards and perhaps into the ice-free Barents.  Followed by two days or more of powerful winds swirling those floes vigorously around.  Waves will get a head start since there is quite a lot of open water in the ice openings parallel to the Russian coast in the extreme eastern portions of the Kara. 

Wind speed readings are for the area just to the right (or south) of Franz Josef Land (green circle dot just visible).  I chose this because it is near the current ice 'edge'.
Title: Re: The 2018 melting season
Post by: A-Team on June 05, 2018, 04:43:18 PM
The MacKenzie started flowing into the Arctic Ocean on about May 30th; the weather at the delta has been cloudy. The 4th of June was clear however. The swath for June 5th is not yet available from WorldView.

Landfast ice is breaking up somewhat and on the move. This date is not unusual for inflow of fresh water here. While it affects salinity and heat of this corner of the Beaufort, it is not currently affecting any area not already melted. While surface ice has been advected west up the Alaskan coast for months by winds, the silt is just spreading out, indicating no current even at continental shelf depths.
Title: Re: The 2018 melting season
Post by: bbr2314 on June 05, 2018, 06:21:08 PM
12z GFS down to 959

(https://www.tropicaltidbits.com/analysis/models/gfs/2018060512/gfs_z500_mslp_nhem_8.png)
Title: Re: The 2018 melting season
Post by: aperson on June 05, 2018, 07:46:22 PM
While surface ice has been advected west up the Alaskan coast for months by winds, the silt is just spreading out, indicating no current even at continental shelf depths.

The silt is also accumulating heat rapidly. Above freezing values are shaded in 0.6C increments starting at -0.3C - 0.3C bucket. The hottest regions are currently around 4C. Models are showing ice getting transported into this region in the D4-D8 range due to actions of the upcoming Arctic cyclone.

(https://i.imgur.com/Vk7zOlL.png)
(June 4th worldview).

Title: Re: The 2018 melting season
Post by: Hyperion on June 05, 2018, 08:40:52 PM
 :'(
And this little children is how we first experienced the awakening of the Atlantic Kraken way back in 2018. Plunging Europe into the tropical monsoon climate we know so well today and rapidly ridding the arctic of this thing we used to call ice. The Kraken began hurling one dripping fisted tentacle a day at the Atlantic north, Europe, and the Arctic ocean back then and almost never paused since in his fury.
One for the ESAS,
Two for the floes,
Three for the Green islands,
Four for Newfoundshoal,
Five from New Fork archipelago,
And so on shall it go?
Title: Re: The 2018 melting season
Post by: Grubbegrabben on June 05, 2018, 08:47:38 PM
12z GFS down to 959

Reposting what bbr2314 said but with this additional quote from the Wikipedia topic "Great Arctic Cyclone of 2012" https://en.wikipedia.org/wiki/Great_Arctic_Cyclone_of_2012 (https://en.wikipedia.org/wiki/Great_Arctic_Cyclone_of_2012).

On August 6, the extratropical cyclone reached a peak intensity of 962 mbar (28.4 inHg), while centered about halfway between Alaska and the North Pole.[1] At this point, the Great Arctic Cyclone of 2012 was the strongest summer Arctic storm on record, since the beginning of records in 1979.

Also screenshot from Nullschool below. This happening in early June as compared to August 6 should have some implications...?

Edit: The location/path of the cyclone does not seem as detrimental as 2012, but I know way to little about this to develop the reasoning further.
Title: Re: The 2018 melting season
Post by: aperson on June 05, 2018, 09:04:33 PM
12Z ECMWF bottoms out fairly early as well with a minimum SLP of around 970hPa. Given the different location and timing of this cyclone compared to the GAC, I think the effects will be qualitatively different and we will need to hold on any comparisons until reanalysis. However, this setup appears to be catastrophic.

(https://i.imgur.com/fHGKIEk.png)
Title: Re: The 2018 melting season
Post by: A-Team on June 05, 2018, 09:58:27 PM
Scientific animator extraordinaire, Kevin Pluck, has some outstanding Arctic and Antarctic graphics on his twitter site ... the one below shows how the weekly ratio of extent to volume has drifted over the years. The loop pinches from 2009 on, explained as a skewed sine curves for the volume and something that produces a sharpish valley for the extent curve'.

The second link below can be used to capture twitter mp4s though that mp4 still has to be converted to forum mp4 using the third link.

https://twitter.com/kevpluck
http://twittervideodownloader.com/
https://www.online-convert.com/
Title: Re: The 2018 melting season
Post by: oren on June 05, 2018, 10:08:23 PM
Great animation.
Title: Re: The 2018 melting season
Post by: A-Team on June 05, 2018, 10:08:38 PM
While not the main weather event at the moment, the weather that swept in from far eastern Siberia over the Chukchi and Beaufort had the effect of disrupting our four favorite radar wavelengths for a couple of days.

There are two Ascat satellites A and B imaging 12 hours apart, making it possible to intercalate them to get slightly smoother image motion. Below, the upper part and elbow of the CAA stringer in the Beaufort-Chukchi are disappearing from view from June 3rd on. The shorter wavelength imagery often has an unwanted weather overlay but Ascat has been largely immune to artifacts for the last ten months.

That's unfortunate since the constituent floes have been trackable since late September. Ascat looks at roughness, more pronounced in MYI; the storm may have had the effect of melting off the rough edges  which makes them less reflective and so darker and not in good contrast with surrounding FYI. Alternatively, the old floes may come back into view as the weather system passes through.
Title: Re: The 2018 melting season
Post by: Ktb on June 05, 2018, 10:46:18 PM
Slater projection shows ice beginning to open in the CAB for July 25th, extremely close to the pole. Extent of 7.42 mil km^2 at that time.

Edit: foolish me, the CAB is already opening thanks to significant torching. I believe the extent graph to be correct but the actual map to be today's date rather than a forecast 40 days out. I will contact UofC once again.
Title: Re: The 2018 melting season
Post by: oren on June 05, 2018, 10:54:39 PM
Thank you A-Team for these numerous Ascat and other animations.
Title: Re: The 2018 melting season
Post by: Pagophilus on June 05, 2018, 11:21:03 PM
Maybe I am missing something, but that Slater projection for July 25 looks a lot more like the current ice extent from AMSR2 for June 5 (today) than it looks like, for example, the actual ice extent for July 25 last year (see below -- I've put all three maps together).  In addition to that, we are at the second lowest measured extent since 1979 for any June 5 right now, implying, at least, that ice extent should look something like last year's extent on July 25.  To me, the Slater forecast looks strange, and I would be glad to be enlightened.

AMSR2 image for July 25 2017 is a little smaller scale than the other maps... apologies.  Pattern of lower extent is still obvious, though.  No ice in Baffin Bay, Hudson Bay, Kara Sea, most of ESS free of ice etc.

Slater projection shows ice beginning to open in the CAB for July 25th, extremely close to the pole. Extent of 7.42 mil km^2 at that time.
Title: Re: The 2018 melting season
Post by: Ktb on June 05, 2018, 11:38:41 PM
Maybe I am missing something, but that Slater projection for July 25 looks a lot more like the current ice extent from AMSR2 for June 5 (today) than it looks like, for example, the actual ice extent for July 25 last year (see below -- I've put all three maps together).  [snip]

I believe you are correct and will attempt to contact UofC once again with our collective concerns. Thank you for paying closer attention than I was!
Title: Re: The 2018 melting season
Post by: uniquorn on June 05, 2018, 11:39:46 PM
I've been looking for a quick way to validate temperatures from models across the Arctic. VIIRS Brightness Temperature (Band I5, Day) and Night overlays seem to work pretty well.
<snippage>

Nice. I edited the palette a bit to show a bigger range of temperatures and stop band15 overlapping the visible ice (just a shame about the clouds)
Temperatures range from ~-1C (light blue) to ~11C(yellow)
It shows Kotzebue Sound warming up very well over the last week.

edit:Not sure that 9C in Kotzebue Sound is that realistic, this might need some more work.
edit2: could be ok, slightly over max average water temperatures for june.
https://www.seatemperature.org/north-america/united-states/kotzebue.htm

Worldview link   https://tinyurl.com/y7parn8f
I only edited Band15, Day and left Night as it was for comparison
Title: Re: The 2018 melting season
Post by: slow wing on June 05, 2018, 11:44:14 PM
Thanks A-Team, I love those Kevin Pluck graphics at #994 (https://forum.arctic-sea-ice.net/index.php/topic,2278.msg157428.html#msg157428)!

That raises an obvious question about a related but simpler plot: has anyone done an extent vs. volume scatter plot for the yearly minima? Presumably! But I don't recall having seen one.

Presuming the plot has been done, would it be amenable to any sort of simple fit constrained to go through the origin & with a finite slope at the origin (corresponding to the average thickness of the remaining ice at the end of the melt season on approaching a blue ocean year)? (A quadratic going through the origin would be the obvious first form to try.) How much scatter would the yearly values have around the fit?

In trying to relate it to the complex physical reality, would it be expected to be predictive at all?

(Sorry for being slightly off-topic, Neven.)
Title: Re: The 2018 melting season
Post by: uniquorn on June 06, 2018, 12:16:50 AM
There are lots of ideas about sea ice minimum prediction here :)
https://forum.arctic-sea-ice.net/index.php/topic,2285.msg156757.html#msg156757
Title: Re: The 2018 melting season
Post by: stjuuv on June 06, 2018, 12:42:37 AM
That raises an obvious question about a related but simpler plot: has anyone done an extent vs. volume scatter plot for the yearly minima? Presumably! But I don't recall having seen one.

Presuming the plot has been done, would it be amenable to any sort of simple fit constrained to go through the origin & with a finite slope at the origin (corresponding to the average thickness of the remaining ice at the end of the melt season on approaching a blue ocean year)? (A quadratic going through the origin would be the obvious first form to try.) How much scatter would the yearly values have around the fit?
Something like this? I didn't match exact dates, but rather used yearly minimum values from these two sources:

Title: Re: The 2018 melting season
Post by: Neven on June 06, 2018, 12:57:42 AM
NSIDC Compactness quite high for the time of year, which suggests there's not much melt ponding going on, and apparently all that water between floes in the Beaufort is too coarse for NSIDC's low resolution (I'll see if I have time tomorrow to look at compactness using other data sources).

But if the forecasts are right, this year's trend line should start to drop more vigorously soon.
Title: Re: The 2018 melting season
Post by: aperson on June 06, 2018, 01:03:22 AM
Updated D1-D9 run of the cyclone from 18z GFS. The D5-D9 window shows an interesting synoptic-scale feature that will likely verify in some form, since there isn't too much variance in the expected speed of the cyclone track. A high amplitude jet streak across North America creates an omega block pattern that the cyclone runs into. This causes the system to stall and slowly track eastward over the CAA, putting the garlic press in full motion for a sustained duration.

https://i.imgur.com/4i3NVed.mp4
Title: Re: The 2018 melting season
Post by: Neven on June 06, 2018, 01:08:09 AM
Very interesting ECMWF forecast, as presented on Tropical Tidbits (https://www.tropicaltidbits.com/analysis/models/?model=ecmwf&region=nhem&pkg=z500_mslp&runtime=2018060512&fh=24). Of course, the strong, but short-lived cyclone, followed by a strange-looking Dipole.  ;)

I'm very curious to see what this will do to the ice, especially in relation to that open water on the Siberian side of the Arctic.
Title: Re: The 2018 melting season
Post by: aperson on June 06, 2018, 01:16:06 AM
Very interesting ECMWF forecast

I'm also excited to see 00z, given that a new release of ECMWF was just deployed:

https://software.ecmwf.int/wiki/display/FCST/Implementation+of+IFS+cycle+45r1

There is one change that should greatly benefit us:

Quote
Weakly coupled sea-ice atmosphere assimilation applied with the use of OCEAN5 sea-ice (instead of OSTIA) in the surface analysis of the high-resolution (HRES 4d-Var) and the ensemble of data assimilations (EDA) analyses;
Title: Re: The 2018 melting season
Post by: jdallen on June 06, 2018, 03:44:00 AM
NSIDC Compactness quite high for the time of year, which suggests there's not much melt ponding going on, and apparently all that water between floes in the Beaufort is too coarse for NSIDC's low resolution (I'll see if I have time tomorrow to look at compactness using other data sources).

But if the forecasts are right, this year's trend line should start to drop more vigorously soon.
I read this, and it just has me scratching my head when I consider (1) the lack of snow cover over most of the pack (2) the serious above normal temperatures we've been having outside of the central pack (3) the relatively cloudless conditions, particularly over the ESS, Chukchi and Beaufort.

I come back to the more recent nature of the pack itself, with much smaller expanses of ice, and less durable as well, and wonder if there is melt ponding, but it is at small enough scales that it's flying "under the radar" so to speak.  The other though I have is, if the ice is sufficiently young, that it may not be sufficiently sealed to permit large standing bodies of water to form and persist.
Title: Re: The 2018 melting season
Post by: Hyperion on June 06, 2018, 04:21:28 AM
Very interesting ECMWF forecast, as presented on Tropical Tidbits (https://www.tropicaltidbits.com/analysis/models/?model=ecmwf&region=nhem&pkg=z500_mslp&runtime=2018060512&fh=24). Of course, the strong, but short-lived cyclone, followed by a strange-looking Dipole.  ;)

I'm very curious to see what this will do to the ice, especially in relation to that open water on the Siberian side of the Arctic.
Strange it may be but that double dipole if it eventuates would be sucking all the heat out of central Eurasia and north America and dumping the Arctic cold down their west coasts, with a new cyclone seeming to be forming up to repeat the cycle.
Title: Re: The 2018 melting season
Post by: Neven on June 06, 2018, 08:57:49 AM
I read this, and it just has me scratching my head when I consider (1) the lack of snow cover over most of the pack (2) the serious above normal temperatures we've been having outside of the central pack (3) the relatively cloudless conditions, particularly over the ESS, Chukchi and Beaufort.

I'm scratching too. What does it take for some serious melt ponding to be produced during May? I hope to find some time this week to compare this May to previous years (particularly 2010 and 2012) and ask Dr David Schröder what his model is saying.
Title: Re: The 2018 melting season
Post by: RikW on June 06, 2018, 09:13:20 AM
My gut feeling says the ice is too poreus to see melt ponds.

Just being fractured won't be enough I'd say. Instead of large melt ponds you have several small melt ponds, but 10 melt ponds of 1 km2 or 1 of 10 km2 is still 10 km2 of melt ponds. If the ice is too fractured I guess we should see it on the satellite images.
Title: Re: The 2018 melting season
Post by: Neven on June 06, 2018, 09:21:28 AM
Over on the extent and area data thread, Wipneus posted this yesterday:

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=2223.0;attach=101853;image)
Title: Re: The 2018 melting season
Post by: Hyperion on June 06, 2018, 09:27:16 AM
Meltponding coming up. Serious drenchings of up to 22 mm per 3hr rain currently underway on the laptev and Greenland coasts. Plenty of inbound TPW to sustain them. Decent falls also up to 5mm per three hours over the ESAS. Temps above freezing surface to high altitude and high winds aloft assure us this is wet stuff. Surface and 850hpa~1.5km shown. In coming ocean heat ramping up via storm surge tsunamis breaching the north sea shallows at depth, and the Newfoundland current pinching of the southern exit route for the Gulfstream by squatting off the coast of Europe.
Title: Re: The 2018 melting season
Post by: Pmt111500 on June 06, 2018, 09:31:33 AM
My gut feeling says the ice is too poreus to see melt ponds.

Just being fractured won't be enough I'd say. Instead of large melt ponds you have several small melt ponds, but 10 melt ponds of 1 km2 or 1 of 10 km2 is still 10 km2 of melt ponds. If the ice is too fractured I guess we should see it on the satellite images.

The extent Vs. Area plays also a part, and various systems of averaging over days. Might be they're still there but drain too fast to get noticed on released numbers.
Title: Re: The 2018 melting season
Post by: aperson on June 06, 2018, 09:45:18 AM
Keeping my eye on some unreal PWATs for the region forecast by ECMWF (and to a lesser extent GFS) after the cyclone crosses over and runs into an omega block.

(https://i.imgur.com/vwXOtDV.gif)
(https://i.imgur.com/ny0ERKb.png)

This would be a substantial rain event across the CAA. A nice cherry on top after the wind, rain, and wave show we're about to witness.
Title: Re: The 2018 melting season
Post by: Often Distant on June 06, 2018, 10:18:58 AM
(https://s33.postimg.cc/ngu37olbz/6_06_10_rivers_surge_lineless.jpg) (https://postimg.cc/image/wbuxi7a4b/)
Title: Re: The 2018 melting season
Post by: Often Distant on June 06, 2018, 10:39:43 AM
Fire.
(https://s33.postimg.cc/h88re2svz/fire_in_alaska_6_6_18.jpg) (https://postimg.cc/image/3rbsv7ikb/)
Title: Re: The 2018 melting season
Post by: Gray-Wolf on June 06, 2018, 11:19:42 AM
Try and carry a plate of water if you roll it from side to side and see how much water is left by the end?

If slight swells pass through shattered ice then how much water will get 'spilled' by the ocean's motion?
Title: Re: The 2018 melting season
Post by: ArcticMelt1 on June 06, 2018, 11:34:58 AM
The past spring is definitely warmer than the spring of 2017.
Title: Re: The 2018 melting season
Post by: Neven on June 06, 2018, 12:09:46 PM
Here are my temperature graphs for May, Atlantic second warmest on record:
Title: Re: The 2018 melting season
Post by: Hyperion on June 06, 2018, 03:34:02 PM
The heat and moisture being dragged in by this beast are already phenominal. Winds and Temp's at 1000hPa
Title: Re: The 2018 melting season
Post by: Hyperion on June 06, 2018, 03:42:28 PM
But it sure is the Green Islands that are copping the rain!
Title: Re: The 2018 melting season
Post by: Hyperion on June 06, 2018, 04:19:41 PM
And holy whirling dervish's Batman, looking 24hrs ahead, we have a swarm of 8 cyclonic circulation's on the water from 30 to 70 degrees nth threatening to suck the entire Ocean of water vapour northwards.
Title: Re: The 2018 melting season
Post by: Pagophilus on June 06, 2018, 05:03:28 PM
The entire Laptev Sea is in line for sustained, strong, warm winds from Siberia for at least four days starting tomorrow, according to nullschool.   In addition, that huge gap in the ice in the Laptev Sea means large waves can develop there.  The Lena River, BTW, has just about melted through the fast ice through to that gap in the Laptev.  Warm waters will be arriving by that route also.

These forecast winds will be coming from the hot central portion of Siberia and they are thus likley to be warmer than those about to blast the Kara.  I will confess I was focused almost entirely on the north/east Kara Sea, because the cyclone is due to pass over there.  But what is happening to the Laptev (and the adjacent CAB) could be significant.  I chose the wind speed and temp point (green circle) in the middle of the Laptev as conservatively reasonable for what might be happening to the sea and ice.
Title: Re: The 2018 melting season
Post by: marcel_g on June 06, 2018, 05:10:56 PM
I'm also very curious as to what will happen to the ice with this cyclone. It looks like the area between Laptev and CAA will get churned up, first with winds pushing the ice towards Svalbard, and then with winds pushing it back.

Laptev looks to get wind and warmth, so how much will it melt back?
how much will that gap open up as the ice gets pushed towards CAA? How much melting will occur under the storm in the CAB? Enough to cause melt ponds? The storm looks to bring cloudy weather, so perhaps maybe not?

On the Pacific side at around 5 days out however, things look bad for the ice. If the forecast holds, that whole side will be getting at least a few da