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Messages - FishOutofWater

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1
Arctic sea ice / Re: The 2019 melting season
« on: August 29, 2019, 12:41:32 PM »
As there is some discussion about ice drift direction, here is osisaf ice drift overlaid onto unihamburg amsr2-uhh, aug18-28.
Arguably amsr2 should be overlaid onto the previous 2 day osisaf but 1 pixel of amsr2, ~15km^2 of slush probably has a fair bit of inertia so in this case day n-2 to dayn osisaf is overlaid onto dayn amsr2-uhh(25-27aug onto 27aug)
Note that although both products use algorithms to interpret the data, both are based on real data and not models.

Quote
Low Resolution Sea Ice Drift product (OSI-405)

Which satellite sensors are processed?
The sensors and channels used are SSMIS (91 GHz H&V pol.) on board DMSP platform F17, ASCAT (C-band backscatter) on board EUMETSAT platform Metop-A, and AMSR-2 on board JAXA platform GCOM-W.

What is the spatial resolution of this product?
The low resolution sea ice drift product is a gridded dataset. The grid has 62.5 km spacing on a Polar Stereographic projection mapping. Definitions for the projection parameters can be found in the NetCDF files as well as in the Product User's Manual.

What is the time-span of this product?
Two days (48 hours). This is the time delay between the start and the stop time of the motion described by one vector. For comparison, the merged products from IFREMER/CERSAT is a 3 days lag dataset while the AMSR-E product by the same data centre is 2 days (using 89 GHz channels).

Several datasets are distributed every day, which one should I use?
The OSI SAF low resolution sea ice drift product is indeed composed of several single-sensor products and one multi-sensor analysis, every day. They are all at the same spatial resolution , on the same grid and with a 48 hours time-span.

The multi-sensor (aka merged, multi-oi) is intended for users requiring a spatial covering dataset. In this product, missing vectors are indeed interpolated from the neighbours and each vector is computed from the individual single-sensor products. In this merging process, however, some level of aliasing and averaging is to be expected that slightly degrade the quality of the dataset.
click to run

2
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: August 17, 2019, 06:46:06 PM »
110 took quite a battering, I'm guessing intersecting waves reflected off the shelves caused a huge pressure spike on the 15th July, it looks like it 'bounced' generating tauroidal 'smoke ring' type wave structures which spread across the whole basin sending shockwaves back which damaged 110 when it approached the shelf/amundsen generated tidal vortices around the 5th. 1.7mb gif won't be here long
link
switched gif for link

3
Arctic sea ice / Re: The 2019 melting season
« on: August 13, 2019, 02:53:53 PM »

It would be interesting to know how much ice the Barnes Ice Cap lost this yet. It seems to have been under blue sky for most of July and August.

I love to see some more data on this do you have any.

Wikipedia says it averages about a meter year lost.

This year probably way abbve that

Here is a timelapse from 1984 - 2018 (Will be interesting to see when they add 2019/2020)

https://earthengine.google.com/timelapse#v=70.08059,-74.06429,6.626,latLng&t=0.03&ps=100&bt=19840101&et=20181231&startDwell=0&endDwell=0

Here you are:

4
Arctic sea ice / Re: The 2019 melting season
« on: August 12, 2019, 10:01:36 AM »
I’m really surprised that the lightning strikes 300 miles from the North Pole yesterday did not cause more discussion on the forum. 

The scientists on climate Twitter could not find any instance of lightning so far north.

It was a strange, and in my opinion important, event.  The arctic is changing!

This is from work, so no one has seen the following pictures... The IFS 0.125° for the 11th at 00Z, wet bulb potential temperature at 850 hPa, vorticity at 850 hPa (above 16, step 4), SLP, thickness 500 (Z500-Z100). There is  a front with a ribbon of vorticity to the North, stretching from the low over Barents to the Chucki sea, with low and mid level clouds, as visible from sat pictures. But associated with the low over Laptev, to the west of the head of the low, there is a maximum of vorticity. Sounding show mid level instability from ~800 hPa to ~250hPa with ~100 to ~200 J/Kg. Marginal, be with good forcings enough for TS.
As Rod said, this is significant.
For one part, this is an illustration of the evolving Arctic. Again, CBs were probably not directly linked to the crazy warm SST, but it is definitively showing that Arctic is warming. The warm air advection was extreme, and was able to carry a potentialy instable airmass up to 85°N. Mid level CBs at the head of a thermal wave are not a thing of the Arctic, up to today...
For the other part, this also means that cyclogenesis is on the move on the Arctic. This low had some characteristics of a warm seclusion with a slight max of temperature, TA and wind around 850 hPa - 900 hPa. Cold, pure baroclinic process are loosing a bit of grip and now warm core process and moist instability is starting to play a role. For the second point, it was of course more evident with the low over Beaufort at the start of the month for example. Here a lone CB will not make any meaningfull difference of course. But next year it could be 10 CBs, then etc... And on the end it will change the cyclogenesis process. It could also be noted that Laptev sea being shallow, it could quickly warm without sea ice. With Siberia snow free earlier and earlier, this could mean a quick increases of moist instability with a warming Arctic.

5
Arctic sea ice / Re: The 2019 melting season
« on: August 12, 2019, 12:22:14 AM »
Probably a Baby Boomer too.
I apologise deeply on behalf of my mother for her carelessness in giving birth to a baby boomer.
I am taking myself to a dark corner to weep and wallow in my misfortune. Woe is me.
"He was despised, rejected of men, a man of sorrows, and acquainted with grief" (Isaiah 53:3)

I guess this is off-topic but.....


6
Arctic sea ice / Re: The 2019 melting season
« on: August 10, 2019, 12:25:44 AM »
You contradict yourself.
Why would you expect the Central Basin to continue behaving as it has when its' neighbors are nearly gone?

Because the "neighbors" basically disappear every year now.

What % of the ice volume at year end is in the CAB? 80-90%?

This year is a great example. The periphery is getting crushed, CAB area is higher than the 2010's average. For the most part, SST's are stalled where the water transitions from shallow to deep.

The $64K question is how do you get sustained heat to the pole w/o warm SST's? You need freak weather as in 2012. That can certainly happen, but we can't predict it. Freak winds can also do the trick, but also not predictable.

The first BOE could come 50 years from now. There's simply no conclusive evidence that we can extrapolate the past losses of the shallow Arctic to future losses in the deep Arctic. Two different animals.
It all sounds nice but not supported by facts:
The Beaufort, ESS, Laptev and Chukchi all trend toward earlier meltout, which does matter to the CAB.
In 2000-2003 CAB volume at minimum was around 8500 km3, while in 2012 it reached 3500 km3, and several years came in at around 4000 km3. With such a change in 10-15 years, what makes you think the rest will take 50 years?
If it takes freak 2012 weather to melt the CAB, how did 2016 match 2012 CAB area? Or even go lower according to NSIDC?
Why do the Laptev Bite and the Beaufort meltout occur early over deep waters, while the shallow ESS normally holds out longer?

7
Arctic sea ice / Re: The 2019 melting season
« on: August 08, 2019, 10:16:22 PM »
Quote
'cold air has been flowing persistently to northern Finland from the Arctic ocean'
and doing its best to take the ice with it. Not that it gets far into atlantic waters.

Today looking at mercator 0m sea temperature with unihamburg amsr2-uhh overlay at 60% transparency this time to allow some of the mercator model's higher coastal SST's beneath the ice to show through. I didn't notice that before doing this overlay. That would explain the rapid melt of ESS/Laptev fast ice. amsr2 0% concentration (open water) has been set to fully transparent, jun1-aug7.
Attention is unsurprisingly mostly on the Chukchi/Beaufort and Laptev at the moment but note also the heat building up to the east of the Fram Strait.
The CAB beginning to resemble a ripe stilton

8
Arctic sea ice / Re: The 2019 melting season
« on: August 06, 2019, 11:30:04 PM »
<>Active strong surface melting continues between the CAA, Greenland and the pole.<>
A closer look at the lincoln sea. Melt combined with warm winds.

9
Arctic sea ice / Re: The 2019 melting season
« on: August 04, 2019, 04:57:12 PM »
Except for an area of the northern Barents sea between Svalbard and FJI which has been cooled by advection of ice into the waters, SSTs are anomalously high on the Atlantic side.<snip>

Yes, SST anomalies have gone crazy recently, on both the atlantic and the pacific side. Animation below for the past 6 weeks.

10
Arctic sea ice / Re: Latest PIOMAS update (August 2019)
« on: August 04, 2019, 02:57:53 PM »
If PIOMAS is calculated by what we see on Wip's first Animation-
then the Reality must be much worse:
no sign of the Break- up above CAA & Greenland, no Rubble in the ESS either.

That sloppy Resolution is just a Joke.
The difference with 2012 shows both of these phenomena clearly. PIOMAS is low resolution but it usually captures these things.

11
Arctic sea ice / Re: Latest PIOMAS update (August 2019)
« on: August 04, 2019, 08:52:00 AM »
PIOMAS gridded thickness data was updated. I calculate volume from the thickness data, gives 6.46 [1000km3] on 2019-07-31. Lowest for the day with a small margin with 2012 (6.68 [1000km3]).

Here is the animation.

12
Arctic sea ice / Re: The 2019 melting season
« on: August 04, 2019, 01:01:55 AM »
Something of a milestone in the high Arctic last month according to ESRL-NOAA.
https://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries.pl?ntype=1&var=SST&level=2000&lat1=90&lat2=80&lon1=0&lon2=360&iseas=0&mon1=0&mon2=0&iarea=1&typeout=1&Submit=Create+Timeseries

For only the fourth time ever the average SST in the area 80N+ was above 0degC.

Air temperatures in the same area were a record high nearly 0.5 degrees above the previous record.

https://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl

13
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: July 25, 2019, 12:10:51 AM »
Frankendoodle,
At 111 km per degree latitude, you're suggesting ice has moved more than 550 km in several days.  Ice in Nares Strait can do that in about a week with the assistance of currents and wind (only at the 'very best' of times), but not anywhere else, unless I'm quite mistaken.

Yes, much ice below 75N (and some above it) will melt out.

14
Arctic sea ice / Re: The 2019 melting season
« on: July 24, 2019, 06:05:53 PM »
Re: the icebreaker.
According to this article the ship had to return due to a leakage in the propellerhouse. The thicknes of the ice was not a problem. The icebreaker was built in Italy and was one year late due to construction problems, according the article. https://www.nrk.no/troms/forskningsskipet-_kronprins-haakon_-skadet-etter-mote-med-is-1.14636312

15
Arctic sea ice / Re: The 2019 melting season
« on: July 24, 2019, 12:07:41 AM »
In areas where sea ice abuts fast ice, the shallow water depth can allow pressure ridges to actually anchor to the sea floor. These structures are called stamukha;

Thank you for your post Ossifrage.   

A few days ago we were discussing images of ice scouring on the sea floor in the area of the ESAS that Natalia Shakhova provided in her 2017 paper, and I was struggling to think of a mechanism that could have caused it.

I completely forgot about stamukha. 

Quote
Stamukha – fixed ice which remained on a shallow of the coast or on a stamik. S. can form on nameless banks, not designated on maps, at the depths over 20 m. The cases are known when S. was formed at a much bigger depth. Around S. ice belt is formed up to 10 miles and more. In summer S. melts and disintegrates, forming mass of crushed and chafed ice, dangerous for vessels, especially in poor visibility conditions. Such hummock ice in shoals of the Arctic Region is a hazard for navigation. The East Siberian Sea has the maximum quantity of S. in the Russian Arctic Region – 71 %, due to harsh weather conditions and shallowness of the sea. In the eastern part of the sea, the largest S. is registered with the maximum draft 35 m. S. often form in the southwest along the borderline of the land ice from the New Siberia Island to the Ayon Island, along the Chukchi coastline, and on banks to the west of the Wrangel Island.

https://link.springer.com/referenceworkentry/10.1007/978-3-319-24237-8_496

16
Arctic sea ice / Re: The 2019 melting season
« on: July 22, 2019, 11:42:33 PM »
I will update the analysis when June 2019 data from MERRA will be available in late July -when nobody will no longer care as sea ice extent will be many thousands squared kilometers below 2012 and the crash will be beyond obvious XD -. Perhaps MERRA datas are going to show a little miracle, against the reanalysis, but is not really likely.

So without any surprise, MERRA2 data backup NCEP/NCAR reanalysis and confirm that the Arctic suck up energy at an impressive pace in June. The first graph updates the scatter plot of September sea ice extent by the NSIDC, versus the June surface net downward solar flux (with a reverse scale on the left, in blue). As forecasted, Arctic (northward of 70°N) surface solar flux reached 120 W/m², a new record. The second and third graph are a quick comparison of accumulated heat in 2019, 2016, and 2012. And last, the map for June 2019, showing the strong signal in Beaufort, Chukchi and Laptev.

This heat will probably have long lasting consequences. It can be noted that the halocline is showing signs of disruption, even in the Beaufort sea :

https://www.whoi.edu/page.do?pid=163197

And in the Chukchi sea, the warmth is even more impressive and is mixing to great depth (up to 100 meters), with major disruption of the halocline probably going on.

In the immediate future, the strong dipole (with a forecasted 50kt jet at 850 hPa ! https://www.tropicaltidbits.com/analysis/models/gfs/2019072212/gfs_mslp_uv850_namer_17.png )  is probably going to help mixing, and hence melting in connection with the warm sea.

P.S. : From a more aesthetic view of the weather, it can be noted that a shallow low is going to "deepen" (around 1000 hPa) over the northern slopes of Alaska due to interaction of the southerly flow with mountains. This low is going to accelerate the flow, with a funneling effect along the coast. Independently from the mentioned jet over Arctic, a strong gale is going to develop over Beaufort and Chukchi sea. Given the situation, mean wind of up to 40 kt at surface seems almost reasonable, but given that the wind is going to blow over open sea this can become quite an event. https://www.tropicaltidbits.com/analysis/models/gfs/2019072212/gfs_mslp_wind_ak_19.png It does not always need a deep low for winds reaching high values.

17
Arctic sea ice / Re: The 2019 melting season
« on: July 22, 2019, 10:46:10 PM »
For the first time in years I checked 500 MB Geopotential height on NCEP-NCAR Daily Composites.

Because I guess I see unfolding what I was prepared to see for some years. This might become the season predicted, a very low extent/area minimum and a long, lingering slow refreeze. then some years of on/off seemingly stabilization. Followed by the feared state change in the Arctic.

The GH anomaly is, in a way, stronger than during may-july '12. Then, it was concentrated over southern Greenland, creating a strong flush-out dipole directed to Fram Strait. Now, the bulge on the mid-troposphere is strong over the Pole.

Coincides with the diagrams FishOutOfWater presented.
Strong influx of heat. Loss of Polar Cell characteristics.

And golfball-like hail in the Netherlands. And a probable all time heat record over here next Thursday.

I don't like to be a pessimist. I'll try to face what's coming with compassion.

Pretty Old Testament, isn't it?

18
Arctic sea ice / Re: The 2019 melting season
« on: July 22, 2019, 01:19:53 PM »
Perhaps more of a worry is that the low concentration area is at the tip of the atlantic current, here shown using mercator salinity at 34m. Note also the lower concentration area above the current further west.
edit: forgot scale

19
Updated volume and volume-anomaly graphs.

20
PIOMAS has updated the gridded thickness data to the 15th of this month. Volume calculated from this was 8.77 [1000km3]. That is the lowest for the day, with quite a margin.

Here is the animation.

Neven, web-master: I can't seem to modify the top post anymore to change the subject of this thread to the latest update.

21
Arctic sea ice / Re: The 2019 melting season
« on: July 21, 2019, 10:42:10 AM »

In spite of what the weather models sometimes report, the actual temperatures in the northern CAA have been very warm over the past several days.   As discussed in previous posts, on July 14, 2019 the weather station at Alert, Nunavut hit 21C the warmest temperature ever measured north of 80 degrees Lat. 

A team of field researchers just wrapped up a 2 week trip on Axel Heiberg and reported widespread permafrost melting.  One of the researchers, professor Gordon Oz Osinski, said “in the 20 yrs since I started fieldwork in the Arctic I’ve never had such a long stretch of sun & temperatures in the teens [C].”  To find the thread, open Twitter and search #AxelHeiberg2019. 

Below is the link to the gif showing the permafrost melting.  It is definitely worth a click.  Pretty incredible sight when you consider that is happening at 79.8 degrees north latitude!

https://t.co/5AFY1BKTVr

I think the crack that has opened (for a few weeks now) north of the CAA will likely be persistent, and could be significant this year.

What you're seeing in the video is likely part of what's called a thaw slump. While the number of them has increased quite dramatically in the Arctic over the last few decades, they are also just a normal occurrence in many paraglacial landscapes and have occurred in the Arctic for millennia.
They happen when layers of thick buried ice get exposed to the air. This can be by erosion from waves, rivers, or from things like heavy rain, which can cause the surface permafrost to detach. When the ice melts back, the soil on top slides down, mixes with the melt water and forms large flowing mud lobes at their front.
Here's 2 examples from my own fieldwork in 2017

22
Developers Corner / Re: Test space
« on: July 19, 2019, 05:40:47 PM »
Agreed. We just get used to scrolling more.
Here testing large mp4 of unihamburg amsr2uhh jun1-jul18 using ffmpeg -crf 29 which compresses to 2.12MB
Quote
Choose a CRF value. The range of the CRF scale is 0–51, where 0 is lossless, 23 is the default, and 51 is worst quality possible. A lower value generally leads to higher quality, and a subjectively sane range is 17–28
not quite sane then.

Obviously it is intended to be viewed full screen - double click probably. Is it too big for mobiles (portables)?

23
Arctic sea ice / Re: The 2019 melting season
« on: July 18, 2019, 07:53:14 PM »
The Coriolis effect tends to make the water flowing into the Arctic, from both the Atlantic and Bering strait, turn right. The warm water in the Bering strait goes into the Alaskan Coastal Current that flows eastwards on the north slope and may also go into eddies on the Chukchi shelf. In the fall the water may sink below fresher surface water forming the "summer water layer". This melting season heat stored from last year may be melting ice that has pushed from the CAA into the Beaufort sea.

You can see the mixing up of the summer water layer heat in recent buoy profiles from the Beaufort sea. That heat is helping to melt the thick multi-year ice imported from the CAA.

The extraordinarily warm water that we see now along the Alaskan coast will not directly affect the ice in the central Arctic but the heat will have indirect effects this year and next year. The continuing build up of heat in the Beaufort sea is leading to "Pacification" of the Alaskan side of the Arctic ocean and is playing a major role in multi-year sea ice decline.

http://psc.apl.washington.edu/HLD/Bstrait/BeringStraitSeasonalInterannualChange2017.html

Abstract 

Year-round in situ Bering Strait mooring data (1990-2015) document a long-term increase (~0.01Sv/yr whole record, ~0.02Sv since 2000) in the annual mean transport of Pacific waters into the Arctic.  Between 2002 and present (2015), all annual mean transports (except 2005 and 2012) are greater than the previously accepted climatology (~0.8Sv).  The record-length maximum (2014: 1.2�0.1Sv) is 70% higher record-length minimum (2001: 0.7�0.1Sv), corresponding to a ~1/4year reduction in the flushing time of the Chukchi Sea (to ~4.5months from ~7.5months).  The transport increase results from stronger northward flows (not fewer southward flow events); the velocity distribution's annual mode ranges from <25cm/s to >40cm/s, a 60% increase in speed and a 150% increase in kinetic energy, a metric which scales with the flow's impacts on bottom suspension, mixing and erosion. 


The Chuckchi sea's sea ice loss and resulting warmth may have profound effects, where the warm sea is warming the Beaufort gyres halocline, potentially slowing sea ice growth. We should worry if the Chukchi is above 13°C

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6114986/


The doubling of BG halocline heat content over the past three decades appears attributable to a warming of the source waters that ventilate the layer, where this warming is due to sea ice losses in the Chukchi Sea that leave the surface ocean more exposed to incoming solar radiation in summer. The effects of an efficient local ice-albedo feedback are thus not confined to the surface ocean/sea ice heat budget but, in addition, lead to increased heat accumulation in the ocean interior that has consequences far beyond the summer season. Strong stratification and weak mechanical mixing in the BG halocline ensure that significant summertime heat remains in the halocline through the winter.

With continued sea ice losses in the Chukchi Sea, additional heat may continue to be archived in the warm halocline. This underscores the far-reaching implications of changes to the dynamical ice-ocean system in the Chukchi Sea region. However, there is a limit to this: Once the source waters for the halocline become warm enough that their buoyancy is affected, ventilation can be shut off. Efficient summertime subduction relies on the lateral surface front in the NCS region between warm, salty water that is denser to the south and cooler, fresher water that is less dense to the north. For longer-duration solar warming (that is, longer-duration ice-free conditions in the region), SSTs on the south side of the front may become warm enough (around 13°C, under the assumption of a 1.5-month ice-free period dominated by solar absorption) that the lateral density gradient is eliminated [see (24)]. It remains to be seen how continued sea ice losses will fundamentally change the water column structure and dynamics of the Arctic halocline. In the coming years, however, excess BG halocline heat will give rise to enhanced upward heat fluxes year-round, creating compound effects on the system by slowing winter sea ice growth.


24
Arctic sea ice / Re: 2019 vs 2012
« on: July 16, 2019, 12:34:45 PM »
DMI's thickness model shows pretty different results to PIOMAS. Where PIOMAS has 2012 and 2019 pretty much tied for volume at this point, 2019 is lagging pretty far behind according to DMI: (click to play)

I asked what the difference between these models are in the PIMOAS thread and why no one seems to talk about DMI, didn't get a response.

DMI uses CICE (and HYCOM for the weather forecast), PIOMAS uses PIOMAS.

DMI is a model to predict extent, PIOMAS is a model to measure total volume. Either can be used for another purpose, but its rather more likely to be bad at it than its primary purpose.

DMI don't publish much on their model so my diagnosis of their weaknesses may miss something important and these weaknesses may not be the critical ones.

CICE is a model developed for GCMs which is portable into weather forecast models rather than climate models, and DMI isn't the only group that has had trouble keeping it numerically stable. (I reckon the stability issue probably arises from calculated salinity being extremely sensitive to measurement error in assimilated temperature.)  DMI publish on their model rather less than they tweak it, so its not possible to be sure just what they are doing at the moment, but last time I found something on it they were assimilating a large chunk of climatology as well as data.

DMI has an issue with melting momentum. They hit volume minimum too early and have a much too steep melting curve during the summer. I think this probably derives from their sea model being a weather forecast model rather than an ice melt model and heat that should be going into a near surface sea layer in June/July and getting back to the melt ice in August/September, is being put directly into melting ice.

If you use the same DMI model to compare 2012 and 2019, its probably not too misleading, but you need to be sure its a reanalysis of 2012 using the 2019 model, because otherwise you'll be looking at the difference between their 2012 model and their 2019 model rather than the ice. (and if its a big difference, you'll can't tell whether its real or whether the model is having one of the years in which it goes haywire)

25
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: July 11, 2019, 03:22:28 PM »
A cautionary tale

There is great excitement over the area losses in the ESS, which are very large indeed.

So I had a look to see if ESS area was lowest in the satellite record. It is not.
So I had a look to see in which year on this day was area lowest.

The answer?1990, 29 years ago.

So I added 1990 to the graph (see below). If you were a looking at it in 1990 at this , time you might say - "Well that's the end of Arctic Sea Ice".

But it took at least another 15 years for an average minimum to catch up with 1990, and as at 10th July 2019 1990 remains the lowest area for that date and for many days before and for a few days after.

26
Arctic sea ice / Re: The 2019 melting season
« on: July 11, 2019, 01:48:25 PM »
worldview terra modis overlayed with unihamburg amsr2-uhh at 35% transparency, may1-jul10. amsr2 100% concentration has been set to transparent to allow worldview features to show through. There is some misalignment in floe movement, probably due to images formed at different hours during the day. This method helps to continue to see ice movement 'through the clouds'
Large format to show detail, best viewed full screen. (double click)
Both sets of images have small contrast adjustment.
edit: Much of the 'blueing' is from the amsr2 layer, indicating lower concentration ice, slightly darker due to the contrast adjustment
added amsr2-uhh, jul10 for clarification

27
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: July 10, 2019, 04:26:31 PM »
NSIDC daily extent
Almost 800k in four days. If tomorrow goes similar, we might have a double century in the 5-day average, or 1 mill loss in 5 days!
Attached two-frame comparison of 1-week Jul 9 vs Jul 2 UH AMSR2, see the continuing Chukchi/ESS drop

28
Arctic sea ice / Re: The 2019 melting season
« on: July 09, 2019, 02:03:43 AM »
Dr. Judah Cohen has updated his Arctic Oscillation and Polar Vortex Analysis and Forecasts. 

It is a little too technical for my understanding, but some of our weather experts might enjoy taking a look at it.  The link is below:

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


29
Arctic sea ice / Re: Latest PIOMAS update (July 2019)
« on: July 08, 2019, 04:44:13 PM »
CAB volume loss from maximum of each year expressed as a percentage. 100% is at different dates.
2012-2019 edit: added 2011 for a different perspective. (2011 max was day104)
editt: Should have CAB in the title

30
Arctic sea ice / Re: Latest PIOMAS update (July 2019)
« on: July 08, 2019, 08:54:24 AM »
Wow, look at average thickness drop. I'll have a PIOMAS update on the ASIB later today.

PS Volume drop for second half of June was 3989 km3, so I wasn't too far off with my 'around 3850 km3'.

31
Arctic sea ice / Re: The 2019 melting season
« on: July 03, 2019, 03:35:38 PM »
Thanks, I’ll try to get one per week, added to the calendar.
Yes, this is a helpful way to visualize changes. Look at that Beaufort and west CAA region.

Models may be calming down some, but forecasted SLP anomaly and 14 day -AO doesn't look promising.

32
Arctic sea ice / Re: The 2019 melting season
« on: July 02, 2019, 03:05:32 PM »
Sea ice concentration, June 17 – July 1

Huge export of ice coming down into the Fram (I wonder how much of that is MYI).

ESS, Laptev, and Beaufort are lighting up.

CAA is continuing to dwindle away.

33
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: June 29, 2019, 01:04:37 AM »
Uniquorn, I was looking at itp110 data for their SAMI which measures pCO2 and it appears several things have happened over the last couple weeks as the itp bouy switched direction . There was some warm pacific summer water that is the red colors on the temp/salinity contours,  the pCO2 increased as would be expected with an inflow of pacific water, the salinity jumped at the depth of the SAMI and there is a huge shift in PAR. Photo Active Radiation
https://www.researchgate.net/post/Can_I_convert_PAR_photo_active_radiation_value_of_micro_mole_M2_S_to_Solar_radiation_in_Watt_m22

So even though the bouy hasn't hit open water a very large jump in solar radiation has already occurred.
https://www.whoi.edu/page.do?pid=163197
Here is the SAMI info for itp 110


34
Arctic sea ice / Re: The 2019 melting season
« on: June 25, 2019, 12:02:51 PM »
2019 is certainly still in the running for a top 2 finish (+/- 1), with the two main reasons besides the relentless weather:
Low area inside the Inner Basin (courtesy of Wipneus).
Extreme export into the Atlantic throughout the season, which has taken a lot of the MYI - shown in lighter shades on Ascat - out of the basin (courtesy of A-Team in the Test Space thread). The FYI has now reached the North Pole.

35
Arctic sea ice / Re: The 2019 melting season
« on: June 22, 2019, 08:56:03 PM »
Lena Delta, 02.06. to 22.06 via Sentinel.

(click to play)

36
Arctic sea ice / Re: The 2019 melting season
« on: June 22, 2019, 08:10:48 PM »
ascat with unihamburg amsr2uhh overlaid at 70% transparency and 100% ice (white) set to transparent, jun1-21.
Quite a mobile pack with a swift, probably temporary, change of direction in ice heading for fram export over the last two days. The caa-cab crack has snapped shut, maybe also temporarily.
used gimp optimisation to reduce size from 6.2 to 3.8MB. Gimp deoptimise can be used to restore individual frames

37
Arctic sea ice / Re: The 2019 melting season
« on: June 19, 2019, 08:46:39 PM »
This is from Ostrov, Russia. 

A little port on some Islands between the Laptev and ESS.

From 12z today.

So 20 KT sustained SSW winds with 12-13C surface winds and 9C dewpoints.

That's insane.

No coastal fronts holding that back.

Expect incredible melt ponding behind this warm front tracking the Pacific side.

I attached a Google map of where this sounding is from.

38
The volume and volume-anomaly graphs show how close 2019 is tracking 2012.

39
PIOMAS gridded thickness data was upgraded to 15th of June. Volume calculated from thickness is 16.02 [1000 km3]. This is third lowest place behind 2017 and 2012, but the difference with 2012 is really within the error bars that my volume calculation has.

Anyway here is the June animation.

40
Permafrost / Re: Toward Improved Discussions of Methane & Climate
« on: June 18, 2019, 06:48:54 PM »
Quote
Palatability is another question. It appears cows do not like the taste of seaweed—when Asparagopsis was included at 0.75 percent of the diet, researchers observed a drop in the feed intake by the animals.
When doing field geology on the coast of New Zealand, there were 'always' cows eating seaweed at low tide, walking among the slippery boulders to get to their food-of-choice. (stock picture attached)

For decades there were cows who at lakeweed in the St. Marks River - again, this was these cows preferred diet.  (The cows were evicted due to cow rear-end 'water pollution'.)

(reference)

41
Arctic sea ice / Re: The 2019 melting season
« on: June 17, 2019, 04:50:37 PM »
Sea Ice Concentration, June 2 – June 16

42
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 15, 2019, 09:04:29 AM »
Despite the headline extent numbers being what they are, anyone who becomes complacent at this stage is not looking at the whole picture. Look at the ice that is supposed to survive the melting season, the one in the inner basin. Look at its current area.

43
Arctic sea ice / Re: The 2019 melting season
« on: June 15, 2019, 12:49:33 AM »
unihamburg amsr2uhh overlaid onto ascat with 100% ice (normally white) set to transparent. The amsr2 overlay is 70% transparent to allow other features of ascat to show through, notably greenland. It also helps to make the 'weather' over open water less distracting.
Similar to last year the wash of warm weather has revealed fractures in the older ice that were not visible previously.
jun1-13
thanks to A-Team for helpful hints, some of which need further work
https://forum.arctic-sea-ice.net/index.php/topic,2558.msg205561.html#msg205561


44
Arctic sea ice / Re: The 2019 melting season
« on: June 14, 2019, 07:50:12 PM »
I would guess that was the landfast ice on the coast of NW Greenland.

Good guess!

46
It's going to look something like this:



This animation is from one the first blog posts on the ASIB, almost 9 years ago to the day.

47
Arctic sea ice / Re: The 2019 melting season
« on: June 08, 2019, 04:38:40 PM »
This page provides quite a lot of good information about snow melt processes, including sublimation:

http://portal.chmi.cz/files/portal/docs/poboc/CB/snowmelt/print.htm

With respect to the process I was describing, it has this to say (my bold):

When vapor pressure decreases with height in the atmosphere, moisture from the snow will be diffused to the atmosphere above. In this situation, moisture sublimates from the snow, latent heat is lost from the snow, and the snow stays cold, even if the air temperatures are rather warm.

When vapor pressure increases with height in the atmosphere, moisture from the atmosphere above will be deposited to the snow's surface. In this situation, latent heat is gained by the snow, and the snow surface will warm. This warming may start the melting process within the snowpack. To achieve melting in this manner requires winds strong enough to induce turbulent transfer, so that warmth and higher humidity from above continually come into contact with the snow surface.

48
Arctic sea ice / Re: Albedo-Warming Potential
« on: June 08, 2019, 01:07:52 AM »
The recent warm temperatures over the central Arctic did not result in a significant albedo drop. I suspect the peak sunshine intensity this far north is just too low to force widespread meltponding. Without imported heat from the south it just stays an iceblock. It's like trying to melt some metal in a common household oven. You can heat it for a few days, but you never melt the surface unlike a few minutes in a furnace.

The absence of importet heat means 2016 won the battle for first place and in a few days begins the dominance of 2012 until the end of the melting season.

49
Arctic sea ice / Re: The 2019 melting season
« on: May 17, 2019, 12:41:21 PM »
The whole Arctic pack is rotating clockwise now. The ice has transform faults all around the CAA and Greenland. Faults are continuous in ice on the north of Ellesmere island on today's Aqua image.
A bit of a 'hill start' but ice north of caa definitely joining the rotation now.
Worldview terra modis may10-16. https://go.nasa.gov/2EinfAu

50
Arctic sea ice / Re: The 2019 melting season
« on: May 13, 2019, 03:16:26 AM »
I haven't followed any of this so bear with me if this is a wrong conclusion.

But it looks like the Euro and the global forecasting system.  I'm using talk to text that's why I didn't just say GFS because sometimes it doesn't come out right.


Anyways both of them at least on their runs today in about 48 to 60 hours start essentially a hemispheric wide pattern change and the upper latitudes.

You can see not just high pressure blowing up in around the Beaufort sea.

But the huge banana high pressure structure becomes evident.  With the cut-off vortex just south of Greenland and over Eastern Canada.

The way the euro depicts this straight nasty.

But both models are now onto this.


Infact the GEM and UKMET is going down the same path.


For those who are not aware:


Meteorology speaking this setup is essentially the Holy Grail of having a record-setting Arctic sea ice loss during the summer.

Solar energy right now is booming over the arctic.  The best way to set up things for huge loses of sea ice is sprawling upper level atmospheric ridges of high pressure that exist from top down.

This is the path to dry sinking air and wall to wall sunny skies. 

We have never had a May 20-30th GARGANTUAN RIDGE that preconditioned the ice for huge June and July loses.


Stay tuned

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