Author Topic: Short to Medium Term Arctic Sea Ice Conditions Discussion  (Read 135203 times)

Jim Hunt

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1000 on: August 01, 2013, 08:34:18 PM »
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Bob Wallace

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1001 on: August 01, 2013, 11:06:18 PM »
What are the chances we end up with no new record in terms of surface area but that the volume minimum is worse this year than last?

I've actually not seen any recent figures for current volume vs the previous year

I would suggest looking at Wipnues' regional charts for extent and area.

https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-extent-regional.png

https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-area-regional.png

Look at the regions that reached ~zero in 2012 and compare 2013 melt do date.  Look at the ones that didn't melt out but stabilized before the end of the season.

The only region that might not melt out this year but did last is the Beaufort.  And that looks 50:50 with apparently some strong heat coming on.  If I lay a straight edge on the 2013 melt line it reaches zero by the end of the season.

The Greenland is lower than last year and fast ice is breaking away to be melted.  I'd guess some advantage to 2013 there.  (That fast ice shedding is fascinating.)

The big boy, the Arctic Basin, is where the race is being run.  And right now the ponies are neck and neck.  The racetrack touts are telling us that the CAB ice is in worse shape this year.  That there is less MYI.

At this point in time I'd say it's a race far too early to call.  It's going to probably depend on August weather.   (Just think what could happen if August presents us with a big storm like in 2012.)

Back to your first question.  If the CAB stalls out then probably no new volume record.  If 2013 comes at least close to 2012 then a new volume record is likely.


Jmo

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1002 on: August 02, 2013, 07:19:50 AM »
Not implying anything (given that many predictions/assumptions previously made this year have gone nowhere fast...), but ECMWF forecasts again look interesting, with the standout being warm air moving over Beaufort and CAA for the forecast 1-9 days out.
Also, if the big forecast low in the Bering Sea actually eventuates, what impact, if any, could it have on sea ice in the Arctic?  I am aware that is a completely naive question;D , but it seems a strong forecast storm event (that is likely to change?).   Probably more relevant (and coupled with the warm air over CAA) for potential impacts on the ice is the low system simultaneously forecast for the Laptev /CAB area...
« Last Edit: August 02, 2013, 07:26:30 AM by Jmo »

werther

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1003 on: August 02, 2013, 09:16:26 AM »
Remembering my post from eight days ago on the blog, I’m now starting to get the sense of a real cliffhanger. Seven days with more or less a stall in the numbers…

Like Jmo posts above, ECMWF does show some action:


SLP 985Hpa for next Friday? Could do something…

But the stubborn Kara Sea “fast ice” is still there, even the remnants in the Laptev Sea near Cape Bhuor Kaya just won’t pass…

But when the final roar over this season breaks, don’t forget the details!
This is one some 150 km from the Pole, CAB tile r04c03:


Enhanced, to make it speak, but, if you prefer the original:


It took me some clicking through MODIS history to find the corresponding part for last year (lots of clouds over there 28/7 to 1/8 '12).

What I get out of this is that structure in a large part of what was “solid mesh-pack ice” last year at minimum now has broken up into patternless floes.
We could discuss endlessly whether April-June was not conducive to get new record numbers. But the trend to much more mobility in the pack hasn’t stopped.

I wonder what PIOMAS will show when you consider this CAB structure change. This must have physical consequences, on quality and also on thickness…

Laurent

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1004 on: August 02, 2013, 10:09:39 AM »
I have eaten a good icecream made by mixing icycle and salt, really cool (-21.1 °C)

http://sci-toys.com/scitoys/scitoys/thermo/ice_cream/ice_cream.html

All over the Arctic there is icycle mixing with salt ! Without milk beuuuhhh !!!

helorime

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1005 on: August 03, 2013, 01:43:03 AM »
Looks like there is a little hole in the ice showing up pretty much right at the pole http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?mosaic=Arctic.2013214.terra.1km
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Pmt111500

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1006 on: August 03, 2013, 04:40:11 AM »
"Seven days with more or less a stall in the numbers…"

I measured some 20 floes yesterday from the tiles on CAB. It looks like the floes in ice cap are pretty uniform all the way through from NA to European side but with some  more larger floes north of Svalbard. I haven't got the time this weekend to do this for some earlier date to get a measure of the reduction in average floe size. There were large areas of ~4 km diameter floes irregularly dotted with larger ones, surrounded by smaller floes, seen almost anywhere clouds were away. Is the seven day stall the final breakup to smallest measurable floes or what? There's been some precedents of stalls this long, Aug4-Aug12th, 1979 ; 1-17th Aug, 1985 ; Jul31-Aug6th, 1997 ; and one even as early as Jul22-29, 2001 ; what ever else this means, it's about a 'once in seven years' event (5times/34 years).
« Last Edit: August 03, 2013, 05:04:10 AM by Pmt111500 »
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frivolousz21

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1007 on: August 03, 2013, 08:40:09 AM »
The 00z GFS is quite a bit worse.  It crushes parts of the CAB, The Beaufort, and the CAA.

Outside of that it has a more organized dipole than before.  It really dominates late.

Wild times.

SLP at the end is far to close to the Atlantic side.  The Laptev compaction would be huge if that blows up and sits there at 985 for any length of time.



werther

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1008 on: August 03, 2013, 08:48:13 AM »

The latest ECMWF model forecast for next Friday still holds on to a new Low. Going under 980Hpa and right over the “splinter-zone”. Waiting for the Saturday run…

werther

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1009 on: August 03, 2013, 09:02:37 AM »
Quote
Looks like there is a little hole in the ice showing up pretty much right at the pole

You’re right, I think, today MODIS shows the "splinter-zone" has completely covered the Pole. Haven't CAD-ded it yet, but several hundreds of meter wide leads are now within kilometer-range.

In a sense, we're at "ice-free North Pole" now. Time to consider whether the structured mesh-pack now has finally collapsed and we're looking at an Ocean of Debris.
Have to wait for good cloudless images to figure this out.

frivolousz21

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1010 on: August 03, 2013, 09:09:46 AM »
The Euro goes Beast Mode.

WOW. 


What a huge trend to some torching and a dipole.




CraigsIsland

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1011 on: August 03, 2013, 10:57:16 AM »
Wow indeed. This season is not over by any probability.

Ugh.

Jim Hunt

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1012 on: August 03, 2013, 11:27:33 AM »
In case the clouds cover it up later, a first glimpse of the North Pole Hole:

[Edit - Updated the image. In the end Aqua did rather better than Terra]
« Last Edit: August 03, 2013, 09:00:27 PM by Jim Hunt »
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Shared Humanity

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1013 on: August 03, 2013, 03:56:19 PM »
In case the clouds cover it up later, a first glimpse of the North Pole Hole:

[Edit - Updated the image]


If the bulk of the CAB retains this fractured, slushy state going into the freeze, what will be the effect on the strength of the CAB after the freeze? Could the presence of this ice and the low SLT result in a dramatic freeze and growth of volume?

Nightvid Cole

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1014 on: August 03, 2013, 04:44:51 PM »
In case the clouds cover it up later, a first glimpse of the North Pole Hole:

[Edit - Updated the image]




If the bulk of the CAB retains this fractured, slushy state going into the freeze, what will be the effect on the strength of the CAB after the freeze? Could the presence of this ice and the low SLT result in a dramatic freeze and growth of volume?


Yes, but it will probably be delayed quite a bit by the high upper ocean heat content in that area (which I am presuming so since the ice has been broken up since mid-June and thus allowing a lot of solar radiation to penetrate into the sea).

I do expect to see the PIOMAS volume be below last year in October.

ktonine

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1015 on: August 03, 2013, 05:30:40 PM »
If the bulk of the CAB retains this fractured, slushy state going into the freeze, what will be the effect on the strength of the CAB after the freeze? Could the presence of this ice and the low SLT result in a dramatic freeze and growth of volume?

Not sure how this would make any sense logically.  The presence of open water where typically there was ice will retard ice growth.  So the energy that would have went into making existing ice thicker, instead goes into making new ice.

Remember that once average temperatures are below -2C the ocean will be a heat pump warming the air anywhere there is open water.  This will make air temperatures look anomalously high compared to years where there is a more intact 'lid' to the ocean.  This is also true of thin ice compared to thick ice.

Melt ponds can begin refreezing once the temperatures drop below 0C - the ocean requires those temperatures be lower.  Once temperatures drop low enough there will be a 'dramatic' refreeze - but this will be areas that were *previously* ice covered. These areas will be playing catch up, not increasing volume over previous years.

Because thin ice grows quicker than thick ice it may be true that more ice will grow in an open water area than in an ice-covered area - but this is only true because there is so much more capacity to fill.  In other words we might see a statistic that says 'more ice grew north of 80 degrees than ever before" and at the same time see the lowest volume ever for ice north of 80 degrees.  The two statements are not inherently contradictory - we see this for the arctic as whole - as minimum extent decreases winter regrowth increases - just not enough regrowth to make up all the summertime losses.

Vergent

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1016 on: August 03, 2013, 06:25:23 PM »
One thing that ignored in the open water vs ice covered "negative feedback" argument is the melt pond volume. Melt ponds are counted as ice, and the ice cannot thicken until they are frozen. So on paper there is no volume gain until that happens. The reality is that the melt ponds freeze long before open water starts to freeze. There can be 20-30 cm of real ice formation that is a head start for the ice covered area. It just is not counted because we cannot measure it.

Vergent
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Sigmetnow

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1017 on: August 03, 2013, 07:42:40 PM »
August 2, 2013
Northern lands continue to burn:

The Siberian city of Norilsk has been above 83°F (28.3°C) for eight consecutive days starting July 18.  Wildfires are burning a more central portion of the taiga than normal; heavy smoke from them grounded commercial flights in Omsk, a city in southwestern Siberia, and is also drifting toward the Arctic.  The average July high temp in Norilsk is 61°F (16°C).

Alaska is also suffering from heat and wildfires. “Fairbanks is nearing its all-time record for the greatest number of 80-degree days, having had 29, which is well above their average of 11 such days in a typical summer.”

http://www.climatecentral.org/blogs/sunburn-in-siberia-heat-wave-leads-to-wildfires-16313

ChrisReynolds

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1018 on: August 03, 2013, 08:09:57 PM »
August summary of the atmosphere and the failure of the Arctic Dipole in my latest blog post.
http://dosbat.blogspot.co.uk/2013/08/july-status-part-2-atmosphere.html

Ktonine/Shared Humanity,

I expect ice volume growth this year to be very vigorous. Actually for areas where there's already ice the growth is less than for open water or low concentration ice because the existing ice acts as an insulator. Most of the rapid thickening happens when the ice is under 1m thick, over that and the thickening process is slower. But Ktonine is correct, just because we may see ice area of the sort seen before 2007 at the minimum, this does not mean we'll see volume up to those levels. A lot of MYI volume has been lost since then and FYI only grows up to 2m thick, even when growing on existing ice it doesn't get much thicker.

Richard Rathbone

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1019 on: August 03, 2013, 10:18:45 PM »
Chris

Have you got any comparative numbers for the how the differences in heat transport from the different air motion at different temperature, compare to the differences in insolation from different cloud patterns? I'd have thought it was the differences in clouds rather than the differences in winds between the patterns that was likely to be dominant.

I can make an estimate for the direct difference the winds make from the figures in your blog, but I haven't got anything to go on for clouds.

ChrisReynolds

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1020 on: August 03, 2013, 11:26:23 PM »
Richard,

COADS clouds is available,
http://www.esrl.noaa.gov/psd/cgi-bin/data/composites/printpage.pl
But the far north is a blank space, there's OLR from that data, but nothing that helps with insolation.

It may be difference in clouds and incident insolation, but the literature refers to warm air transport and Pacific water through Bering with regards the AD.
« Last Edit: August 03, 2013, 11:48:19 PM by ChrisReynolds »

Richard Rathbone

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1021 on: August 04, 2013, 03:50:59 AM »
I had a play with the ESRL data. Nothing interesting I can see on clouds. However, I think you are reading low temperatures over Greenland as low temperatures over the ocean.

Take a look at the spatial variation of the temperature for 2013 compared to 2007-2012 average. Colder Greenland and CAA is always the biggest effect, but while a lot of the ocean is colder in the May and June comparisons, in July its neutral or warmer.

I still think substantial PIOMAS catchup in July is on, likely record melt for July, but not enough to catch up on the degree its fallen behind earlier in the year. Those numbers should be out soon enough though.

Vergent

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1022 on: August 04, 2013, 04:49:04 AM »
PIOMAS updated

212   7.104

Tied with 2010 1.2k more than 2012. I think PIOMAS is drifting from reality, the ratio of thick to thin has made it optimistic. CRYOSAT2 saw a 8% decrease in average thickness, PIOMAS did not. When are they going to come out with the winter thickness map?

Vergent
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ChrisReynolds

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1023 on: August 04, 2013, 07:56:08 AM »
I had a play with the ESRL data. Nothing interesting I can see on clouds. However, I think you are reading low temperatures over Greenland as low temperatures over the ocean.

Take a look at the spatial variation of the temperature for 2013 compared to 2007-2012 average. Colder Greenland and CAA is always the biggest effect, but while a lot of the ocean is colder in the May and June comparisons, in July its neutral or warmer.

I still think substantial PIOMAS catchup in July is on, likely record melt for July, but not enough to catch up on the degree its fallen behind earlier in the year. Those numbers should be out soon enough though.


I am quite clear that temperatures I use are for the regions I state, yes parts of Greenland and the CAA are included, but most of the regions are the ice pack. Furthermore the lack of AD influx from lower latitudes is clear - this implies less warm influx. In summer temperatures at the surface over the ice are pinned to zero (give or take), but you can see from the cross sections that this is close to the surface.

EDIT



Temperatures from east of Tamyr Peninsular, to Banks Island, north of 70degN.

EDIT again...

Temperatures over Greenland north of 70degN, link, that's direct to the system, give it time to work. Greenland shows similar behaviour to the above graph. But it is a 2degC drop as opposed to the 1degC drop over the rest of the pack.
« Last Edit: August 04, 2013, 08:36:02 AM by ChrisReynolds »

ChrisReynolds

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1024 on: August 04, 2013, 08:31:02 AM »
PIOMAS updated

212   7.104

Tied with 2010 1.2k more than 2012. I think PIOMAS is drifting from reality, the ratio of thick to thin has made it optimistic. CRYOSAT2 saw a 8% decrease in average thickness, PIOMAS did not. When are they going to come out with the winter thickness map?

Vergent

I really don't think it is wrong. July losses were average, but spring losses far less than 2010 to 2012 spring losses, this fits with the cold May and lack of development of AD in June. It is the lack of spring loss that has put this year behind, and thus implies the power of the spring loss in 2010 to 2012. To clarify, this year did have a spring loss, but it was far more muted than the three preceding years.

frivolousz21

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1025 on: August 04, 2013, 10:42:28 AM »
The models are now going to a major dipole anomaly with a major cyclone.


That is INSANE. 




Neven

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1026 on: August 04, 2013, 11:09:03 AM »
What, another cyclone that goes below 980 hPa? If this comes about, 'insane' will be the word.

Last year was the year of the cyclone. This year could be the year of the cycloneS.
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BornFromTheVoid

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1027 on: August 04, 2013, 12:58:46 PM »
Current outlook as shown by the ECM, and to a lesser extent, the GFS, would have us easily beating the early August losses from 2012.

The general pattern starts off benign enough, but quickly turns by 3 days out, as the ridging over the Beaufort area strengthens the high pressure there, while errant jet stream fragments combine to cause a rapid intensification of the low over the ESS/Laptev sector.

t48: Nothing much going on, weak surface high to the west, slight low pressure development to the east, shown by the white oval.



Rapid intensification occurs over the next 24 hours, with the low deep enough and the pressure gradient steep enough to cause some damage. Main wind direction in wine.


By t96, the low pressure has grown to cover about a third of the Arctic, with a central low pressure below 980hPa and a very wide wind field, strengthened by the high pressure to the west of the Arctic.


We can see a strong, almost jet streak feature cross the N. Pole at t96. This feature is a strong contributor to the rapid low development, and continues fueling the storm up to t120.
t96

t120: The Arctic jet streak has the highest jet stream speed in the entire northern hemisphere!


Below shows the areas likely to be affected by the storm from t48 to t96 (white, white, black)


Looking at the details further than t96 is a bit dodgy at this stage, given how unusual this set up is. It does appear, with agreement from the ECM and GFS, that the low pressure will gradually weaken and hang around just north of Svalbard between t120 and t168 (5-7 days out), while high pressure builds over the Pacific sector of the Arctic, introducing milder air to the region.

From 8-10 days out, the 500hPa GPH chart suggests little change, with a stronger dipole like set up than we've seen all summer.


With all this in mind, some very high melt rates could be on the cards starting from the middle of next week. A mixture of storm damage, upwelling, export, compaction and general melting could well produce a second period with 7 day losses exceeding 1 million km2.
« Last Edit: August 04, 2013, 01:10:57 PM by BornFromTheVoid »

anonymous

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1028 on: August 04, 2013, 02:56:17 PM »
Thanks, BFTV!

Combine this forecast with recent Healy images and prepare for basin filled w/ ice soup.

Richard Rathbone

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1029 on: August 04, 2013, 05:25:25 PM »
Chris,

The link in your last post is broken, it just gives me a page not found error message.

Take the same temperature comparison as in Figure 11 of your blog, but for surface temperatures on a polar projection. Look at that plot and I think its clear the Greenland tail is wagging the arctic dog when you do the averaging over the whole area.

I am not sure if it will directly link, but this is the plot I am talking about.

http://www.esrl.noaa.gov/psd/cgi-bin/data/composites/comp.pl?var=Air+Temperature&level=Surface&mon1=6&mon2=6&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&ipos%5B1%5D=2013&ipos%5B2%5D=2013&ineg%5B1%5D=2007&ineg%5B2%5D=2012&timefile0=&tstype=0&timefile1=&value=&typeval=1&compval=1&lag=0&labelc=Color&labels=Shaded&type=1&scale=100&labelcon=1&switch=0&cint=&lowr=&highr=&proj=Custom&xlat1=70&xlat2=90&xlon1=0&xlon2=360&custproj=Northern+Hemisphere+Polar+Stereographic&level1=1000mb&level2=10mb&Submit=Create+Plot

BornFromTheVoid

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1030 on: August 04, 2013, 06:05:43 PM »
The storm is still there on the GFS reaching peak strength at about t84 - t90, not quite as strong of the ECM, but quite impressive all the same. It begins developing a little earlier on this run, with winds strong enough to really affect the ice within 2 days

t48


t90

ChrisReynolds

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1031 on: August 04, 2013, 07:16:11 PM »
Chris,

The link in your last post is broken, it just gives me a page not found error message.

Take the same temperature comparison as in Figure 11 of your blog, but for surface temperatures on a polar projection. Look at that plot and I think its clear the Greenland tail is wagging the arctic dog when you do the averaging over the whole area.

I am not sure if it will directly link, but this is the plot I am talking about.

http://www.esrl.noaa.gov/psd/cgi-bin/data/composites/comp.pl?var=Air+Temperature&level=Surface&mon1=6&mon2=6&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&iy=&ipos%5B1%5D=2013&ipos%5B2%5D=2013&ineg%5B1%5D=2007&ineg%5B2%5D=2012&timefile0=&tstype=0&timefile1=&value=&typeval=1&compval=1&lag=0&labelc=Color&labels=Shaded&type=1&scale=100&labelcon=1&switch=0&cint=&lowr=&highr=&proj=Custom&xlat1=70&xlat2=90&xlon1=0&xlon2=360&custproj=Northern+Hemisphere+Polar+Stereographic&level1=1000mb&level2=10mb&Submit=Create+Plot


Try...

http://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries.pl?ntype=1&var=Air+Temperature&level=2000&lat1=70&lat2=83&lon1=300&lon2=330&iseas=1&mon1=5&mon2=6&iarea=1&typeout=2&Submit=Create+Timeseries"

You are now answering a different question!

Use this page:
http://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl

Use the graph I produced for the arc from Tamyr to Banks north of 70degN, make sure you select 'area weight grids' or the result will not be physically realistic. You can see the graph I produced, you can even select an area of N Greenland without ocean. Then you can select numeric output (Raw Data Values).

Here are the temperature averages post 2007 years for the region of ocean defined above.

2007   4.432
2008   3.703
2009   3.401
2010   4.476
2011   4.445
2012   4.95
2013   4.147

The average of 2007 to 2012 is 4.2345degC, you can see that this is above 2013, the difference being 0.0875degC. i.e. no significant cooling, certainly not as great as I show in those graphs.

But I did not answer the question relating to the 2007 to 2012 average that you posed.

What I said in my blog post was:
Quote
This lack of warm air influx has affected temperatures at the surface in both July and the June/July average, here for the region north of 70degN. There has been a warming in recent years, and so far 2013 represents a downward excursion from that trend.


I followed up by looking at Jun/July average and said:
Quote
For the June/July average the cooling is seen to be more striking.


Nowhere have I claimed that the average temperature of 2007 to 2012 exceeds the temperature for 2013. Given the strong upward trend of warming over 2007 to 2012 it is not surprising that the average of that period is the same (near as damn it) as the cold excursion of 2013. But what I said was that 2013 was a "downward excursion from that trend".

Going back to the issue of Greenland...



The region covered by that is solely ocean with no continental land, merely a few islands, yet it shows a rising trend of temperature, broken by a drop in 2013. The Greenland issue also doesn't apply to the graphs on my blog despite them covering the north of Greenland because I took care to select 'area weighting' before plotting, thus the relatively small area of Greenland ensures it plays a relatively small role in the final result, which is strongly biased towards the demonstrable cooling over the sea ice.

BornFromTheVoid

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1032 on: August 04, 2013, 08:33:01 PM »
No downgrade from the ECM, the storm is still a very strong feature, dipping below 980hPa once more.



This is a very different beast to the storm 10 days ago!

forkyfork

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1033 on: August 04, 2013, 10:47:24 PM »
the upcoming system wasn't projected to be that strong a few days ago

frivolousz21

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1034 on: August 05, 2013, 05:02:19 AM »

With all this in mind, some very high melt rates could be on the cards starting from the middle of next week. A mixture of storm damage, upwelling, export, compaction and general melting could well produce a second period with 7 day losses exceeding 1 million km2.


Fantastic analysis. Top notch.

totally agree.

Wickedly bad pattern oncoming.

Major wind field.  30KTS in Summer is RARE.  Tight gradient.







frivolousz21

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1035 on: August 05, 2013, 06:20:33 AM »


00z GFS bombs it out again.



frivolousz21

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1036 on: August 05, 2013, 10:21:18 AM »


Euro now creating massive gradient.  Almost a Super Bomb.  Thats going to be one hell of a wind fetch with a 35KT max sustained zone somewhere..





frivolousz21

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1037 on: August 05, 2013, 10:34:40 AM »
Euro demolishes the arctic ice.



frivolousz21

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1038 on: August 05, 2013, 12:16:15 PM »
the bomb is going off


Neven

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1039 on: August 05, 2013, 12:28:33 PM »
So soon? No way!

Man, I don't have time for this shit!!!  :(
Il faut cultiver notre jardin

frivolousz21

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1040 on: August 05, 2013, 12:49:43 PM »
Yep.

In 24 hours it's already blowing down through the 980s.

OldLeatherneck

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1041 on: August 05, 2013, 01:06:58 PM »
Yep.

In 24 hours it's already blowing down through the 980s.

How long is this storm going to last?

I can only imagine what the sea state will be with a few days of sustained 30Kt+ winds.  The remaining ice will be tumbled and crushed repeatedly.
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BornFromTheVoid

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1042 on: August 05, 2013, 01:11:02 PM »
An interesting few days coming up anyway

Here's a few charts, from Tuesday to Thursday, showing the main wind directions (white arrows), the general area of the storm (white ovals) and the main damaging wind areas (red lines).

Tuesday


Wednesday


Thursday


Friday


After Friday, high pressure continues to build over the Pacific and Western side of the Arctic, with a general +ve dipole, something that's been largely lacking this melt season.

Sunday


The longer term sees a further +ve dipole and a hint of a return to -ve NAO conditions, which we haven't seen since March.

OldLeatherneck

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1043 on: August 05, 2013, 01:41:43 PM »
An interesting few days coming up anyway

Here's a few charts, from Tuesday to Thursday, showing the main wind directions (white arrows), the general area of the storm (white ovals) and the main damaging wind areas (red lines).

...............After Friday, high pressure continues to build over the Pacific and Western side of the Arctic, with a general +ve dipole, something that's been largely lacking this melt season.

.................

The longer term sees a further +ve dipole and a hint of a return to -ve NAO conditions, which we haven't seen since March.


BFTV,

Thanks for that informative weather forecast!
"Share Your Knowledge.  It's a Way to Achieve Immortality."  ......the Dalai Lama

Neven

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1044 on: August 05, 2013, 02:46:18 PM »
Yes, great stuff, BftV!
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SteveMDFP

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1045 on: August 05, 2013, 06:47:12 PM »
An interesting aspect of the developing weather now is the potential to resume brisk transport out the Fram strait.  As near as I can tell, judging from modis and weather charts, we've had astonishingly little Fram transport since late winter. That looks like its about to change.

Even brisk transport out the Fram at this late stage seems unlikely to have big effects on ultimate September area or extent, and not that much on volume.  But what does get exported may preferentially be some of the oldest, thickest ice left in the arctic.  Another little nail in the arctic coffin.

TerryM

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1046 on: August 05, 2013, 07:30:16 PM »
Friv & BFTV


Thanks so much for the heads up!


Are there any buoys likely to be in the path of this thing? Where it's over FYI the salinity profiles might be skewed until refreeze (winter).


I'm hoping to hear more from both of you as this plays out - some of us (myself at least) are weak on the atmospheric side & can use all the explanatory information you have.


Terry

BornFromTheVoid

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1047 on: August 05, 2013, 08:07:27 PM »
Cheers for the kind words folks. I'll try to post regularly over the next few days but I'm not sure how much time I'll have.

On the meteociel link here http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=6&ech=24 you can look through the individual runs from the 12z GFS ensembles. Even at just 24 hours out, there's is a huge amount of difference on the depth and location of the current storm from one ensemble member to the next, with some already having a powerful <980hPa storm, while others have little more than a shallow low pressure area. The difference can also be seen on the ensemble spread charts, showing the areas of uncertainty at the 500hPa level, which has a large controlling influence on what we see on the ground.


 I assume this is due to a lack of observational data fed into the models from the high latitude area, but whatever the cause, I think it shows that little is quite nailed on yet, other than the fact that there will be a deep low pressure.

Anyway, the 12z ECM is now coming out, and no sign of weakening here


jai mitchell

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1048 on: August 05, 2013, 08:36:54 PM »
This seems interesting, there is a significant push of subtropical moisture moving up from the West Pacific and combining with moisture coming down from the Chukchi over the Aleutians.  This large volume of warmer moist air is then combining in a cutoff low as shown here:

http://www.ssd.noaa.gov/goes/west/nepac/flash-wv.html

Within the next 36 hours this combined subtropical and arctic moisture is being passed northward by the cut-off low as shown here:



within 12 hours after the moisture begins moving northward a new low pressure system sets up in the Bering sea (the dipole?)  which then allows the moisture transport to continue moving farther northward.



Finally, the process of moving subtropical moisture from the West Pacific, up into the Bering Straight and feeding it into the arctic low pressure system is complete:



This is the kind of processes we would expect with a collapsing polar jet stream and a tightening of the polar cell into a tight are of corolis-driven winds moving about the arctic circle and a blending of the ferrell and hadley cells.

frivolousz21

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #1049 on: August 06, 2013, 01:15:08 AM »