Arctic Ice Discussion

[4wd]

http://rapidfire.sci...1102.terra.250m

I feel the next two days will see the end of yon ice bridge?

http://ocean.dmi.dk/arctic/images/MODIS/Kane/201104270103.ASAR.jpg

Ice bridge still looks unchanged.

Very much so songster! I , for one ,did not feel it had such integrity after the initial collapse but ....

Tout change, mais tout reste le même

[Gray-Wolf]

Still awaiting MODIS confirmation , 4wd, but we seem to have lost some of the bridge today?

The C.T. ice extent plots suggest a lot of 'stretching of the central pack now the B. Gyre has sprung into life but it will be quite a while before those 80% sections drop below 15% but it does not look very pretty for sure. If you spend a couple of days worth of images (250m scale) you can see how ragged the pack looks already and the more fragmented the more surface area is exposed to the ocean and the faster it ablates. Hold onto your hat's guys! late may/early June look precipitous (loss wise on the graphs). I suggested early on that we would see a new record for rate of ice loss this year and it appears that I was not wrong!

It appears that the cold over Canada/Greenland is now letting up and even the N.Pole cam jumped from -20c internal temps to +2c temps yesterday so even the central areas seem to be exchanging winter for spring? If the Di-pole persists then that early summer sun will play havoc with such a skimpy pack for sure. Not long to wait though as the days rapidly lengthen to their max over the next 8 weeks.

[songster]

Um, no? No change on ASAR or MODIS that I can see. What makes you think there might be?

[Gray-Wolf]

http://rapidfire.sci.gsfc.nasa.gov/realtime/single.php?2011118/crefl2_143.A2011118141000-2011118141500.250m.jpg

Sorry songster , you are correct. As I said I needed a few more images to look at before confirming. The above image appeared (to me) to deeper scalloping on the Canadian /Baffin side but the latest ASAR sees no change from before the 21st. Can't be long though?

The JAXA figures since the 25th have stepped up a pace with todays prelim showing a 65k loss. How long before we start hitting a regular 100k+ (my guess would be mid April with record loss rates by mid June?).

Thanks again for the 'quality control' songster!

[Geordiesnow]

As a complete novice of the Arctic Sea ice, I'm interested to know what a "di-pole" is, going by the posts, its a weather set up that occurs in the Arctic which has a negative affect on the sea ice but how do I know when the charts are showing it?

[Gray-Wolf]

Arctic dipole anomaly

The Arctic dipole anomaly is a pressure pattern characterized by high pressure on the arctic regions of North America, and a low pressure on the Eurasia region.^[1] This pattern sometimes replaces the Arctic oscillation and the North Atlantic Oscillation.^[2] It was observed for the first time in the first decade of 2000s and is perhaps linked to recent climate change.^[3] The Arctic dipole lets more southern winds into the Arctic ocean resulting in more ice melting.^[1] The summer 2007 event played a big role in the record low sea ice extent which was recorded in September.^[2] The Arctic dipole has also been linked to drier winters in Northern Europe and colder winters in East Asia and North America.^[2]

^from;

^{http://en.wikipedia...._dipole_anomaly}

Edited April 29, 2011 by Gray-Wolf

[Gray-Wolf]

Another 67.5k on the first sweep of the JAXA extent and you can see that this puts quite a steep line on the graph;

http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm

which is now set to continue as we enter the early phase of melt season proper. This is only the peripheral ice melting out though.

[Geordiesnow]

Thanks for that GW, looking at the charts, we are seeing part of that set up showing but too me, it looks like the majority of the Arctic is under low pressure condition thus the colder uppers gain strength again which can only be a good thing for the Sea Ice across the body of the Arctic?

Regarding the JAXA graphs, does the 1st update has the lowest figure of the day and then when the 2nd update arrives, the figure actually goes up, I know this is normally the case but i'm sure yesterday's update had the opposite happening so I was wondering if its the opposite during the summer melt season where the 2nd update figure goes down even more than the first update?

[songster]

Lately JAXA has been having several updates a day, and quite wide swings between updates. I believe they had to move their data analysis to another site after the tsunami, so it's possible the processing algorithms are less streamlined than last year.

Melt this year is progressing only slightly slower than last year despite the fact that Canada has been cold and Hudson Bay / Strait hasn't started melting yet. Once these areas do start melting (and they will, since they're fully seasonal), the overall figures will be in for a world of hurt.

[Gray-Wolf]

I'm also worried that ,as with 97' in the world of global temps, 07' will be viewed as some kind of 'benchmark' for ice loss and we will continue to hear tales of 'recovery' every year that does not match/excede that exceptional low?

07' was a shocker but since then we have lost our paleocryistic 'backbone' to the Arctic pack (the only bit that survived the 07' melt) so we face the prospect of only having bay ice and bits to the north of Greenland remaining if we ever run into the 07' synoptic again.

After 07' we were told that those synoptics arrive every 7 to 20 years and so , to me ,we are playing a waiting game until our first 'fully seasonal' Arctic pack. With ice thickness so thin and 'average summer' synoptics leading to us us near matching the 07' low how close are we to the 1 million min even without an 07' 'Perfect Storm'?

For the past 4 winters we have had tales of 'recovery' and I have been chastened for my bleak outlooks only to see 'recovery' fade into the bleak forecasts I made.

This year I have the bleakest forecast yet (with my 3.5 million min) yet privately fear that it will be worse than that (I am moderating my tome as the situation worsens?).

I do wonder though at who will be telling me that "You've got what you wanted now!" when the pack does arrive at sub 1 million at summers end ( some folk can't resist shooting the messenger) yet every person (I know) who shares a similar understanding to my own would dearly wish for thier dire outlook to be wrong and for a real 'recovery' to be just around the corner!

[stewfox]

do wonder though at who will be telling me that "You've got what you wanted now!" when the pack does arrive at sub 1 million at summers end ( some folk can't resist shooting the messenger) yet every person (I know) who shares a similar understanding to my own would dearly wish for thier dire outlook to be wrong and for a real 'recovery' to be just around the corner!

Apart from more oil drilling more tourism for the region ( ships up in the artic etc)

Why would it be dire ?

We worry that a lump of ice may melt more in the summer.

If Greenland ice sheets start to go thats a different story

[noggin]

I'm also worried that ,as with 97' in the world of global temps, 07' will be viewed as some kind of 'benchmark' for ice loss and we will continue to hear tales of 'recovery' every year that does not match/excede that exceptional low?

Hi Wolfie....hope you are going along OK!

I have to agree with you in principle on this. These sorts of comparisons are, indeed, odious. For me, it's when the "current" CET anomalies are compared with 1961-1990. It just makes no sense.

Like my old driving instructor used to say "don't compare peas and carrots".

[knocker]

If Greenland ice sheets start to go thats a different story

I thought they already had.

Analyses of remote sensing data, surface observations and output from a regional atmosphere model point to new records in 2010 for surface melt and albedo, runoff, the number of days when bare ice is exposed and surface mass balance of the Greenland ice sheet, especially over its west and southwest regions. Early melt onset in spring, triggered by above-normal near-surface air temperatures, contributed to accelerated snowpack metamorphism and premature bare ice exposure, rapidly reducing the surface albedo. Warm conditions persisted through summer, with the positive albedo feedback mechanism being a major contributor to large negative surface mass balance anomalies. Summer snowfall was below average. This helped to maintain low albedo through the 2010 melting season, which also lasted longer than usual.

http://iopscience.iop.org/1748-9326/6/1/014005/pdf/1748-9326_6_1_014005.pdf

[stewfox]

I thought they already had.

Analyses of remote sensing data, surface observations and output from a regional atmosphere model point to new records in 2010 for surface melt and albedo, runoff, the number of days when bare ice is exposed and surface mass balance of the Greenland ice sheet, especially over its west and southwest regions. Early melt onset in spring, triggered by above-normal near-surface air temperatures, contributed to accelerated snowpack metamorphism and premature bare ice exposure, rapidly reducing the surface albedo. Warm conditions persisted through summer, with the positive albedo feedback mechanism being a major contributor to large negative surface mass balance anomalies. Summer snowfall was below average. This helped to maintain low albedo through the 2010 melting season, which also lasted longer than usual.

http://iopscience.io..._6_1_014005.pdf

I meant sustained real losses rather then some seasonal variations

[jethro]

A new ice core has been drilled and analysed, here is the latest info on the expected future of the Greenland ice sheet.

The abstract:

The total extent of ice melt on the Greenland ice sheet has been increasing during the last three decades. The melt extent observed in 2007 in particular was the greatest on record according to several satellite-derived records of total Greenland melt extent. Total annual observed melt extent across the Greenland ice sheet has been shown to be strongly related to summer temperature measurements from stations located along Greenland's coast, as well as to variations in atmospheric circulation across the North Atlantic. We make use of these relationships along with historical temperature and circulation observations to develop a near-continuous 226 year reconstructed history of annual Greenland melt extent dating from 2009 back into the late eighteenth century. We find that the recent period of high-melt extent is similar in magnitude but, thus far, shorter in duration, than a period of high melt lasting from the early 1920s through the early 1960s. The greatest melt extent over the last 2 1/4 centuries occurred in 2007; however, this value is not statistically significantly different from the reconstructed melt extent during 20 other melt seasons, primarily during 1923–1961.

Full paper:

https://events.icecu...nId=7&confId=34

http://www.worldclim...nland-ice-melt/

[Gray-Wolf]

A new ice core has been drilled and analysed, here is the latest info on the expected future of the Greenland ice sheet.

The abstract:

The total extent of ice melt on the Greenland ice sheet has been increasing during the last three decades. The melt extent observed in 2007 in particular was the greatest on record according to several satellite-derived records of total Greenland melt extent. Total annual observed melt extent across the Greenland ice sheet has been shown to be strongly related to summer temperature measurements from stations located along Greenland's coast, as well as to variations in atmospheric circulation across the North Atlantic. We make use of these relationships along with historical temperature and circulation observations to develop a near-continuous 226 year reconstructed history of annual Greenland melt extent dating from 2009 back into the late eighteenth century. We find that the recent period of high-melt extent is similar in magnitude but, thus far, shorter in duration, than a period of high melt lasting from the early 1920s through the early 1960s. The greatest melt extent over the last 2 1/4 centuries occurred in 2007; however, this value is not statistically significantly different from the reconstructed melt extent during 20 other melt seasons, primarily during 1923–1961.

Full paper:

https://events.icecu...nId=7&confId=34

http://www.worldclim...nland-ice-melt/

Seeing as last years melt exceeded 07' it's a pity the study didn't 'stitch' this on as if 07' is as sig. as they say then 10' and 07' show us how different things are now compared to the pre globally cooled era. I suspect that the Arctic 'long cycle' (60 to 80 years) also plays a part in this as this to must have an element of Atlantic circulation patterns in it?

A pre adjustment 100k loss yesterday in the IJIS extent plot (112k) dropping us down to 3rd lowest with a lot of melt to come now we are in AO-ve (for the first time in a long while?).

With temps now 'normalising on the Greenland/C.A. sectors we can expect this area to now start its melt in earnest (and the loss of the Nares ice bridge over the next few days?). I feel that we will find extent in the lowest position by mid May (looking at Bering and the Siberian sectors) and do not see this position altering then for the rest of summer?

[BornFromTheVoid]

Seems we've lost very little the last few days with even a modest gain in extent for today, which I thought must be quite odd for May. But when I checked back over the old figures, it turns out it's not unusual at all. Here are the number of days with daily extent gains in May going back to 79

Year Gains

79 - 6

80 - 0

81 - 4

82 - 2

83 - 3

84 - 6

85 - 3

86 - 3

87 - 4

88 - 0

89 - 9

90 - 6

91 - 5

92 - 6

93 - 6

94 - 4

95 - 3

96 - 7

97 - 5

98 - 5

99 - 5

00 - 7

01 - 4

02 - 8

03 - 0

04 - 4

05 - 1

06 - 0

07 - 1

08 - 1

09 - 0

10 - 0

Twould appear that only in recent years have transient daily gains in May become a rarity, I'm sure the reasons behind that could be argued over though :lol:

Another thing to note, is that on CT it appears that we're nearing the longest period on record where global sea ice area has average over 1 million km2 below average, so something to keep an eye on.

[Gray-Wolf]

Try again!

http://rapidfire.sci.gsfc.nasa.gov/realtime/single.php?2011129/crefl1_143.A2011129015000-2011129015500.250m.jpg

this am's view of the Nares 'Ice Bridge'

http://rapidfire.sci.gsfc.nasa.gov/realtime/single.php?2011129/crefl2_143.A2011129135000-2011129135500.250m.jpg

and this pm's view of the same.

It finally appears that the front of the ice bridge is crumbling and so I would expect the rest to fail over the coming week (but then I said as much on April 28th and it has held firm since?).

Still a worrying amount of open water to the NE of Greenland and off the Siberian coast though not enough to 'trip' the 15% or less criteria . I would expect a very rapid decline once the melt is in full swing (as this ice succumbs) through late may/June.

Something to watch?

[BornFromTheVoid]

Try again!

http://rapidfire.sci.gsfc.nasa.gov/realtime/single.php?2011129/crefl1_143.A2011129015000-2011129015500.250m.jpg

this am's view of the Nares 'Ice Bridge'

http://rapidfire.sci.gsfc.nasa.gov/realtime/single.php?2011129/crefl2_143.A2011129135000-2011129135500.250m.jpg

and this pm's view of the same.

It finally appears that the front of the ice bridge is crumbling and so I would expect the rest to fail over the coming week (but then I said as much on April 28th and it has held firm since?).

Still a worrying amount of open water to the NE of Greenland and off the Siberian coast though not enough to 'trip' the 15% or less criteria . I would expect a very rapid decline once the melt is in full swing (as this ice succumbs) through late may/June.

Something to watch?

I dunno GW, there has been bits and pieces breaking since it first formed and a sizable chunk came off the Northern part only this day last week, so I think we really don't know when it will give way, just that it will most likely in the next few weeks.

When comparing to last year it would seem we're doing a bit better in general, but especially across the western Archipelago and along the Russian coast. Plenty of time for things to change, but I think it's at least a positive start to the melt season. When we start getting the first +0C 850hPa temps into the Arctic it will give us a better idea of the packs strength compared to recent years.

[Gray-Wolf]

I'd have to agree with you BFTV, a much slower pace to the start of the season. My concern remains the youth and thickness of the pack and ,as you point out, the test is summer proper?

As for the Russian side? the land based snow cover cleared off early and , cloud allowing, MODIS shows a lot of fragmentation there? Any land originated winds will eat away at the upper surface of the pack there so I do not see this sector as potentially surviving melt (though only an assumption you understand?).

[Gray-Wolf]

looking back at last years (09/10) winter thickness plots the russian side of the basin had some thick ice which took all summer to melt. This past winter did not see a repeat of this with late re-freeze and warm temps. As such the Russian side of the Basin will be the first to melt out this spring with the Alaskan/Canadian/Greenland side following on.

Still a lot of wide leads across the high pole and , I believe, we can see one open on the North Pole web cam 1;

no disruption in the foreground

lead begings to open

lead across the middle of left of image

If this is a lead (with open water) and not a pressure ridge/over riding then the freeboard shown on the above does not look very deep so the ice itself cannot be very deep?

the bright white above the band of dark is what I see as freeboard.

The 'average' I've seen mooted is 2.5m (across the Basin) which is not enough to gaurentee safe passage over the summer months for the ice with only 'favourable weather conditions' sparing such ice from melt.

It looks to be a very interesting and different melt this season (I believe) with the ice possibly breaking up into individual 'ice islands' across the basin by Aug (as we briefly saw last summer). Any 'Indian summer' could see a very low Sept min indeed if these 'ice islands' do form as the surrounding 'dark water' erodes thier mass.

Edited May 13, 2011 by Gray-Wolf

[songster]

If this is a lead (with open water) and not a pressure ridge/over riding then the freeboard shown on the above does not look very deep so the ice itself cannot be very deep?

Oh come on! There is nothing of a known size anywhere near the feature that could give you any perspective / proportion to base that on. Remember that only 1/10 is freeboard: are you seriously trying to eyeball the difference between 15cm and 40cm at an unknown difference from the camera, with no scale marker, when you can't even see how much of the thickness is ice and how much is snow?

Edited May 13, 2011 by songster

[Gray-Wolf]

Oh come on! There is nothing of a known size anywhere near the feature that could give you any perspective / proportion to base that on. Remember that only 1/10 is freeboard: are you seriously trying to eyeball the difference between 15cm and 40cm at an unknown difference from the camera, with no scale marker, when you can't even see how much of the thickness is ice and how much is snow?

Sorry if you feel this a pointless exercise songster? The past month the CT images have shown near polynya's around the pole area as thin ice gets pulled/pushed around by the wind/currents. I've seen this occur in areas you'd expect such 'stretching' to occur (the approach to the Fram straight being one) but never at the pole and never in April/May? The 'Wokingham Satellite' ( http://www.woksat.info/wos.html ) site has also show open leads across the pole throughout the winter and last years North pole Cam exited the Basin in Jan (along with all the ice that was at the pole when it was deployed last spring) so we know that this section of the Arctic ocean is young ice formed over at the Bering end of the Beaufort sea last Autumn and shunted to the pole on the trans Arctic Current (with a little help from the Beaufort Gyre on the way!).Anyhows , I find it of interest and though only 'eyeballing' the lead does not seem to expose a very substantial pack (to my eye that is) but time ,as ever, will reveal all.

With melt now occuring we will soon know how skimpy (or not?) the pack is this year as the areas of fragmented ice melt out (looks like the Russian side will not endure as well as it did last year with little or no thick ice shown there?) If this ice is as thin as the 2.5m figure I've been hearing about then this should be quite a rapid process come mid June onward but ,as ever, weather will play its part in this. I ,for one, did not expect winter to be overlong on the Canadian/Greenland side of the Basin so that is one plus we can factor in.

As for the NW Passage I wonder if we will be waiting for the McClure straight to break up (at the Alaskan end) this year or will Beaufort have cleared enough to allow it's breakup before the 'indent' (now working it's way towards Viscount Melville Sound) makes it through to it's location?

All in all a slow start to the melt season (a melt season that has a lot of folk quite jittery..... me included!) If nothing else it will help to highlight how ice 'thickness' ,and not 'extent' is the thing we need to focus on. Even with a 'slow' start to the season the amount of 'thin ice' will surely make an impact as we trawl into 'high summer' in the Arctic?

[Gray-Wolf]

A preliminary evaluation of the test results shows that the one-year sea ice in the Beaufort Sea (North of Canada/Alaska) about 20-30 cm thinner is this year than in the past two years. The ice thickness was 2009 at an average of 1.7 meters, 2010 1.6 metres and 2011 at 1.4 meters. "I would expect that this thin one-year sea ice not survives the melting period in the summer", estimates a Dr. Stefan Hendricks the situation. In a few weeks, his colleagues from the Group of sea ice at the Alfred-Wegener-Institut will 2011 present their model calculations for the sea ice minimum, into the now collected data.

You'll need a translator but the above is culled from ;

http://www.awi.de/de/aktuelles_und_presse/pressemitteilungen/detail/item/polar_5_uebersetzung_noch_einfuegen/?cHash=9d78588fc3dfaa962a0d5250e1409adb

with a rough translation.

Beaufort (esp. South Beaufort) was another area where the Arctic ocean transport would create thick , Paleocrystic ice. This is where prof Barber saw the demise of one such floe in Sept ,09' (and saw a lot of 'rotten ice'?) We can see from the above that the loss of this 'Arctic Backbone' has had a dramatic effect on the average ice thickness in the region.

If ice of 2.5m can melt out , in-situ, over an 'average summer' how do we feel the ice on this transept will fare this year?

Once upon a time the ice in S.Beaufort/ N.Canadian Archipelago/N. Greenland used to be the 'nursery' for all the Paleocrystic ice in the basin (with the Beaufort Gyre and Trans polar Current then distributing this ice throughout the basin) In the 1940's ice islands were spotted here and tracked as they drifted through the basin (once such immense floes where thought to be 'Land' and plotted on charts!) .....somehow I don't think folk could find such in the basin today?.....even the ice sheets on the Ward Hunt side of Ellesmere Island no longer have such ice amounts to collapse (probable method for these islands formation) anymore.

The demise of the Arctic's ability to form/keep this ice is crux to this years ice and its ability to 'ride the storm'. With ice now taking 18 months from formation to exit (instead of 7 years!) I have to wonder at the Arctic falling into another 'rythm' of being? The loss of the Paleocryistic

The above study was to help 'calibrate' the Cryosat2 sat. so surely the data from there will be incorporated in some of the major sites soon? (C.T. ,IJIS,Bremen, NSIDC etc)?

Edited May 14, 2011 by Gray-Wolf

[Iceberg]

Ready for the new record breaking ice melt summer GW, looks about to start......