Arctic Ice

[J10]

After a couple of very large drops, the figure fell by only 625km2 today to 6485000km2 based on 08/08/08 figures.

The Latest forecasts based on today's values are

for 31st August Min 5,288,518 Midpoint 5,566,076 Max 5,793,699

for the Year Low point Min 4,883,854 Midpoint 5,310,567 Max 5,605,634

The Ice Extent has fallen to 6724844 sq km, based on the 5th August figures, which remains above the 2005 figures but below the 2006 figures.

Based on this and the range of output on the 31st August stands at 5,259,500 (2007 Melting Rate) to 5,913,155 (2006 Melting Rate) with a average of 5,592,380 (based on average Melting Rate over last 5 years.

The Minimum Ice Extent for this year ranges from 4,857,355 to 5,722,170 with an average of 5,336,164.

So on this basis, the minimum ice extent is set to be higher than 2007, There is a chance it will be above the 2005 figure of 5315156, but it is set to be below 2003,2004 and 2006.

Above shows the predictions made on the 6th August as a comparison.

[Iceberg]

There does seem to be fits and starts in the ccurrent figure.

The latest value : 6,335,938 km2 (August 10, 2008)

So another 150,000sq km's this weekend lost.

[doctormog]

I posted this elsewhere (and it should be accurate up to the 10th of August)

Current situation (10th August): Ice extent (in sq km)

2008: 6335938

2007: 5468594

Current situation (1st - 10th August): daily rate of ice melt (mean)

2008: 76500

2007: 79625

Daily rate of melting (10th August to 15th September*) neded to equal 2007 minimum = 57448

For comparison the daily rate of melting from 10th August to 15th September 2007 was 33355

In summary to equal last year's minimum ice extent the daily rate of melt from today until 15th September will need to exceed last year's value by 24093 (sq km/day).

Alternatively at the same rate of melting on average as 2007 to reach the same minimum the ice would need to continue to melt until 26 days after the the 2007 minimum was reached i.e. 11th Ocrober. I believe this would be unprecented.

Of course a commbination of the above (or anywhere between would provide the same result).

In summary the ice rate of melting will need to accelerate rapidly or continue for an unheard of length of time to reach last year's minimum.

*15th September was the date that last year's record ice minimum was reached.

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

[Gray-Wolf]

http://www.nsidc.org/arcticseaicenews/

Well it looks increasingly like , with a continuation of warm waters and stormy seas, that the more sheltered sea ice areas that are currently shedding their ice (at a pace approaching last years record rates) will lead us to an ice min that approaches (or exceeds???) last years min.

As we have all seen ,todays 'new' polar melt season is 'different' in its dynamics (due to the loss of the larger percentage of the old perennial ice) to the 'old' style melt patterns. Not only are we seeing an ever early start to the season but also, due to it's 'single year' nature, a slower start of ice build in late autumn.

It now appears that even an 'average' polar summer can continue the downward trend in ice levels (and the continued loss of perennial ice) due to ever earlier starts to the melt season and then a slower 'rebuild' of pack in autumn. The warmth that the dark water absorbs over mid/late summer is the absolute opposite of the effect an intact perennial pack produces (with a 90% absorption rate over the same area that used to display 90% albedo potentials).

If we ever needed to see why we are 'beyond' the polar 'tipping point' then surely what we will continue to see over the next 4 weeks will amply illustrate it for us.

[Guest Shetland Coastie]

One wonders if the volcanic ash cloud from the recent eruption of Kasatochi will have an impact. AVO (Alaskan Volcanos Observatory) is reporting that the ash cloud from Kasatochi is extensive and covers Sout East Alaska and Western Canada, with another ash cloud over the Gulf of Alaska. Obviously not very significant in global terms but could this have a localised impact on the Arctic, i.e. slowing the rate of melt? Be interesting to see what happens.

Incidentally, all three volcanos that were erupting in the Aleutians have picked up the pace again this morning and these eruptions could run for a while, adding further volcanic ash to the equation.

[Roger J Smith]

Almost tropical air mass has been wedged into north central Canada by an odd blocking pattern, this is fogging up over the high subarctic but still manages to stay 15-17 C, then dries out somewhat as it crosses Baffin Island so 20-23 C there today. Much colder north of Resolute as a low forms just south of there and heads east. This may prevent much further melt for a day or two in the central to western arctic while the Foxe Basin will probably lose much of what is left over there.

This air mass over the eastern arctic was so warm the other day, it was actually warmer at Fort Reliance on Great Slave Lake than much of the United States and southern Canada. Quite unusual -- perhaps you can get a block going over there too and shake off this persistent rain. By the way, the flow around the hemisphere is full of strange anomalies, the 500 mb anomaly west of Ireland must be about -40 dam at the moment, and on the weekend it was about -30 dam over the Great Lakes region, while it is about +30 dam near Baker Lake in northern Canada.

[Android]

http://www.nsidc.org/arcticseaicenews/

Well it looks increasingly like , with a continuation of warm waters and stormy seas, that the more sheltered sea ice areas that are currently shedding their ice (at a pace approaching last years record rates) will lead us to an ice min that approaches (or exceeds???) last years min.

As we have all seen ,todays 'new' polar melt season is 'different' in its dynamics (due to the loss of the larger percentage of the old perennial ice) to the 'old' style melt patterns. Not only are we seeing an ever early start to the season but also, due to it's 'single year' nature, a slower start of ice build in late autumn.

It now appears that even an 'average' polar summer can continue the downward trend in ice levels (and the continued loss of perennial ice) due to ever earlier starts to the melt season and then a slower 'rebuild' of pack in autumn. The warmth that the dark water absorbs over mid/late summer is the absolute opposite of the effect an intact perennial pack produces (with a 90% absorption rate over the same area that used to display 90% albedo potentials).

If we ever needed to see why we are 'beyond' the polar 'tipping point' then surely what we will continue to see over the next 4 weeks will amply illustrate it for us.

Good post. Considering arctic sea ice is a barrier between the upper ocean and lower atmosphere that largely exists throughout the entire year, what effect does removing that barrier have? I am thinking it's a step change. The change in albedo is one step change that you point out, but others I have thought about are evaporation - how is that affected and what effects will that have in turn? Will the reduction of a sea ice barrier allow the wind to mix the upper ocean more? I am no expert on any of this so for all I know these are stupid questions, but I can think of lots of possibile step changes like these. Only need a couple of them to work to get a significant effect.

[J10]

After a couple of very large drops, the figure fell by only 625km2 today to 6485000km2 based on 08/08/08 figures.

The Latest forecasts based on today's values are

for 31st August Min 5,288,518 Midpoint 5,566,076 Max 5,793,699

for the Year Low point Min 4,883,854 Midpoint 5,310,567 Max 5,605,634

Above shows the predictions made on the 6th August as a comparison.

The Latest forecasts based on 11th August's values are

for 31st August Min 5,300,642 Midpoint 5,538,463 Max 5,751,306

for the Year Low point Min 4,894,836 Midpoint 5,284,284 Max 5,565,517

As a reminder the year low point (on these scales) figures in 2005 and 2007 were 5,315,156 and 4,254,531 respectively both in sqkm2.

[osmposm]

....The change in albedo is one step change that you point out, but others I have thought about are evaporation - how is that affected and what effects will that have in turn?......

Off-topic - and call me a pedant and a dinosaur - but can I just say what bliss it is to read a post by someone who not only knows the difference between 'affect' and 'effect', but can be bothered to get them right, too?

Welcome to the bear pit, Android (though actually it's got pretty polite recently after some firm action by senior prefects).

Pedantic Dinosaur aka Ossie

Edited August 13, 2008 by osmposm

[Iceberg]

Far better than my grasp of the english lang. <_<

Quick update.

NW passage open

NW deep water passage very almost open (should be a couple of days).

NE passage very almost open should be the next couple of days.

Svalbard almost ice free around the coast.

[Mondy]

Just wait until the "early nights draw in" up there and the Sun is out for a few hours - just watch the ice extent grow rapidly - winter is coming - sooner rather than later <_<

[doctormog]

Far better than my grasp of the english lang.

Quick update.

NW passage open

NW deep water passage very almost open (should be a couple of days).

NE passage very almost open should be the next couple of days.

Svalbard almost ice free around the coast.

Compare those images with the NSIDC hires data from yesterday:

Which is right?

Edit: See also http://ice-glaces.ec.gc.ca/prods/WIS56CT/2..._0003912829.gif from the Canadian Ice Service (correct as of August 11th)

Edited August 13, 2008 by doctormog

[Iceberg]

The AMSR without a shadow of a doubt doctormog. After speaking to many scientists including Chris Chapman over on CT and through comparisions with modis/aqua real time images.

Your right to question but I don't think you will find an ice scientist that says anything different.

[trevw]

Compare those images with the NSIDC hires data from yesterday:

Which is right?

Edit: See also http://ice-glaces.ec.gc.ca/prods/WIS56CT/2..._0003912829.gif from the Canadian Ice Service (correct as of August 11th)

doesn't the NSIDC image show extent of ice with greater than 15% concentration? This means that areas of 15% concentration sea ice are shown as solid white tending to make the coverage seem greater than it is..

I remember there was a discussion earlier about the leading edge of the nsidc timeseries graph.. over the last few days it has been waggling up and down like a dogs tail!

it's down again today. I know that there is a correction done after the data is first added or something.. What suprises me is the length of the section that 'waggles' is this down to them using a running mean? If so the discrepancy between added results and corrected must be quite large to have that much affect..?

Trev

[doctormog]

The AMSR without a shadow of a doubt doctormog. After speaking to many scientists including Chris Chapman over on CT and through comparisions with modis/aqua real time images.

Your right to question but I don't think you will find an ice scientist that says anything different.

I can't say I've spoken with anyone on CT, but the Canadian Sea Ice data seems very comprehensive and re. the MODIS satellite imagery, the region in question seems to have been shrouded in cloud in recent days and I've struggled to find a clear view - as this is what I would normally base my opinions on I'm left looking at 3 different pictures.

Anyway I'll take your word for it. :lol:

[Gray-Wolf]

I can't say I've spoken with anyone on CT, but the Canadian Sea Ice data seems very comprehensive and re. the MODIS satellite imagery, the region in question seems to have been shrouded in cloud in recent days and I've struggled to find a clear view - as this is what I would normally base my opinions on I'm left looking at 3 different pictures.

Anyway I'll take your word for it. :lol:

As R.J.S. pointed out there are high temps and sea fog up there presently so it will be an 'enlightenment' when the fog clears I'm sure!

[doctormog]

I'm confused by the "high temps up there bit "(not the meaning, the accuracy) Canada's an awfully big place.

There have been high temperatures in some parts of Baffin Island and Nunavut which were largely ice free anyway but much of the Archipelago region has been around average except for northern parts which have been below) for the last few days.

One thing's for sure and that is that there is more ice in the Archipelago/NW Passage region than this time last year.

Edit: If you want an example try Resolute in the heart of the region in question http://www.weatheroffice.gc.ca/city/pages/...7_metric_e.html

Edited August 14, 2008 by doctormog

[Iceberg]

Don't shot the messenger but CT now has the current ice situation still declining rapidly and now officially below the level reached in any previous year except for last year. So we have at least the second lowest ice extent ever recorded according to CT.

Ice melt is still opening the various passages with still worrying signs of multi year ice melt.

As last winter had more ice than the winter before I can easily see this being the year that has melted the most amount of arctic ice, even if a new record minimum is not reached.

[jethro]

I was having a look at Solarcycle24.com last night, according to a post on there, there have been a couple of earthquakes in the Arctic this week; don't know what impact, if any, this would have had on the ice - perhaps fracturing and fragmenting it further? I've tried to access the site to post the link here, but it appears to be down this morning.

[Guest Mike W]

With this almost record breaking ice melt taking place doesn't this sort of kill the idea of the start of global cooling from a weak sun. Surely if were a re startin g to cool you woudln't get record ice melt?

[LadyPakal]

If you stop heating a pan of water, it doesn't immediately cool. Now substitute 'massive oceans' for pan of water.

[Nick L]

Precisely. It isn't going to switch from record low ice to record high ice in one year. I don't think it will reach last year's minimum so therefore it will be an improvement IMO. The past 20 years of warming didn't suddenly happen in one year.

[doctormog]

Don't shot the messenger but CT now has the current ice situation still declining rapidly and now officially below the level reached in any previous year except for last year. So we have at least the second lowest ice extent ever recorded according to CT.

Ice melt is still opening the various passages with still worrying signs of multi year ice melt.

As last winter had more ice than the winter before I can easily see this being the year that has melted the most amount of arctic ice, even if a new record minimum is not reached.

In the same way that last winter saw a record refreeze level?

With the (current) below average temperatures looking set to continue in the Canadian Archipelago region I'd expect low ice loss there in coming days - in contrast N Siberia is stilll anomalously warm so ice exent there is highly likely to continue it's steady decline

For reference and comparison to the last 3 years, the appropximate current ice level (yesterday) was reached on:

3rd August 2007

21st August 2006

16th August 2005

[J10]

The figures that I have been using do not show the figures below show the minimum Ice Extent for each year as follows.

in 2003 to be 6,032,031 sqkm2

in 2004 to be 5,784,688 sqkm2

in 2005 to be 5,315,156 sqkm2

in 2006 to be 5,781,719 sqkm2

in 2007 to be 4,254,531 sqkm2

With the Current Ice Extent 6,071,094 sqkm2.

So on this basis it is above, every one of those past years, although it may well end up lower than end up lower than any year except 2007, which it is likely to remain above substantially.

[Iceberg]

I was careful to say according to CT. Cyrosphere tends to preceed NSIC by a good few weeks.