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Andrew Xnn

2008 was a leap year, so it and 2004 could 1 day ahead of all the rest
depending on how things are calculated.

However, looking at the average daily melt for the month of August, it
is apparent that August 2008 was an exceptional month too.

Patrice Pustavrh

Hi Neven, it is very nice to come to your blog from Ouslund's blog which is indeed interesting blog to watch. I'd like to comment on Patricks correction on my prediction of compactification, because I think we were speaking about two slightly different things. The way wind blows now moves ice from East Siberian Sea towards the centre and further along towards Canadian Archipelago. Of course I was innacurate about serious compactification and Patrick is of course very right that serious compactification cannot occur with this mobility of ice and that we will see a lot of export through that region. However, I think that the a little bit more ice north of Canadian Archipelago and land of course, islands themselves will lead to some sort of compactification. Way below, but I think this will bring the area and extent further down (because ice is thinner than usual while being spread around and area/volume ratio is really low now). Great mobility of ice can bring ice more closely together and with just slight increase in thicknes, which would still be way below normal levels, extent can easily drop to at least 2008 levels. I must admit that I am deliberately not talking about melting. Not because I do not believe that there is no melting or that it is slower like it was in previous years, but just because I am at the present knowledge capable about talking only about ice distribution with reasonable accuracy. And my point is not to feed Watts or Goddard, but just to reveal some variability and that we really need to be careful about interpreting various years results. And finally, if the weather predictions hold for next 14 days, I would not be surprised that extent and area drops will be well above average for this time of year.

Neven

2008 was a leap year, so it and 2004 could 1 day ahead of all the rest
depending on how things are calculated.

Andrew, I in fact compare Julian dates. In my spreadsheet I don't use any February 29th, which means 2008 has a day extra at the end of December. So in a way today's date, August 14th, is compared to August 13th 2008. But both are referred to as Julian day 226.

Patrice, I agree. When I say melt I of course mean 'decrease of sea surface covered with ice', whether this occurs due to melt, transport or compaction. Real melt refers to sea ice volume. CryoSat-2 will tell us more about that.

siili

Sorry to be a nitpick Neven, but since i am an astronomer, Julian Day is in fact something different http://en.wikipedia.org/wiki/Julian_day, what you are using could perhaps be called day number or formaly last three digits of an ordinal date.

Neven

Indeed, siili, thanks for bringing that to my attention.

What I meant was this: August 14 is the 226th day of the year (227th in leap years) in the Gregorian calendar. So I compare this day to the ones in other years. As 2008 was a leap year, August 14th was actually the 227th day of the year. Therefore I compare today with August 13th 2008, which was the 226th day of the year in 2008.

Right, now I have a headache again.

siili

If it will cure your headache, you might as well use the Julian calender at least untill 2100 when it matters next time...

Neven

Siili, you will have to come up with something better. What will I use after 2100?

toby

Thanks for the post, Neven,. I think we are entering an interesting period - almost literally the last quarter. It is hard not see it as a competition and "root" for a side, but when the implications of low extent hit home, I am a bit sickened.

Along with the extreme weather, which has attracted attention worldwide, a low Arctic ice measure might help speed up political action. But how different it was last January when the ice extent was approaching average & a lot of the Northern Hermisphere was having a tough winter The two (last winter & this summer) are not equivalent, however, because a lot of the extreme temperatures and floods have exceeded records, while there were none did last January. I do sense a different tone in the mass media towards climate change, but we know short the attention span is.

Phil263

JAXA reports : -60,781 SIE decreae. Just for the anecdote, exactly the same decrease as for 14 Agust 2008 (at least same day in my calendar :)!

Anu

It takes a very complicated wind pattern to spread out ice floes to create large lakes surrounded by sea ice (look near the Beaufort and Chukchi Seas):
http://img405.imageshack.us/img405/6646/arclatestlarge201008140.png

But it is trivial to create such lakes by melting - the question is, how thick is the remaining, nearby non-melted sea ice ?

In summer 2008, ice mass balance buoys measured bottom melt and surface melt at various locations around the Arctic:
http://www.joss.ucar.edu/events/2009/aon/reports/richter-menge_jackie.pdf
In the Beaufort Sea, where 3.2-m thick ice completely melted by 23 August 2008, with more than 0.85 m of surface melt and 1.77 m of bottom melt measured, the largest amount of melting was measured. On average, they saw 0.47 meters of surface melt and 0.66 meters of bottom melt that summer - so, on average, the warm water melted more ice than the direct sunlight and warm air.

I suspect that huge sheets of sea ice near those "lakes" are close to "running out of thickness" as the summer melt continues...

Chartsgraphs.wordpress.com

It's now 5 straight days of 2010 SIE decrease being > than 2007 values!! 2010 has reduced 2010-2007 gap by 93,300 km^2 in 5 days.

While 2010 - 2007 gap is -676,000 km^2, there are 41 remaining daysl for 2010 to match the 2007 minimum SIE.

Kelly O'Day

Mike

If I may mediate on the subject of Julian Date, it does have a different meaning in the computer context as 'ordinal date' as opposed to astronomical usage. While I'm here I'd like also like to comment on the amazing things happening in the Arctic. I can't help but think that the departure of land-fast ice may have immediate consequences for wildlife in general. I think this might be a more immediate problem than general climate change. The East coast of Greenland is really shedding(?) quite rapidly.

Neven

CT also reports a decrease of 66K in sea ice area.

Kelly, I really don't think 2010 will catch up with 2007. Staying ahead of 2009 is challenging enough as it is. And perhaps, if those highs and lows do enough damage in the right spots, 2008 can be beaten as well. But that's tops for this year, I think.

Neven

After a downward revision yesterday's melt is 63,281 square km. Still in the 60's.

PIPS arrows are looking interesting.

Phil263

SIE barely 40k down today... (Jaxa preliminary)

Phil263

CT also reports an increase of 9 k in SIA ? I cannot really see where this increase would come from as all areas. seem to be losing ice except for a slight uptick in the arctic basin.
I also note on the uni bremen , map, that the holes North of the Beaufort sea have closed up since yesterday which may explain the small decrease in SIE today (?)

Neven

I was expecting a bit more than that. Is that big low between the Kara and Laptev Seas blowing all the ice outward toward Fram Strait?

siili

Second that, but looking at the Jaxa timeseries, the Fram outflow is increasing extent, but then looking at the wind and ice bouy drift maps, i don't think the reall move has started yet. From Amundsens measurments the whole southern Beaufort is full of 10 C warm waters, which is starting to move at the ice guided by the increasing high over the CA.

And thinking about the closing whole, MODIS had a very good day yesterday http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r05c02.2010227.terra

Phil263

in his arctic ice august update #2 , Patrick mentions the possibility for ice floes to be partially covered by see water " swamped ice". I was wondering how that "swamped ice" would register on satellite pictures such as AMSR-E. In other words is it possible that "swamped ice" would have missed, and then when it reemerges it would picked up as ice area, which would explain the increase in SIE /SIA?

Phil263

For the link to Patrick's article on submerged ice floes try here .

Phil263

Have a look at WUWT report on Climate Change day in Australia (That was yesterday). More evidence if any was needed that that site is not about science. In these days of election campaigning, WUWT arcticle actually reads like a conservative ( called "Liberals" in Australia), propaganda piece against climate change action.

Lord Soth

Well we broke the 6 millions sq. km. barrier last night. It still subject to revision, but I dont see a 20K correction in the works.

To keep in the running with 2008; we will need to lose another million sq km in 16 days.

It possible, but we can't have very many more days like yesterday.

With only a month left in the melt season; I think PIPS will be on the money with 4.8 million sq km of slush. This is a remarkable accomplsihment despite July being cool and clowdy.

Kevin McKinney

"More evidence if any was needed. . ."

None needed as far as I'm concerned. It's a pure propaganda operation, as long since revealed by their "chopping and changing"--that is, the incoherence with which the latest anti-mainstream factoid or crank theory is embraced and celebrated, regardless of how incompatible it may be with yesterday's "theory." (Or with anything else, for that matter.)

They've been corporately calling black "white" over there so long that I doubt there's any remaining ability to distinguish the two.

FrankD

Check out the Beaufort Sea on todays MODIS (day 227).

Very little icepack, just a huge area of "milk". Personally, I think CT's extent estimate is generous, for that area at least.

Lord Soth

That milk like appearance is caused when the individual chunks of ice are much smaller than the resolution of the imaging. Those flows are probably anywhere from a few meters to few 10 of meters across; and are in the last stage of melting out.

Phil263

To keep in the running with 2008; we will need to lose another million sq km in 16 days.
I doubt very much that 2010 is still in the race for a minimum under or even comparable to 2008.
Yes today 2010 SIE is still barely below that of 2008 but it will probably not be after the new update. SIA has been going up over the last three days ( see CT ) and is now almost 400 k greater than 2008. If SIA is predictor of SIE, this means that the melt in the next few weeks is going to be very reduced.
In my view, 2010 will have a big challenge keeping up with 2009; actually it looks more like 2006 than 2009!
I have been reading the posts and comments with great interest as i do not know much about ice science. I have read that the weather has a big influence, but now the weather is favourabble so there must be some other variables. The NSIDC mentioned in its update in early July that there was mo thick ice this year and may be this is the reason why we are seeing such low rates of SIE decrease. I am here to learn and I have learnt a lot from this site, but obvioulsy the science on this is not settled,

Artful Dodger

FrankD, the latest Arctic SST map confirms the extent of the sea ice loss in the Beaufort Sea and Central Basin:
http://polar.ncep.noaa.gov/sst/ophi/color_sst_NPS_ophi0.png

Kevin McKinney

Welcome back, Dodger.

Phil, don't be too sure yet. If there's anything I've learned about the sea ice, it is that it is very prone to make fools of all of us who dare to traffic in predictions--especially short-term ones! The weather just turned; let's see what happens after a few more days.

siili

Jaxas preliminary numbers are in, at 5910781km^2, 70625 less.

Two interesting things could be noted, the history of (two-day averages) losses is about 60k,60k,40k and 70k, and if 60k was the true 3 days ago, 120k should be the unsmooth loss for today.

The other noteworthy thing is that in the preliminary Jaxa-images there is a rather big artifact in the choppy sees of the deep low south of the iceedge which will be corrected in the update later today, if that is counted in the extent number, well...

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