NSIDC Arctic sea ice news mid-August 2011

It's been out for a couple of days already - and I'm a bit slow - but I want to give it some attention nevertheless: Another mid-month analysis from the National Snow and Ice Data Center. A few snippets, starting with the last bit which I found particularly interesting (Rob Dekker already told us about this buoy site a while back):

 

Summer melt and sea ice thickness
Data indicate that the Arctic ice cover continues to thin. Sea ice thickness is also an indicator of the health of the ice cover; thick ice is resistant to melt. Specialized buoys managed by the U.S. Army Cold Regions Research and Engineering Laboratory help supplement limited satellite measurements of sea ice thickness. The buoys provide accurate data at specific locations, and can tell us whether thickness changes are due to surface melt, melt at the bottom of the ice floe, or ice growth. These buoys are deployed on thick multiyear ice, which provide long-lasting, stable platforms.

Data from six of these buoys through July 20 show that this year, the ice surface is melting faster than the underside of the ice. As the sun starts to sink on the horizon, surface melt will slow. However, ocean waters warmed during the summer will continue to melt the ice from below, reducing ice thickness and extent into September.

(...)

After a period of slow melt from late July through early August, Arctic ice extent is again declining at a brisk pace, but remains higher than for 2007, the record low year. Data also indicate continued thinning of the ice. With about a month left in the sea ice melt season, the amount of further ice loss will depend mostly on weather patterns. 

Overview of conditions
As of August 14, 2011, Arctic sea ice extent was 5.56 million square kilometers (2.15 million square miles), 2.11 million square kilometers (815,000 square miles) below the 1979 to 2000 average for that day, and 220,000 square kilometers (84,900 square miles) above the extent on that day in 2007.

Sea ice is low across almost all of the Arctic, with the exception of some areas of the East Greenland Sea. It is exceptionally low in the Laptev and Kara Sea areas.

(...)

Arctic sea ice loss slowed down in late July through early August; then over the past week, the rate of ice loss sped up. At present there is more ice than at the same time in 2007, which saw the record minimum September extent.

(...)

A change in the weather
During early summer, a high-pressure cell persisted over the northern Beaufort Sea, promoting ice loss. This weather pattern broke down toward the end of July, slowing ice loss but spreading out the ice pack, making it thinner on average. The weather has now changed again, bringing another high-pressure pattern. Winds associated with this pressure pattern generally bring warm temperatures, and tend to push the ice together and reduce overall extent. In the Kara Sea, the combination of a high-pressure cell with low pressure to the west has resulted in strong northward ice movement, pushing the ice pack away from the coast and reducing ice extent. The same weather pattern is also increasing the movement of ice out of Fram Strait, between Greenland and Spitsbergen.

 

Comments

[Seke Rob]

Did a chart on stepped Ice Off days similar to the stacked bar chart for extent.

http://i137.photobucket.com/albums/q210/Sekerob/Climate/Arctic_SIA_Days_Million_Decline_Steps.png

Something is weird after 1996 (think that year was specifically mentioned some days ago on this blog, but forgot the 'what'). It's almost as if the signal is 'could not care less about the weather as of the mid 90's

Did look at acute daily step changes, but these are randomly appearing from 1984. Am simply not aware of the history v.v. satellite platform changes or algorithms that smooth differently during various parts of the melt season. CO2 is up, it always is, except the NH summer season, till when leaves start falling of trees. We need winter hardy, fast growing, long lived evergreens... lots of it as other sequestration is most improbable to ever put a dent in the upward curve.

[Bob Wallace]

The seven day (ending on 8/18) average loss is 70,580 for this year. In 2007 it was 43,192.

Except for a couple of days when losses hit 60k in 2007 and pulled the average up to 51k, 2007 average loses stayed in the middle 40s and then dropped toward zero from here on out.

It's looking like there's a lot of 'momentum' left in this ice. The sun has stopped inputting energy but the condition of the ice and stored heat seem like they could push the bottom to a new level.

I'm guessing that the next week will tell us the outcome. Unless there's a steep drop off in the next few days then we're going to see a coasting past 2007.

[Bob Wallace]

Whether a new record is set this year largely depends on what happens on the Pacific side. It's ice in the East Siberian along with some additional ice in adjacent areas which are holding the numbers high.

But on the Atlantic side things are quite interesting (at least to me). If you add together the remaining ice in the Central Arctic Basin and the Greenland Sea (working from eyeballing the regional maps) there was about 3.41 million km^2 total ice in 2007 and 3.38 million km^2 in 2011. Not a lot of difference, but the distribution has shifted a bit to the Greenland, taking the Central to what I would assume a record low.

Then, sitting along side that extra ice snuggling up to Greenland there's a band of ~3C water.

I'm guessing an obvious record melt in this portion of the Arctic.

(I tried posting this on the #16 thread where it better fit, but for some reason it wouldn't 'take'.)

[Patrick McNulty]

My idea can weaken a hurricane and so it will also restore Arctic Ice. Go here to find out how.

http://www.wunderground.com/blog/cyclonebuster/comment.html?entrynum=126