NSIDC Arctic sea ice news June 2010

The National Snow and Ice Data Centre has just released its June analysis of Arctic conditions in the past month. Here are some excerpts:

Arctic sea ice extent averaged 10.87 million square kilometers (4.20 million square miles) for the month of June, 1.29 million square kilometers (498,000 square miles) below the 1979 to 2000 average and 190,000 square kilometers (73,000 square miles) below the previous record low for the month of 11.06 million square kilometers (4.27 million square miles), set in 2006. In June, ice extent declined by 88,000 kilometers (34,000 square miles) per day, more than 50% greater than the average rate of 53,000 kilometers (20,000 square miles) per day. This rate of decline is the fastest measured for June.

During June, ice extent was below average everywhere except in the East Greenland Sea, where it was near average.

(...)

Weather conditions, atmospheric patterns, and cloud cover over the next month will play a major role in determining whether the 2010 sea ice decline tracks at a level similar to 2007, or more like 2006. Although ice extent was greater in June 2007 than June 2006, in July 2007 the ice loss rate accelerated. That fast decline led up to the record low ice extent of September 2007.

However, it would not be surprising to see the rate of ice loss slow in coming weeks as the melt process starts to encounter thicker, second and third year ice in the central Arctic Ocean. Loss of ice has already slowed in the Beaufort and Chukchi Seas due to the tongue of thicker, older ice in the region noted in our April update.

(...)

The Arctic dipole anomaly

The record low ice extent of September 2007 was influenced by a persistent atmospheric pressure pattern called the summer Arctic dipole anomaly (DA). The DA features unusually high pressure centered over the northern Beaufort Sea and unusually low pressure centered over the Kara Sea, along the Eurasian coast. In accord with Buys Ballot's Law, this pattern causes winds to blow from the south along the Siberian coast, helping to push ice away from the coast and favoring strong melt. The DA pattern also promotes northerly winds in the Fram Strait region, helping to flush ice out of the Arctic Ocean into the North Atlantic. The DA pattern may also favor the import of warm ocean waters from the North Pacific that hastens ice melt.

June 2010 saw the return of the DA, but with the pressure centers shifted slightly compared to summer 2007. As a result, winds along the Siberian coastal sector are blowing more from the east rather than from the south. Whether or not the DA pattern persists through the rest of summer will bear strongly on whether a new record low in ice extent is set in September 2010.

Here's the graph:

Read the whole summary here.

Comments

[Lord Soth]

It is interesting that the NSIDC mention that the melt may slow due to encountering second, third and older ice, which I have mention in previous posts.

I disagree about weather conditions will determine if we will mirror 2007 with a record ice melt or return to the 2006 curve. There was a lot more thicker ice in 2006, so I believe that we will see 2007 overtake 2010 for a few weeks, but 2010 taking the lead again in August.

Now the daily ice loss on a daily basis has been very interesting. One day we get a hair breath from a 100,000 sq km loss, the next day we get 34,000 sq km loss. There has been a large amount of variability in daily ice loss since the 30th, too much for normal variation.

Theories on why we are getting such wild fluctuations are welcome.

[Gneiss]

"Theories on why we are getting such wild fluctuations are welcome."

Could they be an artifact of cloud cover? Or a real effect from winds? Just guessing.

Does anyone here know what's up with PIOMAS -- is it broken? The website started out with frequent updates, but now they are rare (last one June 18).

[Neven]

Theories on why we are getting such wild fluctuations are welcome.

Melt ponds? CT has been showing some of those yellow-orange swathes again in the past few days.

One other (small) thing is that the ice bridge in Melville Sound is slowly falling apart, but this counter-intuitively seems to lead to sea ice area gain in the Canadian Archipelago.

[Neven]

Gneiss, I don't know of this has something to do with it but over on WUWT I read this by Charles Wilson:

But since May there hasn’t been any new Laser Data – - – from the central Basin.
IceBridge Airplanes aren’t flying over the Sea Ice anymore.
SO – - Piomas is like a cripple — albeit there are more ship measurements now, but they are FAR FROM THE CENTER.

[Gas Glo]

Gniss, I assume you read the text which says they changed the frequency of updates from a few days to "generated at approximately two-weekly intervals". Yes it is more than two weeks since 18th June, but not greatly more.

[Thomas Woodruff]

FWIW,

I think the low rate of ice retreat lately is due to the weakening of the Beaufort Gyre (BG). If one believes the CT front page map, we can see that concentration is decreasing along the Transpolar Drift. As the BG reverses we will see lots of previously consolidated areas (incl. the East Siberia Sea) become less so. This acts to increase extent. However loosening up this consolidated pack ice may very well lead to much faster melting later in the season.

[Account Deleted]

The latest Aqua image shows new cracks in the block of ice blocking the NWP passage - both in the McClure strait (where it has been breaking up all week) and at the top where it enters the Melville sound. http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r04c02.2010188.aqua.500m

The Terra images aren't very clear.