During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good explanation of what sea ice extent is in their FAQ. I also look at other things like sea ice area, concentration, volume, temperature and weather forecasts, anything that can be of particular interest. Check out the Arctic sea ice graph webpage for daily updated graphs, maps and live webcam images.
July 9th 2011
Last week I wrote in the conclusion of SIE 2011 update 10:
I think we are going to see above average melting the coming week, perhaps even some century breaks.
This is exactly what has come about. Not that it was hard to predict, as everything was pointing to a big high-pressure area stabilizing over the central Arctic. In fact, I even was a bit too cautious/cowardly. The first 8 days of July saw 5 century breaks, of which 3 made it into the top 10 of biggest daily extent decreases (h/t Lord Soth).
As the sun keeps burning hot and long, its rays reaching much of the ice in the Arctic Basin, 2011 is tracking 2007 and 2009, the only years having an average daily extent decrease of over 100,000 square km in the first 8 days of July. And although that high-pressure guaranteed a substantial drop in extent, there was and still is plenty to learn and observe.
Of course, dominating high-pressure areas are a prerequisite for mega-melt, but how much do details in distribution matter? The Dipole Anomaly requires a high-pressure area over the Canadian Archipelago, extending to Greenland. For the Beaufort Gyre to gyre the high-pressure should be ideally over the Beaufort Sea (hence the name I guess). But this current high-pressure area is very large and over the centre of the Arctic Basin, almost directly over the North Pole, which prohibits strong ice export through Fram Strait, to name a thing. Still the extent decreases fast.
What will the effect of all this insolation in the middle of the ice pack be as we enter the second halftime of the melting season? And of course the million dollar question: will 2011 keep tracking 2007? How long is this high going to dominate?
Sea ice extent (SIE)
Here's the current IJIS SIE graph:

2011 decided to forge ahead, leaving 2010 in the dust and even increasing the lead over 2007. This is quite amazing as 2007 had a stunning run of century breaks in this first part of July. I guess I don't have to explain that this means 2011 is currently leading in the race. 2010 is finished for the rest of the month and will fall back quickly. The same goes for 2006, albeit to a lesser extent. 2009 will start to put up a fight towards the end of the month. But right now it's between 2011 and mighty 2007.
The current difference between 2011 and the other years is as follows:
Recent Comments