The cold, cloudy and calm conditions of the past weeks have made themselves felt in the volume numbers as well. Where 2013 was 597 and 1139 km3 behind 2011 and 2012 respectively last month, the gap has widened back to 791 and 1597 km3. The red trend line is also clearly above that of 2010: 431 km3.
The minimum will occur somewhere this month, but there won't be much melt until then, so this is basically it for melting season 2013, and very educative it was. If it were a movie, I'd call it The Weather Strikes Back.
Here is Wipneus'
version with the calculated "expected" 2013 values (dotted
lines), based on the same date values of 1979-2011 and an exponential
A caveat from Wipneus: "Note that the statistical error bars are quite large."
Those error bars, large as they are, didn't manago to catch this year's anomalousness. It's clear that statistics has its limits, but this is pretty amazing. Which, of course, is exactly what the Arctic is. I take my hat off to anyone predicting this would happen at the start of the year. Except if he or she does so every year. :-)
For the first time since 2010 the anomaly from the linear downward trend hasn't dropped below the 2 standard deviation zone. Instead, it shot right back into the 1 standard deviation zone:
Average thickness (crudely calculated by dividing PIOMAS (PI) volume numbers with Cryosphere Today (CT) sea ice area numbers) is still lowest, though. Although a large part of that record amount of first-year ice at the start of the melting season has been preserved, it still is thin, of course:
Here's average thickness for August 31st in metres, with change from last month between brackets:
- 2005: 2.33 (-0.05)
- 2006: 2.19 (-0.22)
- 2007: 2.11 (-0.04)
- 2008: 2.43 (+0.00)
- 2009: 2.04 (-0.02)
- 2010: 1.43 (-0.14)
- 2011: 1.40 (-0.16)
- 2012: 1.39 (-0.13)
- 2013: 1.34 (-0.14)
If you want to have a look at the data yourself, you can download the spreadsheet I use and update from GoogleDrive.
On the thickness graph from the Polar Science Center 2013 is now slightly below last year, but well above 2010 and 2011:
Given yet another month of weather that causes the ice pack to lose less ice through melting, compaction and transport, it's no surprise that the volume numbers are high compared to the years following the big spring crash in 2010. We will now await the exact number for the minimum, and will then start to get ready for what the freezing season has in store for us. PIOMAS keeps proving that it is an excellent tool, one of the best we have for getting an idea of the state of the ice pack. We're lucky to have it.
My compliments and thanks go out to the team behind it at the Polar Science Center of the University of Washington.