The PIOMAS graphs at the Polar Science Center of the Applied Physics Laboratory at the University of Washington have been updated. I'd like to start by showing Larry Hamilton's excellent graph that gives the best perspective:
It's already below last year's very low low. In other words, a new record minimum volume.
Here is the current volume as modeled by the folks from the APL/PSC:
And the volume anomaly:
Let me stress that these volume numbers aren't observed data, but are calculated using the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS, Zhang and Rothrock, 2003). The real numbers probably aren't off by much, and I base this on some snippets of information like the ice thickness measured at the North Pole by the Polarstern crew and buoy information, but we can't know for sure until the CryoSat-2 team starts churning out some well-calibrated numbers and ice thickness maps.
As always Wipneus was quick to update his graphs. Here is his graph showing all the yearly trend lines in the period 2002-2011:
We can clearly see 2011 has set a new record. These are the numbers of the last 6 yearly volume minimums, according to commenter Kevin O'Neill:
- 2006: 8.993
- 2007: 6.458
- 2008: 7.072
- 2009: 6.893
- 2010: 4.428
- 2011: 4.275 (and falling)
Here's Wipneus' graph that shows the monthly average with exponential trend:
Mind you, no one here is expecting the trend line to continue falling like that. It's just that the current trajectory is following the exponential downward trend. By the time volume really gets low some negative feedback might kick in and slow things down.
Wipneus has one last graph that shows a little bit more clearly that the current number actually is right on the projected exponential downward trend (although the minimum probably hasn't been reached yet):