Arctic Sea Ice

PIOMAS May 2012

Another month has passed and so here is the updated Arctic sea ice volume graph as calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center:

This year's trend line dipped below last year's only to go up again in the first two weeks of April, probably reflecting the late ice growth we saw here and there on the fringes of the ice pack, that also had trend lines on extent and area graphs flirting with the long-term average for a while. Very similar to 2010, but with thinner ice according to PIOMAS.

Here is Wipneus' graph for which he calculated the "expected" 2012 values, based on the same date values of 1979-2011 and an exponential trend. A caveat from Wipneus: "Note that the (not indicated) statistical error bars are quite large."Because there haven't been any updated CT SIA numbers I cannot update the average thickness map (PICT) I first posted last month. I'll update this post as soon as the sea ice area data comes online.

For the time being I'm posting the PIOMAS anomaly graph:

PIOMAS April 2012

Another month has passed and so here is the updated Arctic sea ice volume graph as calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center:

Still on a par with last year.

Wipneus produces many excellent PIOMAS graphs. I'll start with his latest creation, the graph for which he calculated the "expected" 2012 values, based on the same date values of 1979-2011 and an exponential trend. A caveat from Wipneus: "Note that the (not indicated) statistical error bars are quite large."

As a bonus I have finally come round to making a new graph, one that very crudely shows average ice thickness across the Arctic, by simply dividing the PIOMAS volume numbers (km3) by the Cryosphere Today area numbers (km2), and multiplying them by 1000 to get the average thickness in meters:

PIOMAS March 2012

The Arctic sea ice volume graph as calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center has been updated:

Slightly lower than last year...

Wipneus has produced a new graph for which he calculated the "expected" 2012 values, based on the same date values of 1979-2011 and an exponential trend. A caveat from Wipneus: "Note that the (not indicated) statistical error bars are quite large."To top it off, here's the PSC graph with the anomaly from the downward trend:

February 2012 Open Thread

There's a poll in the right hand bar running until February 8th for predicting the Cryosphere Today maximum sea ice area number. Don't be afraid to share your prediction in the comments of this thread: 2012 Maximum Area Pool

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We are entering the final phase of the freezing season. After that there will be a short lull, with sunlight and warmth trying to grab the Arctic back from Winter's clutch. Then the melting season will start all over again.

Image retrieved from this blog post on ringed seals

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Edit February 4th: the scientists at the University of Washington's Polar Science Center have updated the PIOMAS volume graph:

PIOMAS September 2011 (volume record lower still)

The PIOMAS graphs at the Polar Science Center of the Applied Physics Laboratory at the University of Washington have been updated. It reached an all-time low of 4.4 thousand km3 last month, but went down some more as we can see on Larry Hamilton's stack graph (Larry also wrote a great blog post discussing these numbers):

So the new record minimum volume is 4.0 thousand cubic kilometers.

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.

Commenter graphs

As always Wipneus was faster than the speed of light (or neutrinos if you prefer) and updated his graphs. Here is his graph showing all the yearly trend lines in the period 2002-2011:

September 2011 sea ice volume, looking back and ahead

Last spring I proposed Gompertz curves as simple models for thinking about past and future trends in Arctic sea ice extent, area and volume. Extent and area predictions made using these models in April came close to the observed September means:

NSIDC extent — predicted 4.4, observed 4.6

UB extent — predicted 4.6, observed 4.6

NSIDC area — predicted 3.1, observed 3.2

But the April volume prediction, based on what seemed at the time to be a pessimistic model, turns out to have been too high:

PIOMAS volume — predicted 5.2, observed 4.2

As estimated by researchers at the Polar Science Center of the University of Washington, using the PIOMAS model (website, data), the mean volume for September 2011 was only 4.2 thousand km³. Figure 8 shows this result together with a new Gompertz curve, which points toward a September 2012 mean of 4.0 thousand km³. Whereas the earlier model showed volume reaching very low levels (below 2 thousand km³) around 2016, this new version crosses that line one year sooner.

 
Figure 8

Final score: 2011 vs 2007

Now that I've called the minimum, it's time to have a look at the differences between the two years with the lowest minimums in all data sets. This post will be a potpourri of different factors.

If we look at the six most important data sets - which IMHO are IJIS extent, NSIDC extent, Cryosphere Today area, Uni Bremen extent, DMI extent and PIOMAS volume - we see that this year a new record has been reached in three of them:

In the remaining three (NSIDC, IJIS and DMI extent) 2007 still holds the record low, but 2011 brushes past very closely and is firmly in second place:

If we compare the sea ice concentration maps from the University of Bremen we can see how close 2007 and 2011 match, despite differences in final shape:

PIOMAS August 2011 (new volume record)

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.

Commenter graphs

As always Wipneus was quick to update his graphs. Here is his graph showing all the yearly trend lines in the period 2002-2011:

PIOMAS July 2011

The PIOMAS graphs at the Polar Science Center of the Applied Physics Laboratory at the University of Washington have been updated. Here is the current modeled volume:

And the volume anomaly:

Commenter graphs

As always Wipneus was quick to update his graphs. Here is his graph showing all the trends in the period 2002-2011:

PIOMAS June 2011

The PIOMAS graphs at the Polar Science Center of the Applied Physics Laboratory at the University of Washington have been updated. Here is the current modeled volume:

And the volume anomaly:

Another steep drop. As per the PSC/APL website: