Saturday, May 7, 2016

Sea Ice Forecast

It's interesting to note that NOAA's CFSv2 long-range forecast model is again predicting a very substantial increase in sea ice this summer in parts of the Arctic Ocean.  The map below shows a large positive anomaly in sea ice concentration in August stretching from the eastern Kara Sea all the way east to the Beaufort Sea.  If this was the first time we'd seen this, it would be worth paying attention, but the model produced a similar forecast in 2014, and it proved to be completely wrong (see here and here).

The CFSv2 "nowcast" for May shows a large ice deficit in the Bering Sea (see below), which is correct, so it seems the model is not developing the summer ice excess from erroneous initial conditions; the anomaly is being generated from the internal physics of the sea ice component of the CFSv2 system.  Assuming the forecast proves incorrect again, I'd say this aspect of the model needs some attention.

According to the forecast, the sea ice anomaly persists into the autumn and helps generate a really remarkable cold anomaly on this side of the Arctic - see the temperature forecast map for October, below.  It seems very unlikely indeed that anything remotely like this will happen; simply put, I think the model is "out to lunch".  But time will tell.  (As an aside, note the La NiƱa cold anomaly in the equatorial Pacific; this is reasonably likely to be correct.)

Here are the latest charts of observed Arctic sea ice from NSIDC; total ice extent is running close to record low levels for the time of year, and there seems to be a fair chance of a new record melt-out later this year.  Unless of course the CFSv2 is onto something.

1 comment:

  1. Current Sea ice related topic: