On the problems attendant in denying a real and ongoing physical process.

Am I the only one who's not seen this version of Downfall?

 



 

GISS LOTI and NCEP/NCAR Reanalysis.

In my last blog post (link) I outlined a recent paper that reveals some detail about the structure and cause of Arctic warming, in it I touched upon some concerns with reanalysis. It is notable that NCEP/NCAR doesn't tend to be used in studies of the Arctic, newer reanalysis products such as JRA-25 and ERA seem to be preferred by most researchers. However the reasons for this seem to be in details in literature I've not yet read, I'm not aware of any one paper throwing NCEP/NCAR temperature or pressure outputs into doubt in the Arctic. It would seem that whatever issues there are have not been enough to persuade the PIOMAS team not to use NCEP/NCAR.

But there is one issue I'm aware of; a growing mismatch between NCEP/NCAR reanalysis and GISS Land/Ocean Temperature Index (GISS LOTI).

The Causes of Arctic Amplification.

Arctic Amplification is the term used for the enhanced warming of the Arctic when compared to warming rates for the rest of the globe. While the changes in the Arctic are driven by human activities, as discussed previously, human activities have proven little more than a 'prompting' for a region whose dynamics are driven by powerful feedbacks.

The Arctic is warming, but the pattern of warming over the year, and between surface and aloft is complex, what is causing this warming? In 2012 Screen et al published "Local and remote forcing of observed Arctic warming", PDF in which they used a series of reanalysis data sets and the results of experiments in two climate models to examine the causes of Arctic Amplification.

Mid April Miscellanea.

The mid month round up of odd bits that interest me and don't fit elsewhere is here. You won't find the 'A' word anywhere in this one.

NOSEDIVE!

 

PIOMAS: 2013 so far.

Dr Schweiger has been good enough to let me know that thickness fields from PIOMAS gridded data are now available for 2013 up to March. Previously it seems to have been released in January for the previous year. Let's hope they get the chance to update periodically in what I suspect will be an exciting year on the ice.

Long Tail or Fast Crash?

As explained in my last post I've been puzzled by the potential implications of autumn/winter ice growth in response to summer area minimums to cause a cessation* to sea ice volume loss. EDIT - not really a cessation, just a reduction in the trend of loss.

As a result I've been playing around with some toy models based on past behaviour, on the principle that whatever factors are to play a role in what is coming, these factors are already at work. The issue here is not the closeness to observation or the PIOMAS model, but the qualitative form of the output and whether that helps say what will happen in the future.