2013 PIOMAS Volume Minimum Projection

Over at the Sea Ice Forum there's a long running discussion about predicting sea ice volume, link. This has finally prompted me to pull my finger out and do something I've been pondering for a while. Answering the question: What if I apply previous year's thinning profiles to the most recent thickness data from PIOMAS? What I find is no new record, with 2013 beating 2011, but not beating 2012.

Autumn Sea Ice Area

In my previous post I showed the post 2007 changes to the seasonal cycle of the Cryosphere Today sea ice area index (CT Area) in the context of previous decades. A notable part of this is the rapid climb of anomalies in the autumn after the lowest record area minima.

CT Area Anomalies

Cryosphere Today produce a dataset of sea ice area, which I shorthand as CT Area. Calculating the daily average over a long period gives an average sea ice area for each day (baseline average), subtracting these daily anomalies from the actual sea ice area data for each day of a given gives the daily anomaly. These daily anomalies are the differences from the average seasonal cycle. I use the period 1980 to 1999 as the baseline average period.

In this post I present graphs of the daily anomaly series from 1980 to 2012. This is a place holder for reference from future posts.

Click on any of the images to bring up full screen, with a selection menu at the bottom of the screen (this applies to all posts on this blog).

April 2013 Status

PIOMAS daily series data is now available for April, so it's time to include the Cryosphere Today Area and look at the status of the pack. Later in the year I may bring in discussion of what's happening in regions, but I see nothing at present that's important for the progress of the season in the concentration plots or IR satellite images.

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.