A good start

One of the commenters of this blog, Chris R, informed us in the comment section of SIE update 11 that he has started a blog and kicked it off with a couple of posts on Arctic sea ice (always a good start).

Most of us know this graph (from NSIDC monthly summaries, which I also used in this post on Ice thickness models) that Chris R uses at the start of The loss of multi-year sea ice, Part 1:

What is interesting is how Chris R compares Maslanik's graph with another graph from Nghiem et al's Rapid reduction of Arctic perennial sea ice (2007):

And follows it with the following question:

Both are startlingly different, yet apparently cover the same thing - the fate of the MY sea ice. So why is there a difference between Nghiem 2007 and James Maslanik's treatments of the loss of perennial sea-ice? And does this difference tell us anything of use?

There are various differences between the aproaches of Nghiem and Maslanik, also differences in the areas covered. However in my opinion the major difference is in the treatment of mixed ice.

I can recommend reading this blog post as well as the other ones he has produced so far:

The loss of multi-year se ice, Part 2

In flux

Comments

[Al Rodger]

The two graphs do give roughly similar numbers if you work them into common units (sq km *10^6) although Maslanik does plot a significantly lower decline.
Year 2007 2002 1992 1892
Maslanik 2.8 3.7 4.1 4.5
Nghiem 2.6 4.2 4.5 5.0

[Chris Reynolds]

Thanks Neven,

I didn't expect this much attention. ;)

If anyone wants to discuss over here I'll make sure I'm around. Being on UK time though I'll have to leave it till tomorrow night.

In my 'In Flux' post I made an embarrasing error due to late night posting. Ice thickness feedback is far more due to open water at the end of the season and the release of heat due to the latent heat of fusion than due to thinner sea ice. Serreze et al in "The emergence of surface-based Arctic amplification." imply that energy loss due to thinner ice is a small factor.
"...This indicates that most of the increase in mean annual (and autumn) SAT over the Arctic associated with ice loss is due to the ice extent change and not changes in thickness."