Monday, 2 March 2015

Evolution in day to day sea ice extent change.

In the comments to my previous post commenter Pete asked about the changes in the seasonal cycle with regards the date of maximum and minimum. In looking at this apparently simple question it actually has all ended up being rather complex, which may say more about me than the question. So sorry Pete, I still haven't really got a post looking at your question, although I do close by touching upon the issue.

However in playing around with the data, trying to settle on a method that will produce a sound answer, I have ended up being diverted by an idea I thought worth pursuing.

Thursday, 19 February 2015

FDDs and Sea Ice Loss

At the end of my last blog post of the Slow Transition series I tagged on a comment and graph about Freezing Degree Days and CO2, I said I would need to think about it. Having been rather distracted by other matters it's taken some time for me to look at it. However I have now done so and in short I don't think CO2 is directly driving winter warming.

Friday, 6 February 2015

January Status: PIOMAS

January's PIOMAS data was released yesterday, it shows that the volume gain over 2012 has decreased massively. But does this really mean the increased volume of 2013/14 is going to go away within one winter?

Monday, 2 February 2015

January Status: Extent

In this first monthly status blog post of 2015 I'll be using a technique used last year in this post. But I will explain, so no need to go reading that post before you read this one. To be frank there isn't a great deal of demand from the data for anomalies, but it's as well for me to start using the technique as I will throughout this year.

A separate PIOMAS post will follow when that data is out.

Thursday, 29 January 2015

The Slow Transition: The Mono-modal Spike.

In my previous post I looked at the implications of winter thickening for the question of whether Arctic Sea Ice faces a rapid crash or a slow transition to a seasonally sea ice free state. There is another aspect of the PIOMAS data which throws light on this, and which shows something I have commented on in recent winter commentaries.

Saturday, 17 January 2015

The Slow Transition: The Thickness Growth Feedback

PIOMAS data is often used in statistical extrapolation to support claims of an imminent crash of summer sea ice. However Zhang 2010 ("Arctic sea ice response to atmospheric forcings with varying levels of anthropogenic warming and climate variability" PDF) uses the very same model in a future projection and finds no such crash. What is going on? Which approach and conclusions are to be trusted?

Monday, 12 January 2015

The simplest model of sea ice growth

This post is acting as an appendix for a blog post I'm writing at the moment. In this post I describe a very simple physical model of sea ice growth and the conversion to a Freezing Degree Days format.