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.

Thursday, 8 January 2015

Where is the ice in the Bering Sea?

Like me, you've probably noticed the singular lack of ice in the Bering Sea, it is very unusual and the cause is northward air flow. That's as good an excuse as any for my first blog post of the 2015 sea ice year.


Tuesday, 6 January 2015

PIOMAS December 2014

The PIOMAS data for December 2014 is now out. So here is the usual summary. I start with the usual map plots of thickness, this time I've done an animated gif for September to December thickness.




Sunday, 4 January 2015

UK Rainfall 2014, a sneak peek.

I just, rather optimistically, checked UK rainfall data to see if it had been updated. It hasn't, but I was reminded that while the annual data is for January to December, the seasons run from December to November (using meteorological seasons). The main index I will continue to use will be the calendar year, January to December, but while I wait for PIOMAS data, here's a quick early look at UK rainfall for 2014.


Friday, 2 January 2015

Clarke's Third Law.

Happy New Year All!

Having been enjoying the long Christmas shutdown of the company I work for, I've been getting out and about, a few days ago I took a couple of busses, had a good walk, and got myself up to Winter Hill. It coalesced some thoughts I've had for years.



Saturday, 27 December 2014

Calculating insolation as a function of date and latitude.

In preparation for some work I will be doing I've been working on calculation of insolation as a function of time and latitude. In this post I will explain the method and compare results to a readily obtainable plot of insolation at various latitudes.

Note, all of the following calculations and the comparison with another source are for top of atmosphere and do not take into account absorption/scattering by the atmosphere, or reflection from clouds.