Wednesday, March 31, 2010

Comparison of GHCN results

I promised some comparison plots from the code reported in the last post, but Zeke has made the task much easier. He posted a spreadsheet with all the data nicely arranged, and I added my own data - you can find the spreadsheet "Temp Comps_NS.xls" in the repository.

Below are some of the plots and discussion.

A summary of this series of posts is here.

GHCN processing algorithm

As Zeke says, it seems to be a custom now for bloggers to post codes to grid GHCN data and calculate trends. Here's my offering. It's influenced by Jeff Id's program, and particularly by Romanm's Least Squares. In fact, it's an extension of Roman's offset method to the whole global set. It's fairly different to the conventional approach. It doesn't actually do gridding, or (per Roman) calculate anomalies. It's probably the shortest of the codes, and runs quite fast.

A summary of this series of posts is here.

Thursday, March 11, 2010

On Polynomial Cointegration and the death of AGW

Well, I never thought I'd write a post with such a title. And I must confess that until about two weeks ago, these terms were very foreign to me. But recently, a paper by the econometricians Beenstock and Reingewertz has been circulating among sceptic blogs. It seems unpublished, but with the file called "Nature_Paper091209.pdf" there has been some jumping to conclusions. There was a brief discussion at WUWT, and more recently, David Stockwell has run a series on the topic.
Update.  Bart has commented has commented and linked an interesting discussion on his blog. Tamino has taken this up with a very thorough discussion (with sequels). The first properly sceptical discussion of the Beenstock paper was by Eli Rabett

Further update. VS has noted that the much more significant thread on Bart's blog (now much discussed in itself) is here.

Ringing phrases like:
"Therefore, greenhouse gas forcings, global temperature and solar irradiance are not polynomially cointegrated, and AGW is refuted."
ensure that those who like that sort of thing will keep it going for a while, so I thought I should try to figure it out. I'm still not an expert, but I hope what I did figure out might help.

Saturday, March 6, 2010

A blatant fiddle in the D'Aleo/Watts SPPI report.

The D'Aleo/Watts report has come under justified criticism for it's silly claims about marching thermometers etc, amplified into claims about malfeasance by various scientific groups.

But there's one little thing that particularly bugs me, because I have pointed it out more than once, but it makes no difference. They say  

"See the huge dropout of data in Africa, Canada and Siberia in the two maps from NASA GISS with 250 km smoothing from 1978 to 2008"

and show these pictures: