date: Mon, 14 Sep 2009 10:40:30 +1000
from: "Don McNeil" <dmcneil@efs.mq.edu.au>
subject: seasonal adjustment?
to: <p.jones@uea.ac.uk>

Dear Phil:

I note that the HadCRUT3v temperature data have been seasonally adjusted because the monthly effect is small, and I wonder if you could tell me the method you used to do it. I've read your 2006 paper (by downloading the PDF file from your site) but cannot see where you say precisely how the data were adjusted (apart from subtraction the 1961-2000 averages for each grid location from all the values for each grid). Did you do the same thing for the monthly averages, that is, by calculating and subtracting monthly averages for each grid location for data from the period 1961-2000?

I presume the method is explained more fully in other papers you have written, but I can't easily get these complete papers from the Internet here in Thailand. Thai universities usually can't afford to pay for the subscriptions.

Kind regards....Don