Tuesday, December 20, 2011

Wacky numbers and perturbing to the climate of Venus and negative sunshine, oh my: A revealing glimpse into the climate model sausage factory

ClimateGate email 693

Presumably the wacky numbers are the result of fitting pdfs to (small) samples of changes:

...1. Arbitrarily capping the changes is, as we discussed previously, not desirable, for
several reasons, including introducitn of bias if you simply truncate.
But, we have to do this in some form in order to stop the WG falling over!
3. A little galling to spend time fixing the WG up to reproduce control to good level, and
then perturb to the climate of Venus, and as various people having criticised CP.net for
retaining wacky numbers (me included), difficult to see how we can justify this sort of
thing now!
[Phil Jones] The other values that cause the WG to crash are some of the DTRs and the July
Sunshine. It is the reductions that cause the problem. We can put a trap in for
these but they make no sense. There are two examples of DTR reducing by >7 deg C
in November. The problem here is that this is larger than the actual DTR for November..
The drops in sunshine in July (on two occasions) are larger than the average sunshine,
which means the WG ends up with negative sunshine! ... As I understand it
the users will be able to get access to these numbers - which cause us lots of

Hat tip: AJ

No comments: