cc: "Collins, Matthew" <matthew.collins@metoffice.gov.uk>, Keith Briffa <k.briffa@uea.ac.uk>
date: Wed, 1 Feb 2006 11:16:23 +0000
from: Thomas Kleinen <t.kleinen@uea.ac.uk>
subject: Re: HadCM3 control run results
to: Tim Osborn <t.osborn@uea.ac.uk>

Hi Tim and Matt.

> (1) On the comparison with observations for near-surface temperature,
> you get large "errors" over winter sea ice regions.  It might be
> worth checking what the HadCRUT climatology represents over the
> oceans - is it marine air temperature or SST.  If the latter, then it
> won't fall below -2 deg C and this would explain the big "errors"
> when comparing with HadCM3 1.5m air temperature.  Even if this is not
> the case, and HadCRUT climatology purports to be marine air
> temperature, then I wouldn't believe the values over sea ice areas
> anyway!  They'll have been extrapolated from a very few data points
> or only from Arctic buoys that didn't cover the whole 1961-90 period.

Supposedly it is air temperature, according to the documentation I could find 
(our data webpage isn't documented all THAT well), but I am not too worried 
about that anyway. So far I am mainly concerned with having a model 
configuration that gives output similar to the MetOffice's one. And that it 
seems to do.

> (2) For the UEA control minus Hadley control results, does the
> difference pattern stay constant between, say, the early part of the
> UEA run and the later part.  This would imply a systematic
> problem.  So how does UEA(30-59)-HAD(3160-3189) for DJF SLP compare
> with the UEA(60-89)-HAD(3160-3189) pattern that you showed?  I guess
> the statistical testing you have done implies that it is sampling
> variability rather than systematic, but it'd still be nice to see how
> the two periods' results compared for DJF SLP.

No, those differences are random. The pattern doesn't stay contant, from what 
I've seen.
We'll have more data next week, so I can do some more checks, but my main 
concern right now is whether our ocean is ok. More on that next week.

Cheers,
Thomas
