Thursday, May 24, 2012


date: Wed, 4 Dec 1996 11:57:11 +0100 (MET)
from: (Gabriele Hegerl)
subject: Re: The graphs sent
to: (Phil Jones)

Dear Phil,

Sorry - my head seems slow due to cold (its always slow but still
slower today...): What you are saying is that it is much better to
use the "new" IPCC data? What is K&J?
Should I redo the signal-subtraction exercise (would be VERY easy) with the new data?

What would not be that easy would be redoing my paper (rep 207) with the Jones
+ parker data (different data coverage => different EOFs for truncation
=> all studies inclusive sensitivity anew.. - I can do sloppy checks in the
"old" data space and
saw that it does change the results, but not dramatically - however, I have
to admit they look somewhat worse. EG the strong values for the det var
at present is somewhat reduced relative to the fourties. This may be due
to the cooling south of greenland). I really don't know what to do
- on the one hand, its such a lot of work to redo everything and I don't
have enough time to really do it - on the
other hand I feel somewhat uneasy about the present results...

Do the signal subtraction results resemble yours? How large is your
residual signal?

Looking forward to the AMS


> Gabi,
> I've had a look at the results you sent me last week. We're doing
> some PC analysis on the new data and have noticed some
> differences regrading the PCs and earlier work - particularly with
> regard the ENSO extraction that was in the recent JGR paper (Kelly
> and Jones 1996).
> What we see is that there is more definition in the newer data -
> ie more detail and more significant PCs required to explain a certain
> amount of the variance. The PC that showed strongly in K&J over the
> Antarctic drops down the order but is still there but with much
> lower variance.
> In short the interpolation techniques to get J&B 92 have probably
> oversmoothed some features. This is something we are going to have to live
> with as I can no longer get the J&B analysis updated.
> I hope the trip goes well to the US. In the meantime I hope to
> have synthesised the ice core series by the time of the AMS meeting
> in Feb.
> Cheers
> Phil
> Dr Phil Jones
> Climatic Research Unit Telephone +44 (0) 1603 592090
> School of Environmental Sciences Fax +44 (0) 1603 507784
> Norwich Email
> NR4 7TJ
> UK
> ----------------------------------------------------------------------------

Gabriele C. Hegerl Phone: +49/40/41173-309
Max-Planck-Institut f. Meteorologie Fax: " -298
Bundesstr. 55 email:
D-20146 Hamburg

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