Friday, April 13, 2012

3394.txt

date: Wed Apr 16 09:58:52 2008
from: Keith Briffa <k.briffaatXYZxyz.ac.uk>
subject: Re: CRU TS3.0
to: Gerard van der Schrier <schrieratXYZxyzi.nl>

Morning Gerard
the parameter I expect to be best represented in these data is the mean PDSI for summer, in
that the trees will grow well in spring and summer in response to warm conditions provided
there is sufficient soil water. They will not do well reconstruction temperature or
precipitation individually , or even in combination because of lag effects in the
association between rain and soil moisture , and over supply of rain will have no affect on
growth (or slight negative because of associated summer cold). As for the Gabbi idea we
would be better to discuss by phone. I will ring you
cheers
Keith
At 09:41 16/04/2008, you wrote:

Keith,

Ditto that you are happy to work on the 1000-year oak -based reconstruction - centred
on Northwest Europe. We will process the oak data and get back to you on this soon.

About these oak recons. - I am thinking of doing perhaps something similar to what Gaby
Hegerl did in her J. Clim paper (2007, detection of human influence on a new, validated
1500-yr temp. recon.) Do you think that's possible?
What exactly is the parameter you want to reconstruct with these oak data?
Cheers, gerard

cheers
Keith
At 10:24 15/04/2008, Gerard van der Schrier wrote:

Keith,
I've agreed with Ed that I do the PDSI calculations and do some additional quality
control tests. Harry will probably keep me updated when he finds more problems with the
data.
About the Int.J.Clim. paper: I've gone through the remarks you made and which you send
me. There are some issues the referees raised, like the infilling of data, which are
solved easily. We just have to put more emphasis on the remark we made that infilling is
only used for T, the places where P is infilled are flagged as absent and not used in
the analysis. I expect that other points are (nearly) as easy.
About the Dai paper and other plans with PDSI: the idea is to see if the
self-calibrating PDSI is changed dramatically if Penman-Monteith is used rather than
Thornthwaite, and i'd like to see a comparison using a complicated and the simple
waterbalance model as well. We've discussed this earlier and we don't expect any
problems here simply due to the calibrating which probably "adjusts" for any problems
with potential evapotranspiration. This should make one paper.
The next paper is a global dataset based on the updated CRU data - the rework of Dai's
paper. Now that we discuss this topic: I guess we may have problems in regions like the
Sahara or Siberia - any ideas yet? We could wait and see how the scPDSI behaves, but is
the PDSI a valid index for these regions anyway?
Cheers, Gerard

Gerard
do you wish me to chase this up ? Also can you update me on the Int.J.Clim paper status.
Are you considering a rework of the Dai global paper ? Cheers
Keith
At 08:38 14/04/2008, you wrote:

Hi Harry,
Sorry to bother you again about the CRU updated data.
Ed Cook and myself were wondering about the status of the CRU TS 3.0 data. Is it ready
or not yet? We are slightly confused about the status of this update.
Some time ago, I received an ftp address for this data and I downloaded the data (both
Temp - tx, tg, tn- and Precip). But later, I learned that CRU withdrew support for these
data - so I stopped working with these data.
Can you tell me where (which continents or which time periods) you suspect most in the
dataset I downloaded? (downloaded it at the end of September last year). Or would you
advise me not to use the data at all before there is a properly tested dataset?
Cheers, Gerard
--
----------------------------------------------------------
Gerard van der Schrier
Royal Netherlands Meteorological Institute (KNMI)
dept. KS/KA
PO Box 201
3730 AE De Bilt
The Netherlands
schrieratXYZxyzi.nl
+31-30-2206597
[1]www.knmi.nl/~schrier
----------------------------------------------------------

--
Professor Keith Briffa,
Climatic Research Unit
University of East Anglia
Norwich, NR4 7TJ, U.K.
Phone: +44-1603-593909
Fax: +44-1603-507784
[2]http://www.cru.uea.ac.uk/cru/people/briffa/

--
----------------------------------------------------------
Gerard van der Schrier
Royal Netherlands Meteorological Institute (KNMI)
dept. KS/KA
PO Box 201
3730 AE De Bilt
The Netherlands
schrieratXYZxyzi.nl
+31-30-2206597
[3]www.knmi.nl/~schrier
----------------------------------------------------------

--
Professor Keith Briffa,
Climatic Research Unit
University of East Anglia
Norwich, NR4 7TJ, U.K.
Phone: +44-1603-593909
Fax: +44-1603-507784
[4]http://www.cru.uea.ac.uk/cru/people/briffa/

--
----------------------------------------------------------
Gerard van der Schrier
Royal Netherlands Meteorological Institute (KNMI)
dept. KS/KA
PO Box 201
3730 AE De Bilt
The Netherlands
schrieratXYZxyzi.nl
+31-30-2206597
[5]www.knmi.nl/~schrier
----------------------------------------------------------

--
Professor Keith Briffa,
Climatic Research Unit
University of East Anglia
Norwich, NR4 7TJ, U.K.

Phone: +44-1603-593909
Fax: +44-1603-507784
[6]http://www.cru.uea.ac.uk/cru/people/briffa/

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