Friday, May 4, 2012


date: Tue Oct 30 10:39:40 2007
from: Tim Osborn <>
subject: Re: Questions about CRU CL 1.0
to: Ian Harris <>

Harry -- I'm catching up on old emails including the one below from a month ago... the
answer is "no" I don't know. Helpful aren't I?! Tim
At 09:17 26/09/2007, you wrote:

Hi Phil, Tim,
Do either of you know the answers to these questions?
On 26 Sep 2007, at 8:48, Sheppard Sylv Miss ((SCI)) wrote:

-----Original Message-----
From: Jongschaap, Raymond [[1]]
Sent: Wednesday, September 26, 2007 8:16 AM
To: Sheppard Sylv Miss (SCI)
Cc: Jongschaap, Raymond; Conijn, Sjaak
Subject: Questions about CRU CL 1.0
Dear Dr Mitchel, or CRU colleague,
I would like to know if you could help me out with some questions
concerning the CRU CL 1.0 data-set, that is available on your website.
In the above database radiation (rad, W m-2) is provided, although
in the paper of New et al. (1999), this variable is not mentioned.
My questions are:
1) Where can I learn how this variable was derived, and
2) As Rad is given as W m-2 (or J m-2 s-1); is this an average
value for a day in a given month? Does this apply for 24 hours, or
for the daylength period only? As you may understand, I would like
to obtain the daily or monthly value of rad, and don't know which
mulitplier I should use.
My last question is about vapour pressure (vap, hPa) and wind speed
(wnd, m s-1)
3) Are these mean values for a day (24 h) in a given month or do
they apply for the daylength period of that day only?
I hope you can help me out ASAP with some (partial) answers,
Best personal regards,
Dr. ir. R.E.E. Jongschaap
Sustainable farming systems, Bioenergy, Simulation modeling and
Remote Sensing
Wageningen University and Research centre
Plant Sciences Group
Plant Research International
Dept. Agrosystems Innovations
T +31 (0)317 475953 / [new: 480570]
F +31 (0)317 423110
W [2]
Postal address:
P.O. Box 16
NL-6700AA Wageningen
the Netherlands
Visiting address:
Bornsesteeg 65
Building 122, room 0.24
NL-6708PD Wageningen
the Netherlands
Jatropha curcas evaluation, breeding and propagation programme
W [3]

Ian "Harry" Harris
Climatic Research Unit
School of Environmental Sciences
University of East Anglia
Norwich NR4 7TJ
United Kingdom

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