Friday, May 25, 2012

4692.txt

cc: Phil Jones <p.jonesatXYZxyz.ac.uk>
date: Mon, 14 May 2007 17:25:44 +0100
from: Ian Harris <i.harrisatXYZxyz.ac.uk>
subject: Re: cru ts2.1
to: Sandy.HarrisonatXYZxyzstol.ac.uk

<x-flowed>
Hi Sandy,

Please see:

New, M., M. Hulme and P. Jones (1999). "Representing twentieth-
century space-time climate variability. Part I: Development of a
1961-90 mean monthly terrestrial climatology." Journal of Climate 12:
829-856.

It's available as a PDF here:

http://www.ouce.ox.ac.uk/~mnew/research/publications/
new_et_al_20th_climate_part1_JoC.pdf

On page 832 they discuss the definition of a 'wet day' - the decision
is to go with 0.1 mm.

However, do bear in mind that the CRU TS 2.1 'rd0' variable is, in
part, derived from monthly precipitation - where the relationship to
daily rain day definition is obviously more convoluted!

Our local precipitation expert tells me that, in effect, 'any'
precipitation may be used to define a rain day. I think this is
taking advantage of rain being measured to one decimal place!

Hope that helps,

Harry

On 14 May 2007, at 7:57, Phil Jones wrote:

>
>> Date: Sun, 13 May 2007 18:42:37 +0100
>> From: "SP Harrison, Geographical Sciences"
>> <Sandy.HarrisonatXYZxyzstol.ac.uk>
>> To: p.jonesatXYZxyz.ac.uk
>> Subject: cru ts2.1
>> Originator-Info: login-token=Mulberry:01SIcReq/
>> uhOp7yIrkdq7tPuOA6YediLr9P9yF8Yqedqu1huU=;
>> token_authority=postmaster@bristol.ac.uk
>> X-Mailer: Mulberry/3.1.5 (Win32)
>> X-Spam-Score: -21.4
>> X-Spam-Level: ---------------------
>> X-UEA-Spam-Score: 0.0
>> X-UEA-Spam-Level: /
>> X-UEA-Spam-Flag: NO
>>
>> Hi Phil,
>>
>> No, I am not bugging you about updates -- although it would be
>> good to know where you are with this.
>>
>> Actually, I would like to know what threshold (if any) was applied
>> in the definition of a wet day in the CRU TS2.1 data set. I have
>> not been able to find this anywhere in the documentation. The
>> reason I'm interested is that we are trying to derive wet days
>> from GCM output, and I am wondering whether we can use/should use
>> the sort of threshold that might be used with real climate data ..
>> or whether we should deal with the drizzle problem by setting the
>> threshold higher. So the first step is ... what is the threshold
>> used in the CRU data sets.
>>
>> Any thoughts on this would be appreciated ...
>>
>> Cheers,
>> Sandy
>>
>> ----------------------
>> Professor Sandy P. Harrison
>> University of Bristol
>> School of Geographical Sciences
>> University Road
>> Bristol BS8 1SS
>> UK
>> Sandy.HarrisonatXYZxyzstol.ac.uk
>>
>> PA - Katie Pellicci
>> Katie.PellicciatXYZxyzstol.ac.uk
>
> Prof. Phil Jones
> Climatic Research Unit Telephone +44 (0) 1603 592090
> School of Environmental Sciences Fax +44 (0) 1603 507784
> University of East Anglia
> Norwich Email p.jonesatXYZxyz.ac.uk
> NR4 7TJ
> UK
> ----------------------------------------------------------------------
> ------

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


</x-flowed>

No comments:

Post a Comment