Sunday, June 10, 2012

5043.txt

cc: Edward Cook <drdendroatXYZxyzo.columbia.edu>, p.jones@uea.ac.uk, "Gerard van der Schrier" <schrieratXYZxyzi.nl>
date: Mon, 21 Apr 2008 06:13:07 +0700
from: Edward Cook <drdendroatXYZxyzo.columbia.edu>
subject: Re: CRU TS3.0
to: t.osbornatXYZxyz.ac.uk

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Hi Tim,

I just did a Google search on "CRU TS 3.0" to see if I could find any
reference to it for a progress report I am writing and hit upon your
site "TimOsborn's ClimGen". I kind of figured that it wasn't supposed
to be found that way given the very targeted audience that it
appeared to be for. Your cautionary tail is also appreciated. It
sounds like TS 3.0 has been a real challenge to get right.

Cheers,

Ed
==================================
Dr. Edward R. Cook
Doherty Senior Scholar and
Director, Tree-Ring Laboratory
Lamont-Doherty Earth Observatory
Palisades, New York 10964 USA
Email: drdendroatXYZxyzo.columbia.edu
Phone: 845-365-8618
Fax: 845-365-8152
==================================

On Apr 21, 2008, at 4:14 AM, Tim Osborn wrote:

> Hi Gerard and Ed,
>
> I didn't think that I'd linked my climgen data page from anywhere else
> (yet) because it isn't ready for public release (yet), though I have
> forwarded the URL to a few "private" users -- maybe they have added
> it as
> a link to their websites? May I ask where you stumbled across it?
>
> There have been many problems with CRU TS 3.0 data files so far. I
> probably wouldn't use anything from Sep 2007 -- though perhaps mean
> temperature (tmp) is ok; certainly min and max temperature (tmn and
> tmx)
> and precipitation (pre) are rubbish and aren't salvageable by
> avoiding a
> few regions! If you got vapour pressure and/or wetday counts, then
> those
> too were almost completely wrong.
>
> However, I'm much more confident about the accuracy of the files on my
> climgen website, which Harry has re-calculated over recent weeks. At
> least for data since 1950. There's probably some problems during
> 1901-1950, though probably fewer that in the CRU TS 2.1 version
> (though
> some problems are new!). No doubt there are some problems post
> 1950 too,
> but again there were probably more in CRU TS 2.1. Still waiting for
> vapour pressure and wetdays, and cloud cover updates are some
> months away.
>
> The question is, are they ready for use? Nobody has really used
> them in
> anger yet. I'm distributing them to the QUEST-GSI project, who will
> probably be the first users -- they may find problems that we may
> correct.
>
> If you're willing to use them with the expectation that there may
> be some
> updates to correct certain problems (more so before 1950 I'd
> guess), then
> I'm happy for this. Harry sounds as if he isn't -- or at least
> that he
> wasn't so happy for them to be distributed back in Sep 2007. I've
> cc'd
> Phil to see what he thinks -- also Phil may want to say how you
> might cite
> the data set (e.g. provisional paper authors/title?).
>
> If you do use the data, then the ascii/text files on my climgen
> website
> are in a fairly self-explanatory format (time series for each land
> grid
> box), though Harry has also produced netCDF files containing grids of
> monthly data.
>
> Cheers
>
> Tim
>
> Regarding data versions,
> On Sun, April 20, 2008 10:44 am, Edward Cook wrote:
>> Hi Gerard,
>>
>> Perhaps you already know it, but apparently the precip problem over
>> Bangladesh has been corrected now (Harry indicated that was in
>> progress) as indicated by a website description of Tim Osborn
>> (http://
>> www.cru.uea.ac.uk/~timo/climgen/data/questgsi/). He even provides an
>> ftp link for the TS 3.0 data files (http://www.cru.uea.ac.uk/~timo/
>> climgen/data/questgsi/globobs/), perhaps not thinking that I would
>> stumble across it. Anyway, if not already too late, perhaps you will
>> want to use the newest version of the TS 3.0 precip data to generate
>> the global scPDSI data.
>>
>> Cheers,
>>
>> Ed
>> ==================================
>> Dr. Edward R. Cook
>> Doherty Senior Scholar and
>> Director, Tree-Ring Laboratory
>> Lamont-Doherty Earth Observatory
>> Palisades, New York 10964 USA
>> Email: drdendroatXYZxyzo.columbia.edu
>> Phone: 845-365-8618
>> Fax: 845-365-8152
>> ==================================
>>
>> On Apr 15, 2008, at 1:18 PM, Gerard van der Schrier wrote:
>>
>>> Hi Ed,
>>>
>>> Given Harry's reply, shall I just use the data I have (version of
>>> September 2007), and run some quality control checks?
>>>
>>> Cheers, Gerard
>>>
>>>
>>>
>>> Hi Gerard,
>>>
>>> On 14 Apr 2008, at 8:38, Gerard van der Schrier 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.
>>>
>>> Sorry about that. If it was up to me, there would be no confusion
>>> because nobody would have seen it at all.. but in real life there
>>> are shifting priorities..
>>>
>>>> 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?
>>>
>>> I *think* temperature is OK. Precip has a few glitches, (which
>>> I've been investigating over the past two weeks), the major one
>>> is Bangladesh in the 1990s. Here, updates were added to the
>>> database a year or two back but were 10x too low.. I've now found
>>> and corrected that. Precip *currently* being regernerated (as I
>>> type!).
>>>
>>> So - use Temp, and Precip but not Bangladesh. Or anywhere else
>>> that looks odd when you examine it ;-)
>>>
>>> Cheers
>>>
>>> Harry
>>>
>>>
>>>>
>>>> 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
>>>> www.knmi.nl/~schrier
>>>> ----------------------------------------------------------
>>>>
>>>
>>> Ian "Harry" Harris
>>> Climatic Research Unit
>>> School of Environmental Sciences
>>> University of East Anglia
>>> Norwich NR4 7TJ
>>> United Kingdom
>>>
>>>
>>>
>>>
>>> --
>>> ----------------------------------------------------------
>>> 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
>>> www.knmi.nl/~schrier
>>> ----------------------------------------------------------
>>
>>
>
>
>

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