Wednesday, April 25, 2012

3503.txt

cc: Dennis Wheeler <dennis.wheeleratXYZxyzderland.ac.uk>, "Frits B. Koek" <koek@knmi.nl>, konnen@planet.nl, Ricardo Garcia Herrera <rgarciahatXYZxyz.ucm.es>
date: Tue, 16 Jan 2007 14:13:39 +0100
from: David Gallego <dgalpuyatXYZxyz.es>
subject: Re: New historical series and some post-CLIWOC results
to: Phil Jones <p.jonesatXYZxyz.ac.uk>

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Phil, Dennis, Gunther and everyone,

Thank you for your inputs!

Phil, I just received your email with the Manolas's paper. Thanks! Up to
now we could not compare our data with that of the Barcelona's group (I
don't have the IMPROVE CD). We already contacted Mariano Barriendos and
now we are waiting for his series. Hopefully within the next few weeks
we will be able to carry out some analysis. Our idea is to include the
comparison in the paper.

Regarding the similar results for the Alpine region and Northern Italy,
is there any reference with these results already? I think it will be
extremely interesting to explicitly extend the area characterized for
warmer-than-average summers in the 1830s-1840s to southern Europe.
Unfortunately, we can't look at a continuous series for Cadiz. Our
reconstructions ends at 1852 and the present day data provided by the
national meteorology institute are rather discontinuous before 1960...

Dennis, it's not in our paper, but we did some comparison with the
Gibraltar pressure series and at least, the monthly averages seemed to
agree quite well. We did not perform daily comparisons.

All, regarding to the CLIWOC-relation, we are a bit concerned about the
"tone" of our discussion. We are not sure if it can be interpreted as if
the entire CLIWOC database is overestimated by a factor of 2 and in
fact, this result is strictly applicable to the Cadiz data (we�ll
include a paragraph to make this clearer in the final version). However
we don't know if some of the ideas in this new paper (measuring �average
wind gust� rather �average wind�) could directly affect the CLIWOC
estimations. From your experience along the CLIWOC process, do you feel
we could be overestimating, in any way, the wind in the process from the
original wind descriptor to m/s? (in the sense of comparison with
present-day anemometer averages). Some evidence of change in the wind
averages between CLIWOC and COADS data was suggested in figure 3 in the
NAO-SOI reconstruction from the �Climatic Change� CLIWOC issue, and in
figure 2 in our SLP reconstruction based on CLIWOC data in �Climate of
the Past�.

Cheers
David




Phil Jones escribi�:

>
> David,
> Do you have the daily T and Pressure data for Cadiz digitized by the
> group in Barcelona? I was never that convinced by the homogeneity
> analysis performed on the Cadiz series. This was very difficult as there
> were no other long T series for the early 19th century and Gibraltar
> seemed to have some problems with pressure in the 1820s-1850s.
>
> I still think more can be done with Gibraltar, but this is up to
> Dennis or me finding some time, which is unlikely for a good few
> years yet.
>
> There were also many gaps in the Cadiz record as in Climatic Change
> in the pre-1820 period. Have you looked at the full record, rather than
> just
> the 1825-52 period compared to 1971-2000. We see this longer term warming
> in winter further north in the Alpine region and northern Italy. In these
> regions there is little change in summer as well. What we think is
> happening
> is that the summers are too warm in the earliest years, and these should
> also show some warming. This might be less than the winters.
>
> I will show your paper to a visitor we have hear to get her view as
> well.
>
> Cheers
> Phil
>
>
> At 10:30 10/01/2007, Dennis Wheeler wrote:
>
>> David,
>>
>> Thanks for this extremely interesting item and for all your hard work. I
>> will make a more complete response next week but I'm just about to go to
>> a conference in Hull and won't be back until the weekend. It's good to
>> know that CLIWOC is still alive.
>>
>> regards and best wishes for 2007
>>
>> Dennis
>>
>> ----- Original Message -----
>> From: David Gallego <dgalpuyatXYZxyz.es>
>> Date: Tuesday, January 9, 2007 3:13 pm
>> Subject: New historical series and some post-CLIWOC results
>>
>> > Dear all,
>> >
>> > First we wish you a happy 2007!
>> >
>> > Despite we have not been in contact for a while, during the last
>> > year we
>> > have been working with some of the CLIWOC results. We found a new
>> > historical data source which provides instrumental temperature and
>> > atmospheric pressure along with estimated wind for the city of
>> > Cadiz
>> > between 1806 and 1854 (the initial year depends on the variable).
>> > We
>> > presented some preliminary results last November in the MedCLIVAR
>> > workshop hosted in Carmona and now we got almost definitive results.
>> >
>> > First, our results indicate that autumn and winter temperatures
>> > (sunset)
>> > in the city of Cadiz have risen about 2�C in the last 150 years
>> > (2.7�C
>> > in December), while summer temperatures do show almost identical
>> > values.
>> > Second, we applied the CLIWOC dictionary to convert the wind
>> > estimates
>> > in the port to m/s.
>> >
>> > The main result (apart of the fact that we could find direct
>> > translation
>> > for 99.8% of the terms found in the Cadiz archives) is that while
>> > the
>> > seasonal behavior is almost exactly reproduced, the CLIWOC-
>> > translated
>> > wind velocities are double than modern anemometer data. We believe
>> > that
>> > �at least- when used in land-based sources, the use of the CLIWOC
>> > dictionary can introduce a strong bias in the translated wind
>> > forces.
>> > Please, find our proposed explanation in the attached draft.
>> >
>> > We have some concerns about the results and we will be pleased if
>> > you
>> > could assist us with our interpretation, particularly about the
>> > following issues:
>> >
>> > 1. What is your thinking about the surprisingly strong winter
>> > warming
>> > detected? Are there precedents for similar temperature increases in
>> > Europe? (Dennis: did you find somewhat similar for Gibraltar?) To
>> > our
>> > knowledge, there is not published estimation of the urban thermal
>> > island
>> > effect in Cadiz but we think that for this city this effect should
>> > not
>> > be such strong.
>> >
>> > 2. The aprox. 2x factor in the wind estimation is applicable at the
>> > wind
>> > conversion for the city of Cadiz. Do you think a somewhat similar
>> > (but
>> > probably of much lower magnitude) wind overestimation could be
>> > affecting
>> > the current CLIWOC database? Should the situation be similar in the
>> > German Maury collection? What is your feeling about this finding?
>> >
>> > 3. Any other comment will be welcome.
>> >
>> > Thank you,
>> >
>> > Regards,
>> > David
>> >
>> >
>
>
> 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
> ----------------------------------------------------------------------------
>
>
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