date: Thu May 20 13:56:35 2004
from: Phil Jones
subject: Re: [Fwd: Re: Paper on ERA-40/NCEP/CRU comparisons]
to: Adrian Simmons
Adrian,
Methinks they try to defend their paper too much ! The comment didn't say they are
wrong, just not justified.
Their argument about assimilation of the surface temperature data doesn't work either.
Your report shows that changes in input data (surface and satellite and sondes) affects
the fields. So, how do they prove that their differences are due to urbanization and
land-use changes and not data inputs. The differences between CRU and ERA-40 can
hardly be said to be gradual. You've explained most of them by data input changes. The
jumps with NCEP are larger and there are more of them.
I'm here today and tomorrow then off next week. Back for the whole of June and
July (except for a fortnight when the house move occurs). If you want to give me a
call after June 1 then do. How soon can the report go to press?
Also, do you intend to go to Geneva for GIP in August?
Cheers
Phil
At 23:04 18/05/2004 +0100, you wrote:
Ming, Eugenia
I'm travelling also, and do not have a copy of your Nature paper with me.
I have looked at Fig 16 however. It does show a rise in the NH in the difference between
temperature at two metres and near the top of the boundary layer. But the rise occurs
principally rather sharply in the first half of the 1990s, not what I would have
expected from an affect of change in land-surface use, and it is seen also in the
simulation, which did not have any change over time in prescribed land characteristics.
Unless there is simply chance agreement between the simulation and the reanalysis I
suspect that there is some effect from the SST/sea-ice analysis at play here.
The plot corresponding to Fig 16 but restricted to North America is attached.
Best regards
Adrian
cai wrote:
Dear Adrian,
Eugenia is on travel. I am not sure if she would be able to check her email in time to
response your
email. Anyhow, this is my response to two additional questions of yours, which follows
after your
original questions below.
Regards.
Ming Cai
On May 17, 2004, at 5:46 PM, Adrian Simmons wrote:
Dear Ming and Eugenia
Thanks for your comments, which I'll take note of when I revise the text of our paper in
a week or two.
I am puzzled, though, by your second comment. I do not understand the reference to Fig
6a, which does not relate to the trend above the boundary layer. The relevant figure is
Fig12b,which shows a very similar trend over North America at the surface and at level
49. The trend is a little lower at 500hPa (attached), but not much.
I'd appreciate it if you could clarify this point.
We meant Fig. 16 instead of Fig. 6 in our comment letter. Looking at Fig. 12b or the
figure you attached in your last email, I have to agree that the difference between
ERA40 2 meter temperature and level 49 temperature indeed
is small (I understand that the former is subject to the second tier assimilation and
the latter results from the primary data assimilation system. This is indeed very
impressive result). However, if we look at the red curve in Fig. 16a, we do see the
difference between the 2-meter temperature and level 49 temperature increases in time
over NH. From that plot, one can conclude that the 2-meter temperature warms at a fast
rate than that at the level 49. Perhaps, we didn't interpret that figure correctly. I
appreciate if you could help us to interpret that figure.
Also, with regard to your fourth point, strictly speaking I did not write that our AMIP
run argued against an effect of land-use change; I actually wrote that it did not
support your conclusions. That was intended as a more netral comment, as one might
indeed have reservations as to the conclusions one can draw from imperfect model
simulations, just as one might have reservations about what can be deduced from
imperfect reanalyses.
Yes, we understand that that result is neutral in the context of our Nature paper is
concerned. However, if you put that result in the context of our Nature paper,
particularly saying that it didn't not support
our conclusion, that would make the result NOT "neutral", which is a concern of ours.
Best regards
Adrian
cai wrote:
Dear Adrian,
Attached is our response to your manuscript. Thanks again
for sharing the manuscript with us. We are looking forward to
more discussion on this subject.
Regards.
Ming Cai
On Apr 25, 2004, at 3:36 PM, Adrian Simmons wrote:
Dear Ming
Thanks for the response. Unfortunately I shall not be at the EGS meeting. I myself will
be travelling from 6 to 21 May, but hope to check my email from time to time while away.
I will not take our manuscript any further until I have heard from you and Eugenia, but
would like at least to publish it as an ERA-40 report (with or without reference to your
work) as soon as I get back.
Best regards
Adrian
Ming Cai wrote:
Dear Adrian,
Thanks for sending the manuscript to us. Since I will be in EGS meeting next week,
Eugenia and I would not be able to get together to discuss your paper till my return
from the trip.
Meantime, I assume that you may be also attending the EGS meeting at NICE. If so,
we could have a lunch or a brief discuss during the break. I will present a paper
co-authored with Eugenia at 9:00AM on Thursday (April 29) morning in Session CL11
(Lecture Room Euterpe). The title is "Can reanalysis have anthropogenic climate trends
without model forcing?" I think your work strengthens our arguments.
I look forward to meeting with you and discussing with you on implication of your
work on our Nature paper and on the work I am presenting at the EGS meeting.
Regards.
Ming Cai
by "Cai, M; Kalnay, E"
has been scheduled for an oral presentation in Session CL11,
Lecture Room Euterpe on Thursday, 29 April 2004, 9:00.
On Apr 23, 2004, at 5:53 PM, Eugenia Kalnay wrote:
-------- Original Message --------
Subject: Re: Paper on ERA-40/NCEP/CRU comparisons
Date: Fri, 23 Apr 2004 22:30:07 +0100
From: Adrian Simmons
Organization: E.C.M.W.F
To: Eugenia Kalnay
References: <40894D36.2030005@ecmwf.int> <40897810.90705@atmos.umd.edu>
Thanks for the initial response, Eugenia. I won't reply fully now, but
will wait for your detailed comments.
One thing though. I did note you replied to the comments in the
references, but certainly could flag this in the text also. But let's
see whether the references to your Nature letter survive at all. Maybe
you'll convince me to say nothing.
And a second. I show in the paper that the trace of temperatures over
North America at model level 49 (about 850hPa for 1000hPa surface
pressure) are virtually the same as at the surface. The level-49
analysis is hardly affected at all by the fact we did a separate
analysis of two-metre temperature using SYNOPS. There's just a weak
affect at this level from the soil-moisture and soil-temperature
analysis. Am I wrong to expect that land-use changes would affect
near-surface temperatures but have less impact on temperatures at the
top of the PBL?
There's no chance of the paper being submitted for at least a month.
I'll be wearing my computer-buying hat in the US and Japan before then.
Best regards
Adrian
Eugenia Kalnay wrote:
Dear Adrian:
This is a very preliminary response, since my coauthor is away, and I would like to
consult with him, and prepare a detailed response/comments, which we will send hopefully
next week. I only gave your draft a very fast first reading.
Nevertheless, I'll give you a first quick response:
First I completely agree with you that ERA-40 should indeed be better than NNR! It
better be!!!! So I don't have any quarrel with the results that you present. Hopefully
the next global reanalysis will be even better...
However, I think that your conclusions about the support or lack of support of your
results to those of Kalnay and Cai (2003) are not appropriate or fair: Our method is
*totally* based on the fact that the NNR surface temperature was completely independent
of the observed surface temperature, which is evidently not true in the ERA-40, where
the observed surface air temperatures did influence the soil temperature and moisture.
Therefore, the only thing that you can conclude is that our method (unfortunately)
cannot be applied "as is" to the ERA-40 reanalysis. For example, the fact that the NNR
has a larger amplitude intra-annual variability is in agreement with the assumption that
the NNR surface temperatures don't "know" about the increased heat capacity brought by
land surface changes. Note also that we do not apply our method to the Rockies, since
evidently the NNR surface temperature estimation is not good at all over regions with
steep orography and cannot be used.
Since you list the criticisms of Trenberth and Vose et al, it would be fair to quote as
well our strong responses. (We first had to correct many serious errors of understanding
that they made in their first critical comments). We have also received hundreds of very
positive comments as well, and one very famous scientist here and his team did a very
careful study over China with our method, with very similar results to ours, and with
remarkable agreement between the land surface changes estimations from our method, and
changes in population and agriculture.
There are a number of other points that I would like to make, and Ming Cai will have
many insightful comments as well... Thanks for showing this to us first... Please don't
send it for publication until we clear out our disagreements, or at least agree to
disagree...
With warm regards,
Eugenia
Adrian Simmons wrote:
Eugenia
I'd appreciate any comments you might have on the attached draft, particularly the
second paragraph of the introduction and the last paragraph of the conclusions. I take
all the blame - the first the co-authors will see of these two paragraphs are when they
respond to the mail below. I hope I have the story straight - I'm certainly open to
changing it if not. I also hope that the paper in general does not come across as trying
to "do down" the NCEP/NCAR reanalysis - ERA-40 is a much more recent reanalysis, and it
would be strange if it did not improve on the NNR in some ways. Here again, I'm open to
suggestions for changes in wording.
Best regards
Adrian
-------- Original Message --------
Subject: Paper on ERA-40/CRU comparisons
Date: Fri, 23 Apr 2004 17:53:53 +0100
From: Adrian Simmons
Reply-To: Adrian.Simmons@ecmwf.int
Organization: ECMWF
To: Phil Jones , ers@ecmwf.int,
erp@ecmwf.int, Anton Beljaars , Vanda Da Costa Bechtold
, Sami Saarinen , Pedro Viterbo
, Nils Wedi
CC: dib@ecmwf.int
Phil and ECMWF colleagues
Attached is a reasonably polished version of a paper comparing CRU,
ECMWF and NCEP analyses of surface air temperature. Many of you have
seen a much earlier version. It's in a format that we can put out
quickly as an ECMWF project report, after which I think it's worth
turning it into a Journal article, which will entail at least dropping a
lot of colour from the plots, and probably a few of the time series.
I'd appreciate your comments on the paper as it stands for an ERA-40
report, and any suggestions as to what might be cut (or added) to make a
paper for ? Journal of Climate. I've tried to address comments
received from Phil on an early draft. One specific question for Phil: Do
you have the full author list for the Turner et al. paper? I'll send a
copy to Eugenia, as I would not want to put this on the web without
giving her a chance to respond to the remarks about her letter to Nature
with Cai.
Are you all happy with the author list? I hope this is not too much of a
surprise for Sami and Nils. I think Sami deserves to be there for
writing the OI T2m analysis in the first place and for his observational
database work for ERA-40, and Nils deserves to be there for getting the
AMIP-style simulation done, which I think adds quite a bit to the paper.
Best regards
Adrian
--
--------------------------------------------------
Adrian Simmons
Head of Data Division
European Centre for Medium-Range Weather Forecasts
Shinfield Park, Reading, RG2 9AX, UK
Phone: +44 118 949 9700
Fax: +44 118 986 9450
--------------------------------------------------
--
Eugenia Kalnay
Distinguished University Professor
Department of Meteorology
University of Maryland
3431 CSS Building
College Park, MD, 20742-2425
tel: 301-405-5370/5391; fax:301-314-9482
ekalnay@atmos.umd.edu; [1]http://www.atmos.umd.edu/~ekalnay
Home: Malise Dick and Eugenia Kalnay
56 Lakeside Dr
Greenbelt MD 20770
tel/fax 301-313-0208
--
--------------------------------------------------
Adrian Simmons
Head of Data Division
European Centre for Medium-Range Weather Forecasts
Shinfield Park, Reading, RG2 9AX, UK
Phone: +44 118 949 9700
Fax: +44 118 986 9450
--------------------------------------------------
Ming Cai
Associate Professor
Department of Meteorology & School of Computational Science and Information Technology
Florida State University
Tallahassee, FL 32036
Email: cai@met.fsu.edu, cai@csit.fsu.edu
Phone: (850)-645-1551, FAX: (850)-644-9642
--
--------------------------------------------------
Adrian Simmons
Head of Data Division
European Centre for Medium-Range Weather Forecasts
Shinfield Park, Reading, RG2 9AX, UK
Phone: +44 118 949 9700
Fax: +44 118 986 9450
--------------------------------------------------
--
--------------------------------------------------
Adrian Simmons
Head of Data Division
European Centre for Medium-Range Weather Forecasts
Shinfield Park, Reading, RG2 9AX, UK
Phone: +44 118 949 9700
Fax: +44 118 986 9450
--------------------------------------------------
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.jones@uea.ac.uk
NR4 7TJ
UK
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