Friday, June 1, 2012

4748.txt

date: Fri Oct 2 14:40:37 2009
from: Phil Jones <p.jonesatXYZxyz.ac.uk>
subject: Re: # stations in HadCRU
to: Gerard van der Schrier <schrieratXYZxyzi.nl>

Gerard,
I've been trying not very successfully this week to write a paper for a talk I agreed
to give in Berlin in April next year on Climate Change in Europe. David and Dimitrios are
doing loads of plots for me. My mistake was not reading the small print which said, we'd
like a 20 page paper as well! As they are paying me a not insignificant amount in Euros
(which is now much more in pounds) I'm trying to get the paper done for their deadline.
Anyway the reason for telling you is that I've put in a good plug for ECA&D real-time
extreme monitoring. The web site looks good and the few series I looked at worked well. I'm
referring to a report which has you and Albert on, with Aryan as first author. I'm also
going to add in a bit on PDSI across Europe. Do you have a European average time series of
the areas with PDSI > 2 and 4 and -2 and -4? Is this in one of your papers? I've looked at
all I can think of and can't see it. Hopefully PDSI is scPDSI and with Penman. Europe can
be defined anyway you want. I told Dimitrios 30W to 60E and 30-70N for some maps he's
doing. If you've something to hand for a smaller Europe then that would be fine.
Cheers
Phil
PS Have you submitted the paper about Penman/Thornethwaite scPDSI or are you
Dutch-skepticked out?
PPS I presume some Dutch skeptics have their minds made up, whatever you say.
At 14:23 02/10/2009, you wrote:

Dear Phil,
That's o.k., I can imagine that you are getting fed-up with these comments and emails.
We don't envy you.
Cheers, Gerard

Gerard,
I probably got carried away earlier! Possibly this relates to the issues with Keith
and Yamal currently doing the rounds. I've been getting lots of snide comments via email
for the past couple of weeks. People have no idea of the literature and they get their
info from skeptic web sites. It just appals me how people believe the rubbish on climate
audit. People think they have discovered something new, but it's been known for years.
We weren't the first to show some of these things. Koeppen realized about spatial
degrees of freedom.
Cheers
Phil
At 14:12 02/10/2009, Gerard van der Schrier wrote:

Dear Phil,
Many thanks for the lecture.
Usually, I try to get as far away as I can from skeptics.......
Cheers, Gerard

Gerard,
Philip has answered your points for the skeptics and clearly stated that the overall
count of stations is not that important. It is where they are. We could increase the
number of sites in the US and Australia, but it is a matter of putting effort into where
it does most good. We will get more in at some stage.
Related to this - the papers talk about WMO 10-year books. When the one for
2001-2010 gets done we will add that in as soon as available, as it will make a
difference. It won't be a real book, but a dataset from NCDC. It won't be available till
about 2012.
Several years ago I got all my old papers as pdfs from AMS and AGU. I've attached a
couple of these. I know these skeptics don't read the literature, but you could point
out that even in the first paper on this that we did we showed a plot (for land only)
that is essentially the same as one of Philip's. This is just to point out that if they
went back and looked at the literature they would see that we have thought of these
things before. We just don't put them all in every paper.
The second from 1994 shows that you can reproduce the hemispheric averages from land
data with just 5% of the data. Figure 8 and the text around it are the key here. This
got extended to a paper in 1997 where the concept of spatial degrees of freedom got
introduced.
I've been meaning for the last couple of years to do this again, but it's never got
to the top of my pile as I know the answer! This is that I could take several sets of
100 different stations (each set well spaced across the world) and when averaged they
would all look much the same. We all know this, but it seems that many of the skeptics
don't. Another way of looking at this is - does any skeptic consider why MBH or any
other hemispheric reconstruction works when there are only between 50 and 100 proxies?
If they did they might then realize that 50-100 perfect proxies (i.e. thermometers)
would do even better than 50-100 imperfect proxies.
This is also shown in Jones, P.D., Briffa, K.R., Barnett, T.P. and Tett, S.F.B.,
1998: High-resolution palaeoclimatic records for the last millennium: interpretation,
integration and comparison with General Circulation Model control run temperatures. The
Holocene 8, 455-471.
Here endeth the lesson

Go forth my child and convert the skeptic world
Phil

At 10:03 02/10/2009, Brohan, Philip wrote:

Hi Gerard.
I enclose figures showing the fractional coverage of HadCRUT3 and the
number of stations that go into the land component (CRUTEM3), together
with data files so you can replot the figures if you want. Feel free to
use these in correspondence with sceptics. The data files I made these
from are on the web at [1]www.hadobs.org.
HadCRUT3 is a blended land and sea dataset, and the basic records that
go into the two components are different, the land component (CRUTEM3)
is made from monthly average station records, and the sea component
(HadSST2) is made from instantaneous ship and buoy observations. So it's
not really meaningful to talk about the number of stations in HadCRUT3 -
you have to look at the two components separately.
I think what I was trying to say about the number of stations is that
the change in the number of stations is not directly useful as an
indication of the value of the resulting dataset. We are less worried
than we might be about the large reduction in the number of stations in
recent years, because many of the stations we lost were in North
America, where coverage is still good even without them - we worry more
about loss of stations where there are few to start with. I've copied
this message to Phil Jones, who might be able to put this better.
Regards,
Philip
-----Original Message-----
From: Gerard van der Schrier [ [2]mailto:schrier@knmi.nl]
Sent: 01 October 2009 07:16
To: Brohan, Philip
Subject: # stations in HadCRU
Dear Philip,
It was very nice chatting with you during the ACRE workshop - sorry for
getting back at you this late.
During one of the coffee breaks, we discussed the number of stations
that went in the HadCRU global temperature record. In that discussion,
you mentioned that Phil Jones tries hard to keep the number of stations
above a critical level, but can't afford to spend much time to keep the
number of stations much higher than this critical level. This has had
the affect that the number of stations used in HadCRU increases until
the 1970s, and then decreases again. Would you have a graph of that
curve?
In your presentation, you also had a graph with the percentage of 5x5
degree gridboxes which had at least one "station" vs. time. Could we
use both figures in our correspondence with the Dutch climate sceptics?
Cheers,
Gerard
--
----------------------------------------------------------
Gerard van der Schrier
Royal Netherlands Meteorological Institute (KNMI) dept. KS/KA PO Box 201
3730 AE De Bilt The Netherlands [3]schrier@knmi.nl
+31-30-2206597
[4]www.knmi.nl/~schrier
----------------------------------------------------------

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 [5]p.jones@uea.ac.uk
NR4 7TJ
UK
----------------------------------------------------------------------------


--
----------------------------------------------------------
Gerard van der Schrier
Royal Netherlands Meteorological Institute (KNMI)
dept. KS/KA
PO Box 201
3730 AE De Bilt
The Netherlands
[6]schrier@knmi.nl
+31-30-2206597

[7]www.knmi.nl/~schrier
----------------------------------------------------------

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 [8]p.jones@uea.ac.uk
NR4 7TJ
UK
----------------------------------------------------------------------------


--
----------------------------------------------------------
Gerard van der Schrier
Royal Netherlands Meteorological Institute (KNMI)
dept. KS/KA
PO Box 201
3730 AE De Bilt
The Netherlands
[9]schrier@knmi.nl
+31-30-2206597
[10]www.knmi.nl/~schrier
----------------------------------------------------------

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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