date: Fri Oct  2 14:40:37 2009
from: Phil Jones <p.jones@uea.ac.uk>
subject: Re: # stations in HadCRU
to: Gerard van der Schrier <schrier@knmi.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.jones@uea.ac.uk
   NR4 7TJ
   UK
   ----------------------------------------------------------------------------

