date: Fri Oct 2 14:40:37 2009 from: Phil Jones subject: Re: # stations in HadCRU to: Gerard van der Schrier 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 ----------------------------------------------------------------------------