cc: Francis Zwiers <Francis.Zwiers@ec.gc.ca>
date: Fri Oct  1 09:20:07 2004
from: Phil Jones <p.jones@uea.ac.uk>
subject: Re: Global warming
to: "Fudge, Dennis  WLAP:EX" <Dennis.Fudge@gems6.gov.bc.ca>

    Dennis,
       Hopefully you can read pdf files. The attachment and maybe some of the references in it
   will
    give you the answer to your question(s).
       Each station is in one of our grid cells (5 by 5 deg. of lat/long) and we use anomalies
    (departures) from the 1961-90 period (12 monthly averages for each station). Some boxes
   are
    based on many stations, some on just one. The paper refers to another in JGR from 2001
    (Jones et al., 2001) that adjusts the variance of the series to account for differing
   station
    numbers over time. You can read a little more about this on our web site
    [1]http://www.cru.uea.ac.uk then go to data, then to temperature. There are a number of
   other
    FAQs there as well. We do a small amount of extrapolation - see the paper.
        I have cc'd this message to Francis Zwiers, who is the Canadian Govt scientist (at
   Victoria)
    you might like to contact for further info. He was involved in a project to adjust
   Canadian
    temperature data for many of the problems of site changes and observational practice
    changes that have occurred over the years. For Canada, we have incorporated this dataset.
    We try to include as much of this work as possible, but for a lot of countries we have to
   do this
    work ourselves. This is sub-optimal as we don't have all the necessary metadata (data
   about
    data), but we do the best we can.
       I will be travelling much of October, but if you have any additional questions email
   me. Francis is
    also likely travelling as well, but he should be also able to answer most questions.
    Cheers
    Phil
   At 18:38 28/09/2004, you wrote:

     I have been trying to find information of how the temperature trends are
     calculated. I have contacted several people from the Canadian Federal
     Government but no one was able to
     answer my question.
     I know the temperatures are average for each grid cells. But using just one
     grid cell as an example und using only land stations and ignoring the
     weighting applied; If there were 10 meteorological stations in that cell in
     1970 and there are now 7 stations, are only those seven station used for
     every year? Or are all stations used when ever available? If all stations
     are used, is there an effort to extrapolate for the now none operational
     stations?
     Dennis Fudge
     Air Pollution Meteorologist
     Ministry of Water, Land and Air Protection
     250-565-4210
     If you woke up breathing, congratulations! You have another chance!

   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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