date: Mon Jan 17 10:10:42 2005
from: Phil Jones <p.jones@uea.ac.uk>
subject: Fwd: Re: Fwd: Rainfall trends
to: "Klein Tank, Albert" <Albert.Klein.Tank@knmi.nl>

    Albert,
       Maybe you have this attachment - maybe not. I thought I would send
    on as it relates to how we should or should not refer to Michaels et
    al (2004) which came out in IJC in last issue of 2004.
    Cheers
    Phil

     Date: Sun, 16 Jan 2005 14:54:32 -0500
     From: "Thomas R Karl" <Thomas.R.Karl@noaa.gov>
     User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624
     Netscape/7.1 (ax)
     X-Accept-Language: en-us, en
     To: Thomas R Karl <Thomas.R.Karl@noaa.gov>
     CC: Phil Jones <p.jones@uea.ac.uk>,
               Pasha Groisman <Pasha.Groisman@noaa.gov>
     Subject: Re: Fwd: Rainfall trends
     X-UEA-MailScanner-Information: Please contact the ISP for more information
     X-UEA-MailScanner: Found to be clean
     X-UEA-MailScanner-SpamScore: ss
     Sorry Phil --- pdf version attached
     Thomas R Karl wrote:

     Phil,
     Thanks for the article and note.  I refer you to our latest work (lead author Pasha)
     which is attached.  Here you will see we have expanded our network to include all the
     data we have been digitizing over the past few years.  We have far more stations than we
     had in 1998 and were able to search for trends in the higher quantiles with longer
     return periods.   Our results clearly show  stronger trends compared to the mean the
     higher in the distribution you go (see Tables 1 through 4).  In addition, we find (I
     calculated this from Table 3 in our paper) that when you compare 1910-1970 with 1971-99
     you find relative to the mean annual total precip during the two periods the 99.9
     percentile value accounted for 12% more precip in the later period (relative to the mean
     of that period) compared with the 99.9 percentile and the mean of the earlier period.
     For the 99th percentile it was 9% higher in the later period and for the 95 percentile
     it was 5% more.  Also you can see the trends at the higher percentiles increasing much
     fast thatn for the mean.
     I note Pat's Fig. 4a the sign of the change is consistent with our results (not sure
     about magnitude because he uses inches (WHO REVIEWED THIS AND LET HIM GET AWAY WITH
     INCHES!!)), but when he divides by the total annual precip the results are quite
     different. I am not sure how much his small network of 129 stations contributes to
     unstable results.  Second, if you look at our Table 1 we show the national trend in the
     mean to be about 6% per Century (consistent with IPCC and the US National Assessment).
     I suspect his method of averaging is misleading him, and a few stations with high 10-day
     precip compared to the mean within the regions are dominating and causing unstable
     results.  We found that in looking at the extremes one really has to be careful how one
     does area averaging.
     Phil, if you simply look at the trends for the 95, 99 and 99.9 percentiles all our
     increasing at a much faster rate from 17 up to 33 percent per century.  The
     intepretation is straightforward, the heaviest precip events are increasing faster than
     the mean (again consistent with Katz's theoretical work and Pasha's earlier empirically
     based model we featured in IPCC 2001).  .
     So... I am not sure we need to respond to Pat's work as I think our latest is much more
     comprehensive.  What do you think?
     P.S.   I think we are close to sending our Vertical Temp Report out next week.  I will
     send you, Kevin, and Susan copies.  It was far more work than I ever imagined and we are
     just in our first review stage!
     As you can see thinks are pretty busy ---- seem to be working too much as I am sure you
     are!---- at least on weekends I am up here on the Mountain which makes up for a lot.
     Regards, Tom

   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
   ----------------------------------------------------------------------------
