From: Phil Jones <p.jones@uea.ac.uk>
To: trenbert@ucar.edu
Subject: Re: Draft paper on Chinese temperature trends
Date: Tue Jan 15 14:28:18 2008
Cc: david.parker@metoffice.gov.uk, thomas.c.peterson@noaa.gov, "Reinhard Boehm" <reinhard.boehm@zamg.ac.at>, "Susan Solomon" <susan.solomon@noaa.gov>, "Adrian Simmons" <adrian.simmons@ecmwf.int>

    Kevin,
       Homogeneity only done on mean T. Lots of sites just measure this.
    A lot will measure max and min, but I haven't got the data. I also
    didn't want to get into max/min as what is relevant to urban-related
    warming in the global land series (or China) is the effects on mean T.
    I can't then look at max or min against a rural series.
       I would expect max to have changed less than min, but I can't
    really look at that.
       Also I don't want to confuse readers by saying there is an urban-related
    temp influence, but it is to a lower DTR. I guess I could refer to Vose et al
    (our Fig 3.11) which does show a decrease in DTR for 79-04 over China
    (mostly blues).
      I'll work on the text.
    Cheers
    Phil
   At 04:50 15/01/2008, Kevin Trenberth wrote:

     Phil
     I looked at the paper in more detail.   It obviously needs a bit of
     polishing throughout.
     I have a couple of fairly major comments.  The first is that you only deal
     with the mean temperature and nothing on the max and min temperatures.
     Are those available?  It would be much more powerful if those could be
     included.  The second is the special situation in China associated with
     urbanization and that is air pollution.  You do not mention aerosols and
     their effects.  We have some on that in AR4 that may be of value: refer to
     our chapter.
     In China, there has been so much increase in coal fired power and
     pollution (11 out of the top worst ten polluted cities in the world are in
     China, or something like that).  So you do not see the sun for long
     periods of time.  Presumably that greatly cuts down on the max temp but
     may also increase the min through a sort of greenhouse effect? Effects of
     urban runoff tend to warm and space heating also warms but should mainly
     affect the min.  Pollution may not be in the inner city but concentrated
     more near the sites of industry and power stations; but also may not be
     that local owing to winds?  Pollution may also change fog or smog
     conditions, and may also change drizzle and precip.  Looking at other
     variables could help with whether the changes are local or linked to
     atmospheric circulation.
     The unique aspect of urbanization related to air pollution should make
     China different, but may not be easily untangled without max and min temps
     (and DTR).
     Anyway, given these aspects, you may want to at least assemble the
     expectations somewhere altogether and discuss max (day) vs night (min)
     effects?
     Hope this helps
     Kevin
     >
     >>  Dear All,
     >          I have mentioned to you all that I've been working on a paper on
     >   Chinese temperature trends. This partly started because of allegations
     >   about Jones et al. (1990). This shows, as expected, that these claims
     >   were groundless.
     >       Anyway - I'd appreciate if you could have a look at this draft.  I
     > have
     >   spelt things out in some detail at times, but I'm expecting if it
     > is published
     >   that it will get widely read and all the words dissected. I know you're
     > all
     >   very busy and I could have been doing something more useful, but it
     > hasn't
     >   taken too long.
     >      The European examples are just a simple way to illustrate the
     > difference
     >   between UHIs and urban-related warming trends, and an excuse to
     >   reference Luke Howard.
     >
     >   Cheers
     >   Phil
     >
     >
     > 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
     > ----------------------------------------------------------------------------
     ___________________
     Kevin Trenberth
     Climate Analysis Section, NCAR
     PO Box 3000
     Boulder CO 80307
     ph 303 497 1318
     [1]http://www.cgd.ucar.edu/cas/trenbert.html

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

References

   1. http://www.cgd.ucar.edu/cas/trenbert.html

