date: Sat, 25 Jul 1998 13:50:58 -0400
from: Richard Goldberg <ccrag@nasagiss.giss.nasa.gov>
subject: GCM WWW site
to: m.hulme@uea.ac.uk

Mike:

      Here are a few more questions/ comments about down-loading the GCM data
from the WWW. It is Saturday. I was able to download files quickly from 7am-
11 am New York time, but unlike last week, I was unable to download any more
files after that (11am - 1:30 pm NY time). It kept getting stuck in certain
places.

     There appears to be an error in the CCCM data. The precipitation
values are
very small (.1E-5 for example). This cant be. The Solar radiation values also
look funny. They continually decrease, instead of decreasing towards the
poles.
(Unless maybe I have done something wrong?)

     It would be helpful to include a note saying what the difference is
between
the average temperature and just taking (tmax+tmin) / 2.

      I was just re-reading some of the notes on using HADCM2 Results (the
document that you gave us in February of 1997.) Many of the suggestions in
there about how to form the climate change scenarios are very different than
the way that we have normally done things. we usually use a 100 year control
run as the base and ten years of data to represent the altered green-house
gas decades. We use differences for temperature and ratios for precipitation
and solar radiation.
     So, in line with this, let me see if I understand your methodology
completely.
Your suggestion for creating the GCM climate change scenarios on the Web
is to use differences only, thirty year slices of data at a time, both for the
control and altered data. So in order to get the climate changes for the 2020s
for example, I have to average the 3 decades (2010-2039) of the increased
green-house run and compare that to 1961-1990 of the control run. Is that 
correct?
       Is there any way that I can obtain a sample value or two from the
scenarios
to check to make sure that in the proccess of downloading and manipulating the
data I have not mangled any of the results?
       As far as maps are concerned, we usually are primarily interested in
annual changes in the various variables, over the world, for each scenario.
The maps that we make are usually in color, (and sometimes black&white)
Sometimes we use maps of specific continents only. Uusually annual
temperature,precip, and solar radiation change.

                                                      Yours truly,

                                                       Richie Goldberg