Subject: Tracer data (N2O, CH4, etc loss rates)
From: Sheo S. Prasad (ssp@CreativeResearch.org)
Date: Tue Dec 22 1998 - 01:17:59 MST
Dear Colleagues:
I am trying to run CCM3.6.6 with changes in the way N2O, CH4 and CFCs
are currently handled. I have started making the new N2O and CH4 loss
rates arrays as functions of latitude, altitude and months based upon
the new chemistry of N2O (GRL, v25, p4333, 1998) and related
considerations. But I need help with the following matters:
(1) In what units should I create the loss rate?
(2) The way in which the array should be prepared. Should the month,
latitude, and the altitude (pressure) be the 1st, 2nd, and the 3rd
elements? Or, should it be latitude, pressure and month?
(3) After I create the array, how do I convert into a netCDF file
compatible with the ccm3.6.6? What program to use? I could be wrong, but
the tools library that came with the standard distribution does not
contain a tool appropriate for this task. So, I need some help in terms
with an access to the tool that has been used at either NCAR or NOAA for
this purpose. Also, what other special information will I have to supply
to the tool in order for it to do the task correctly?
(4) I see that in the chemini.F subroutine, just after the comment
obtain tracer dataset and open file, there is a statement:
trcdata='noaamisc.r8.nc'
Knowing that the N2O loss rates came from the NOAA 2D-model
(Solomon-Garcia), I get the feeling that noaamisc.r8.nc is the file that
contains the N2O, CH4 etc. loss rate data. Thus, I will have to either
name my data set also as noaamisc.r8.nc or I will have to modify the
chemini.F and change that particular statement. Is this correct? By the
way:
(a) What is the significance of r8 in the name of the NOAA data set?
(b) Is it that if I create the new dataset for N2O then I will have to
make it complete with the same information for all others tracers as
well?
(5) Until now the loss rates for N2O, CH4 and CFC11 and CFC12 are
strictly the loss rates due to reactions with O(1D) and
photodissociation. In my case it will have to be net loss rates for N2O,
i.e., N2O production rates - N2O loss rates. Any problem from the
CCM3.6.6's point of view?
(6) I am having difficulty in figuring out what is the situation with
respect to N2O, CH4 and CFCs in the standard distribution of CCM3.6.6.
On the one hand the standard distribution does not contain the file
noaamisc.r8.nc referred to in the chemini.F subroutine. Thus, these
species cannot be run. On the other hand, water is always done, and its
tendency is twice the tendency of CH4. So by implication, if water is
always done then CH4 must also be always carried. Then the dilemma is
how CH4 done when the noaamisc.r8.nc is not in the standard
distribution?
(7) If N2O, CH4, and CFC's are not done normally, then in order to
activate their treatment will I have to recompile the code after
changing the TRXX etc.? If they are actually being done, then where how
are the corresponding results outputted?
Your help will be greatly appreciated.
Best regards.
Sheo
(Sheo S. Prasad)
CREATIVE RESEARCH ENTERPRISES
Website URL: http://www.CreativeResearch.org
Phone: 925/426-9341; Fax: 925/426-9417
e-mail: ssp@CreativeResearch.org
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