From rmg3@access1.digex.net Mon Jul  7 21:25:16 EDT 1997
Article: 142056 of sci.environment
Path: news2.digex.net!digex.net!not-for-mail
From: rmg3@access1.digex.net (Robert Grumbine)
Newsgroups: sci.environment
Subject: Re: Question on general circulation models
Date: 7 Jul 1997 21:23:33 -0400
Organization: Under construction
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References: <33C14C94.3433@magi.com>
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Xref: news2.digex.net sci.environment:142056

In article <33C14C94.3433@magi.com>,
Tony Peluso & Ella Heyder   wrote:
>Hi:
>
>I have a question on the Canadian Climate Centre, UKMO and GFDL general
>circulation models.  When they are run under the reference scenario
>(1XCO2), is CO2 the only greenhouse gas present in the models?

  Trivially, no.  They all include water vapor, ozone, and their
radiative effects (ozone is indeed a greenhouse gas, absorbing at
9.6 microns, which would otherwise be clear to space) as well.

  Whether they include the various anthropogenically-affected greenhouse 
gasses (CFC's, methane, some nitrogen oxides, etc.) individually,
I'm not sure.  V. Ramanathan did some well-known work in the early
80's on the role these other greenhouse gasses have (i.e., ultimately
about equal to the effect of CO2 additions) on the radiative balances.
If not included individually, they're included by increasing
the CO2 level in the model by an amount equivalent to the missing
contributions from the other gasses (this being based on Ramanathan's
equivalences, and, no doubt, later work on the subject).
 
  The place to look is to do a web search for the AMIP (Atmospheric
Model Intercomparison Project) pages at LLNL.  The various (63 last
I looked, which is a while) participating models are all described in 
some detail, I believe including this question.

-- 
Robert Grumbine rmg3@access.digex.net
Sagredo (Galileo Galilei) "You present these recondite matters with too much 
evidence and ease; this great facility makes them less appreciated than they 
would be had they been presented in a more abstruse manner." Two New Sciences