Thursday, June 7, 2012


cc: Eric Kreileman <>
date: Mon, 9 Oct 2000 12:52:53 +0200
from: Rik Leemans <>
subject: IMAGE climate model


In the new IMAGE 2.2 release, we discovered very strange behavior of the climate
module. At higher C02 concentrations the climate sensitivity tents to be much
less than expected. This is probably a result of our new parameterization of the
oceanic carbon uptake, which also directly influences the heat uptake.
Unfortunately, no-one in the IMAGE team is familiar with the code, the changes
that are made over the last years in order to implement the regional aerosol
effect. With the IMAGE advisory board conclusions in mind, we would still like
to continue with pursuing ECBilt but his is an long-term activity that does not
help us finalizing IMAGE 2.2.

We would therefore take you up on your suggestions during the advisory board and
start to use a simpler 0-dimensional climate/ocean model. This model should
calculate the oceanic carbon and heat uptake, In principle there are two
candidates: MAGICC and COSMIC (Maybe CLIMBER but that seems to be to difficult).
For us including a regional aerosol effect is important. The latter seems to
have a better quantification of the regional aerosol effect, but its aerosol
parametrisation is strongly dependent on Schlesingers GCM. Schlesinger does not
have an ocean uptake, but that can easily be done with the Maier-Raimer
simulations of carbon uptake.

Because of the possibility to collaborate more closely with you (and the Tyndall
Centre: I will participate in the opening ceremony) and the European funding
possibilities, we strongly prefer to start using MAGICC and the SCENGEN
approach. I would like to discuss this possibility.

We still do not have the full overview over:
- what this could mean for the coupling within IMAGE?
- what state-of-the-art regional aerosols forcing can be made?
- how about the ocean heat and carbon uptake?
- Is MAGICC than becomming the de-facto front-end model for climate-scenario
generators with Battelle and us using it?
- copy-right and other legal issues.

I will call you to tomorrow morning to discuss the possibilities with you. We
would like to move forward quite rapidly on this subject because the
finalization of IMAGE 2.2 depends on it and are eager to get your advise on this

regards, rik

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