Newsletter No.4 October-1998

Ms.Yoko Tsushima
Hello there !
One of the purpose of our Global Warming Research Group is to describe variations of mechanisms of different climates such as present period,the last maximum and minumum period of near surface temperature(the last glacial maximum, the mid-Holocene),double CO2 period and to understand the mechanisms of climate change by simulating each climate with the General Circulation Model (GCM)and analyzing the results.Among the analysis,I take note of roles played by cloud and radiation in the climate variations.
Radiation budget at the top of the atmosphere is the first factor to determine climate,and clouds are the key element which contributes largely to the budget.I analyse variations of clouds in different climate,variations of radiative fields by it,and their relation with large-scale fields.It is a good way to use GCM in analyzing the climate change,but it is also necessary to confirm if responses of parameters to it are described properly in it or not.
It has been pointed out that the different parameterizations of cloud water result in a dispersion of estimates of variations in ground surface temperatures by the CO2 warming in GCMs.
I proceed with analysis of the relation between the atmospheric field and the amount of cloud water in seasonal variations, which are climate variations with fairly big signals and of which observational data are obtainable.
I evaluate the models by using their results,and expect to verify points to be improved in parameterization.

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