lmd_Li1993_abstracts.html

1993 .

R. D. Cess, M.-H. Zhang, G. L. Potter, H. W. Barker, R. A. Colman, D. A. Dazlich, A. D. del Genio, M. Esch, J. R. Fraser, V. Galin, W. L. Gates, J. J. Hack, W. J. Ingram, J. T. Kiehl, A. A. Lacis, H. Le Treut, Z.-X. Li, X.-Z. Liang, J.-F. Mahfouf, B. J. McAvaney, V. P. Meleshko, J.-J. Morcrette, D. A. Randall, E. Roeckner, J.-F. Royer, A. P. Sokolov, P. V. Sporyshev, K. E. Taylor, W.-C. Wang, and R. T. Wetherald. Uncertainties in Carbon Dioxide Radiative Forcing in Atmospheric General Circulation Models. Science, 262:1252-1255, November 1993. [ bib | DOI | ADS link ]

Global warming, caused by an increase in the concentrations of greenhouse gases, is the direct result of greenhouse gas-induced radiative forcing. When a doubling of atmospheric carbon dioxide is considered, this forcing differed substantially among 15 atmospheric general circulation models. Although there are several potential causes, the largest contributor was the carbon dioxide radiation parameterizations of the models.

E. Nesme-Ribes, E. N. Ferreira, R. Sadourny, H. Le Treut, and Z. X. Li. Solar dynamics and its impact on solar irradiance and the terrestrial climate. Journal of Geophysical Research, 98:18923, November 1993. [ bib | DOI | ADS link ]

Among the various uncertainties present in climate modeling, the variability of total solar irradiance is not one of the least. For lack of any direct measure of the solar irradiance in the past, substitutes are needed. However, the difficulties are twofold: (1) the reliability of the proxies and (2) the need for some physical mechanism relating these proxies to the solar luminosity. On the basis of a better understanding of the solar machinery we can now propose a plausible scenario connecting the exchanges of energy between the various reservoirs: magnetic, thermal, gravitational, and kinetic. In the present paper we discuss the available proxies and suggest a way to reconstruct total solar irradiance over the past four centuries. The response of the Laboratoire de Meteorologie Dynamique atmospheric general circulation model to magnetoconvective solar forcing during the Maunder minimum is discussed. The simulated cooling appears to be compatible with temperature data from the Little Ice Age; in addition, it is found that variations of globally homogeneous external forcing parameters, like incoming solar flux or greenhouse gas loading, yield climate responses with very similar geographical patterns.