Tropical Intraseasonal Variability Simulated by IPCC AR4 Climate Models

Tropical atmospheric intraseasonal variability plays an important role in the tropical climate system. In a series of studies, we have evaluated the tropical intraseasonal variability in more than a dozen coupled general circulation models (GCMs) participating in the Inter-governmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). The modes we studied include: (1) The all-season Madden-Julian Oscillation (MJO) and convectively coupled equatorial waves; (2) The Asian summer monsoon and associated subseasonal modes; (3) The North American monsoon and associated subseasonal modes; and (4) The African monsoon and associated subseasonal modes. We will report the main results of these studies, and discuss about the possible ways to improve the model simulations. The results may also be useful for people in other fields who are going to use the IPCC AR4 simulations in their studies.

References:

Lin, J. L., G.N. Kiladis, B.E. Mapes, K.M. Weickmann, K.R. Sperber, W.Y. Lin, M. Wheeler, S.D. Schubert, A. Del Genio, L.J. Donner, S. Emori, J.-F. Gueremy, F. Hourdin, P.J. Rasch, E. Roeckner, and J.F. Scinocca, 2006: Tropical intraseasonal variability in 14 IPCC AR4 climate models. Part I: Convective signals. J. Climate, 19, 2665-2690.

Lin, J. L., M.-I. Lee, D. Kim, and I.-S. Kang, 2006: The impacts of convective parameterization and moisture triggerring on AGCM-simulated convectively coupled equatorial waves. J. Climate, in press.

Lin, J. L., B.E. Mapes, K.M. Weickmann, G.N. Kiladis, S.D. Schubert, M. J. Suarez, J. Bacmeister, and M.-I. Lee, 2007: North American monsoon and convectively coupled equatorial waves simulated by IPCC AR4 coupled GCMs. J. Climate, accepted with minor revisions.

Lin, J. L., K.M. Weickmann, G.N. Kiladis, B.E. Mapes, S.D. Schubert, M. J. Suarez, J. Bacmeister, and M.-I. Lee, 2007: Subseasonal variability associated with Asian summer monsoon simulated by 14 IPCC AR4 coupled GCMs. J. Climate, revised.

Lin, J. L., and others, 2007: Subseasonal variability associated with African monsoon simulated by 14 IPCC AR4 coupled GCMs. Mon. Wea. Rev., to be submitted.