Experiments in numerical modelling of the Pacific sea surface temperature anomalies

By using the atmosphere-ocean coupled model (CGCM) which is composed of a 2-level global atmospheric general circulation model and a 4-layer Pacific oceanic general circulation model developed in the Institute of Atmospheric Physics of Chinese Academy of Sciences, and two model climatological fields got from the two independent models' numerical integrations respectively, the Pacific sea surface temperature anomalies (SSTA) from 1988 to 1989 are simulated in this paper with observed atmospheric general circulation data and sea surface temperature fields as initial conditions and monthly coupling scheme. In order to remove systematic biases of the model climatological fields, interaction variables between atmosphere and ocean are also corrected simultaneously. The experiments show that the simulation results can be improved effectively if these interaction variables are corrected in spite of the fact that there always exist systematic biases in independent numerical simulations of atmospheric part and oceanic part within CGCM. The basic characteristics of the observed Pacific SSTA in September and October 1988 have been simulated by using the correction scheme, such as the negative SSTA domain in the whole Equatotial Pacific east to 150°E and the positive SSTA domain in the Western Pacific, the northern subVopical Pacific and nearly the whole Southern Pacific. Further numerical simulations show that the model can simulate not only the SSTA in the Pacific and its seasonal variations but also iu interannual changes (for example. La Nino event in the Equatorial Pacific teturinated after May 1989) to a certain degree. Furthermore, some problems existing in experiment processes and what we shoud do in the following stage are also discussed and analysed in this paper.