SEASONAL MONSOON FORECAST FOR THE YEARS 1987 AND 1988

The results of several seasonal integrations with an atmospheric globa l circulation model with prescribed ''perfect'' sea surface temperatur es are presented. These experiments illustrate the results of seasonal simulations for the years 1987 and 1988. These were a dry and a wet m onsoon year, respectively, when compared to the average. The integrati ons cover the period from June 1 through August 31 for both years and were carried out at two horizontal resolutions, T42 and T106, of a glo bal model containing two different parameterizations of surface hydrol ogy. The seasonal differences of the motion fields, divergent circulat ions and rainfall distributions for these respective experiments are c ompared with the corresponding observed fields. The sensitivity of sea sonal simulations to the initial state is explored with integrations s tarting on two successive dates. in these experiments we diagnose diff erences of the simulated time mean states from residue free budgets of the complete vorticity equation.