In this paper, the author present an assessment of the likely climate changes over the Indian subcontinent and the intraseasonal and interannual variability in summer monsoon rainfall as a consequence of increasing greenhouse gas concentrations in the atmosphere as inferred from CSIRO9 climate model simulations. The data obtained from the control and doubled CO₂ experiments with the model, each for 24-equilibrium years, are analyzed in this study.
The model demonstrates a reasonable skill in simulating the present-day climate and its interannual variability over the Indian subcontinent. The total seasonal rain ll over India under the influence of southwest monsoon activ­ity as inferred from the control run is in fair agreement with the observed climatology. A rise in area-averaged surface temperature of 2.98° during the monsoon season over India (for land points only) is projected by the model in a doubled C0₂ atmosphere. Though no significant change in the monsoon onset date is found, an intensification of monsoonal rainfall is simulated by the model in a warmer atmosphere. The seasonal changes in the other hy­drological parameters (evaporation and soil moisture) simulated by the model for the doubled C0₂ atmosphere are also discussed.