My primary research interest is to understand and predict monsoon from intra-seasonal to seasonal time scales. Observational data sets and coupled atmosphere -ocean general circulation models (GCM) are used for identification of the sources of monsoon variability at different spatial and temporal scales. Assessment of prediction skills and detection of model errors are used as the initial steps toward the goal of forecast improvement. Special emphasis for model development is given on convection and cloud parameterization schemes, land surface scheme and air-sea interaction. On the backdrop of climate change, studies are also undertaken to unveil the processes involved in aerosol-cloud -climate interaction. Data assimilation is also a major research topic that is being carried out for improved forecasts of monsoon intra-seasonal oscillation. Other areas of research include orographic effect on monsoon, and diurnal cycle of precipitation and clouds.