Indian Monsoon Rainfall Projections for Future Using GCM Model Outputs Under Climate Change

Statistical downscaling technique is used for projection of Indian monsoon monthly rainfall (IMMR) at 0.25 resolution using 3 General circulation model outputs (GCMs) of Coupled Model Intercomparison Project Phase 5 (CMIP5) suite. General circulation models (GCMs) are the best tools available now to study the climate variables at coarse/global level. But these GCMs are poor at studying climate at fine/regional/local level. A statistical model, which relates large-scale climate variables (or predictors) to regional/local-scale climate/hydrologic variables(or predictand), is developed to derive the regional information about the climate/hydrologic variable. In the present study the projection is carried out based on a linear regression model in which statistical downscaling relation is developed between the standardized NCEP/NCAR data and APHRODITE observed precipitation. The relationship thus developed is applied to the GCM simulated output for projection of rainfall in the future. The results obtained from 3 GCMs are combined with multi model average (MMA) are represented in plots showing the change in the mean rainfall between the historic period (1980-2000) and future period (2010-2040). The probable distribution function (PDF) of MMA data is plotted for all over India. The present study highlights the IMMR projections in the effective management of water resources in the future due to impact of Climate change.