APPLICATION OF BIAS-CORRECTION AND DOWNSCALING METHOD TO KALU GANGA BASIN IN SRI LANKA

Abstract

Climate change impact assessments for regional or local studies are mainly based on the general circulation models GCMs under the different emission scenarios. Downscaling of selected GCM after bias-correction can address the gap of resolutions with some merits and limitation for application at basin-scale hydrologic simulation. This paper describes how to select the appropriate GCMs and how to develop bias-correction and downscaling method for GCMs precipitation. Bias-corrected scheme removes the large bias of GCMs precipitation. This method of downscaling is also comparable to the basin scale mean intensity,annual precipitation and inter-annual monthly precipitation. All of corrected GCMs rainfall presented the increasing trend not only in extreme rainfall but also in seasonal climatology in the Kalu Ganga basin in near future.