Simulation of future climate variations using global circulation model and downscaling model

Abstract

Precipitation is the main cause of variability in the water balance over space and time on the earth surface, and changes in precipitation have important implications for hydrology and water resources. Precipitation varies in space and time as result of the general circulation patterns of atmospheric circulation and local factors. This study proposes the application Statistical Downscaling Model (SDSM) using three sets of data to investigate the climate variations. The data are the observed daily data of large-scale predictor variables, National Centre for Environmental Prediction (NCEP) and Global Circulation Model (GCM) simulations from Hadley Centre 3rd generation (HadCM3). The records of daily precipitation data (1961-1990) are from five stations namely, Ldg. Allagor, Pusat Kesihatan Kecil, Stn. Petak, Ldg. Gedong and Ldg. Gula. Those stations are located in Perak, Malaysia. The HadCM3 data starts from 1961 to 2099 were extracted for 30-year time slices. The results of SDSM downscaling model on precipitation have shown that the differences exist between current observed data and future periods (2020’s, 2050’s and 2080’s) for the five stations. The observed parameters are mean daily precipitation, wet days percentage, wet spell and dry spell with the future simulated climate data for the periods 2020’s, 2050’s and 2080’s. The differences can be recognized between the observed and simulated mean daily precipitation for the future periods 2020’s. The SDSM model is generally feasible and reliable for use in downscaling of precipitation in Perak, Malaysia.