Future Drought Projection Under Climate Change Using SPI

Abstract

Regarding Climate Change affects all regions around the world. This paper statistical downscaling was applied in drought occurrence frequency area projection. We examine 35-year past rainfall during 1971-2005 from HadGEM2-ES model under the climate change scenario CMIP5 RCP 4.5, in order to derive systematic bias. To obtain higher accuracy future rainfall (2020-2040), the systematic bias was used in correction process. We project the drought events for northeastern Thailand by using common drought index, the Standardized Precipitation Index (SPI)). Future total rainfall amount trends to equal the past, but the results show different rainfall pattern between the past and future. In the past, rainfall has a weak to moderate intensity and frequency rainy day, whereas in future rainfall has a moderate to heavy intensity and infrequency rainy day. In addition, overall SPI has a ranging between -2.0 to 2.0, moreover, SPI indicated extreme rainfall in 35 months and drought events in 35 months from year 2020 to 2040.