Drought Forecasting Using SPI and EDI under RCP-8.5 Climate Change Scenarios for Langat River Basin, Malaysia

In Malaysia, droughts often lead to water deficit and overcoming a lack of fresh water has become one of the important challenges in the country. Climate change have brought about a big environmental impact globally, such as the rise in sea levels, unavailability of fresh portal water and more extreme drought and flood events occurring and Malaysia is no different and not spared all this calamities. The Langat River Basin is located in a fast growing region in Peninsular Malaysia, the Greater Kuala Lumpur Valley and hence the implementation of the drought index in this basin is vital important and necessary. Normally drought characteristics can be determined or identified using the drought indices. The two drought indices were used in this study, namely the SPI (Standardized Precipitation Index) and the EDI (Effective Drought Index) to assess the severity, duration and extend of drought event. The CanESM2 outputs under Representative Concentration Pathway (RCP) 8.5 emission scenario of IPCC Fifth Assessment Report (AR5) were utilized to produce regionalized precipitation and temperature data. The GCM outputs were statistically downscaled using the Statistical Downscaling Model (SDSM) version 4.2.9. Next, the SPI for time scale period of 1-month, 6-months and 12-months (SPI-1, SPI-6 and SPI-12) and EDI were calculated for both the observed and statistically downscaled climate data to investigate and analyze the severity and extent of drought. Both indices were compared to get a more operational index between SPI-1, SPI-6, SPI-12 and EDI outlook for representing Malaysia drought events.