Historical Analysis and Future Projections of Meteorological Drought in Northeast Thailand Using Statistically Downscaled Climate Models

Abstract

Drought is a reoccurring meteorological hazard that seriously affects agricultural production, water resources and the livelihoods of rural people. The current study investigates the past, observed drought conditions as well as future climate change scenario in Northeast Thailand by combining historical meteorological observations, satellite-derived precipitation datasets, and statistically downscaled Global Climate Model (GCM) outputs. The SPI based on fitting the Gamma-distribution and through probability-of-normal transformation was employed in 12-month periods to describe drought severity and duration from 1994 to 2023. Future scenarios were projected using CanESM2 (CMIP5) and CanESM5 (CMIP6) under RCP4.5 and RCP8.5 emission pathways for mid-century (2041–2070) and late-century (2071–2100) periods. The accuracy of the climate projections was improved through bias correction via Quantile Mapping (QM) and empirical downscaling with Multiple Linear Regression (MLR), with calibration and validation of the mod