Spatial distribution of meteorological droughts in the Kirindi Oya basin of Sri Lanka with implications of climate change

Abstract

The study centers on scrutinizing the spatial distribution of meteorological droughts within the Kirindi Oya dry zone river basin of Sri Lanka, considering the prospective impacts of climate change. The CNRM-CM6-1-HR climate model was selected based on the performance to assess the future drought susceptibility of the Kirindi Oya basin. To generate maps for the future, gridded rainfall datasets were developed using Climate Hazards Group InfraRed Precipitation (CHIRPS) satellite data under the Shared Socioeconomic Pathways (SSP) scenarios, specifically SSP1-2.6 and SSP5-8.5 projection scenarios. The bias correction for CHIRPS satellite data was performed using a non-linear power transformation approach while the mean-based method was used for the bias correction of Global Climate Model data. Then the Standardized Precipitation Index at a three-month scale was used to estimate meteorological drought conditions. According to the results, the basin is more vulnerable to moderate droughts in the 2015-2100 period under the SSP1-2.6 scenario. The occurrence of severe droughts in the middle part of the basin is significant under the SSP5-8.5 scenario. Additionally, the frequency of occurrence of extreme droughts is projected to increase by more than 35% under both projection scenarios. Therefore, proactive planning and risk mitigation are crucial for effective basin water resource management.