Simulating future climate projection under HadCM3 GCM scenarios on a tropical karst island using SDSM: a case study of tropical karst catchment in Rote Island, Indonesia

A robust assessment on the impact of climate change at regional atmospheric condition is crucial to ensure the sustainability of groundwater resource for tropical karst island, where water is considered relatively scarce and thus important for the community. In this study, future long-term climate projection under HadCM3 global model climate (GCM) scenarios for a period of 2020-2090 is validated and simulated, using input data of weather variables downscaled by Statistical Downscaling Model (SDSM). The simulation indicated that the climate variables, i.e. temperature and rainfall, are expected to be affected by climate change and generally vary over the period under the scenarios. The rainfall is estimated to slightly raise by 0.14% and 0.09% under H3A2a and H3B2a scenarios, respectively. Steady temperature increases by 1.89-2.16% (Tmax) and 1.05-1.59 % (Tavg) and a decrease of 0.73-0.76% were predictable for all scenarios.