Author(s): Chaminda Samarasuriya Patabendige; So Kazama; Daisuke Komori
Linked Author(s): So Kazama
Keywords: Global climate models (GCMs); Monsoon seasons
Abstract: This paper presents the potential effect of climate change on the annual and seasonal runoff and associated uncertainties in 49 river basins of Sri Lanka for the near future period of 2021–2050. Five Global Climate Models (GCMs) driven by three Representatives Concentrate Pathways (RCPs) were statistically downscaled and used to project the potential climate change responses to the annual and seasonal runoff. A distributed hydrological model was used to simulate the natural runoff for the baseline (1976-2005) and future time periods. The uncertainty was evaluated by employing ensemble averaged GCM climate projection under three RCPs to represent climate changes on precipitation, potential evapotranspiration and runoff. The results show that annual runoff of the Sri Lanka has a high probability of increasing in the near future. However, the prediction of the mean annual runoff from year 2021 to2050 increases from 6%to 15.5%, depending on the river basin and for the applied RCP ensemble. There was a high level of consensus for increased runoff during the southwest and second inter monsoon seasons. The projected runoff showed both increasing and decreasing trend depending on the applied RCP ensembles during the first inter and northeast monsoons.