Climate Change Impacts on Hydrology in Taiwan

The impacts of climate change on streamflows and groundwater recharge were evaluated for Taiwan. Rainfall unevenly distributes in a year in Taiwan Island, which May through October is a wet season and contains 67% and 90% of annual rainfall for North and South Taiwan, respectively. Increasing of frequencies of both flood and drought has been observed in recent years, which is coincided with the previous climate change impact study in Taiwan based on climate change scenarios from Country Studies Program. Further analysis of the influence of climate change on streamflows and groundwater recharge were evaluated based on IPCC­Ýs SRES scenarios in this study for providing more information of hydrologic conditions under possible future climates. Impacts on streamflows were assessed in a watershed scale by using the streamflow component of the GWLF model, while impacts on groundwater discharge was evaluate in an island wide scale by calculating water balance. Climate change scenarios were derived from three General Circulation Models (GCMs), including CGCM2 by Canadian Center for Climate Modelling and Analysis, HADCM3 by Hadley Centre for Climate Prediction and Research, and CSIRO-Mk2 by Commonwealth Scientific and Industrial Research Organization. These GCMs simulate climate based on SRES scenarios, which A2 and B2 scenarios were adopted in this study. The uncertainty of applying the predictions of global scale models and applying different GCMs are also concerned.