Future Projection of Precipitation and Temperature Extremes Using Change Factor Method over a River Basin: Case Study

Abstract

Evaluation of the changes in temporal scale and in extreme values of climatic variables is required for future hydrological modeling and policy-making. Different downscaling techniques are used to downscale global projections to the regional level but projections are not well simulated for extreme events because of uncertainty. In this study the change factor method was used on the Wainganga River Basin, because it applies the perturbations given by global climate models directly on the predictand and is able to project changes in extreme events. Statistical indices suggested by the Expert Team on Climate Change Detection and Indices were calculated to quantify the changes in the extremes for precipitation and temperature. Future assessment in dry and wet conditions was carried out using the Standardized Precipitation Index and compared with historical series. The critical observations and findings show changes in the temporal distribution of the precipitation pattern with an increase in depth for the nonmonsoon season as compared to past data. The highest variations in temperature profile were observed in winter as opposed to summer with highly frequent warm days and warm nights. In general, the climatic condition of the basin is predicted to be more humid in comparison with the past climate.