Rainfall intensity duration frequency curve for Sungai Layang catchment under climate change

Abstract

This paper study on the development of intensity duration frequency (IDF) curve at study area of Sungai Layang catchment by using the annual maximum rainfall data (mm) for 20 years rainfall data from 1980 to 1999 years by using the observed rainfall data and the simulated rainfall data obtained from Global Climate Models (GCMs). The frequency analysis was conducted by using the rainfall data in determining the best suited type of data distribution by using empirical and theoretical (Normal, Lognormal and EV1- Gumbel) distribution which applied the frequency factor method for obtaining the magnitudes of extreme events. These distributions were been used to fit rainfall data with 2, 5, 10, 20, 50 and 100 years return periods. Two global climate models which consist of ECHAM5 and CCSM3 models were involved in this study to determine the best model that was suitable for rainfall analysis in this study area. The study shows that EV1 Gumbel distribution was the most fitted distribution to describe the daily rainfall patterns in study area. Besides, the study also resulted that ECHAM5 model was more suited to be used with lower RMSE value compared to CCSM3 model. Therefore, for future research involving climate change study using global climate models, the rainfall simulation using ECHAM5 was validated to be used for rainfall analysis.