Author(s): Nurul Afiqah Mohamad Arbai; Masayasu Irie
Linked Author(s):
Keywords: Precipitation; Homogeneity; Trend; Peninsular Malaysia; Standardized Precipitation Index
Abstract: This study, of significant importance to the field of water resources management and environmental planning, was conducted to identify reliable stations that can be referred to for any future hydrological and hydroclimatic analysis within the east coast of Peninsular Malaysia. This region is particularly vulnerable to the climate because of its exposed location directly facing the South China Sea. The missing daily precipitation datasets were infilled using the Thiessen polygon technique to complete the long-term records sequentially. Via four established homogeneity tests: Alexandersson’s standard normal homogeneity test, Buishand’s test, Pettitt’s test, and the von Neumann ratio test, all precipitation gauges registered under the Malaysia National Hydrological Network were reviewed and checked annually and seasonally for 50 years from 1973 to 2022. It was found that 57 and 117 out of 232 stations were inhomogeneous at the 1% and 5% significance levels, hence being eliminated prior to in-depth analysis. The homogenous gauges were then applied to examine the temporal trends based on the Mann-Kendall trend test with Sen’s slope approach to identify the changes in magnitude. The trend test shows that positive trends dominated most areas over the years, except for the southwest monsoon. Lastly, the historical temporal precipitation over the study area in the past years was assessed using the Standardized Precipitation Index to measure the historical magnitude of wet and dry conditions.
Year: 2024