Rainfall trend analysis using the Mann-Kendall test with pyMannKendall: A case study of Jeli, Kelantan

Abstract

Trend analysis was widely used as a tool to detect changes in climatic and hydrological time series data such as rainfall. Therefore, this study aims to analyse the rainfall trends in Jeli, Kelantan from 2009 to 2020 Simple linear regression was used to impute missing data in all rainfall stations. The rainfall trends in time series were tested using the Mann- Kendall test and Sens’ slope methods. This analysis was analysed using Python with pyMannKendall package. Kg. Jeli exhibited a statistically significant decreasing trend in rainfall, with a Kendall’s Tau of -0.1412 and a Sen’s slope of -0.0272 (p-value = 0.0121). However, no statistically significant rainfall trends were observed in the other three rainfall stations: Ldg. Kuala Balah, Kg. Gemang Bahru, and Kg. Ayer Lanas during the study period. Generally, this study concludes that the flood event was caused by high rainfall intensity.