Trend and Variability Analysis of Rainfall in Thrissur Corporation

Rainfall has a great impact on the livelihood of people in subtropical countries like India. Changes in precipitation impact people and the ecosystem by altering the availability of water throughout the year. Therefore, trend analysis of rainfall has much importance in examining climate change and better planning and management of resources. The present study aimed to analyze the trend and variability of rainfall, over a period of 29 years (1991 to 2019) of Thrissur Corporation in the state of Kerala, India. In this study, the analysis was done with parametric and non-parametric methods like Mann-Kendall tests, Sen’s slope estimator and Regression analysis. Mann-Kendall tests were used to find the trend in the variability of rainfall, over the period of observation using XLSTAT software. The magnitude of variation was detected using Sen’s slope estimator. The annual and winter season rainfall were found to have a non-significant increasing trend with a positive Sen’s slope, while rainfall during summer, North-East monsoon and South-West monsoon seasons have a non-significant decreasing trend. The analysis of the impact on rainfall by temperature and relative humidity using the method of linear regression in MATLAB and SPSS software revealed a non-significant correlation of 13.8%. The results thus reveal that temperature and relative humidity have a very low impact on rainfall Of Thrissur Corporation. Other meteorological parameters like wind, solar radiation, ocean currents and factor like land use changes may influence the rainfall to a greater extent.