Frequency and Trend Analysis of Rainfall Data for Kochi, Kerala, India

Abstract

Rainfall is a crucial component of many engineering designs, including hydraulic structures, water conservation structures, bridges and culverts, canals, storm water sewers, and road drainage systems. To estimate the relevant input value for crop planning as well as engineering structure design and analysis, a thorough statistical analysis of each region is necessary. The current study includes statistical analysis, namely frequency analysis of Kochi's seasonal rainfall data. Weibull's method is used to evaluate the designed value of rainfall based on daily rainfall data collected over a 20-year period. The mean, standard deviation, and coefficient of variation are computed to estimate the fluctuation in rainfall. The moving average method and probability distribution method are used to analyze the rainfall trend in annual and monthly time series. Over the course of these 20 years, September had the lowest mean monthly rainfall (59.16 mm), while June had the highest mean monthly rainfall (899.13 mm). June had the lowest coefficient of variation (CV), followed by July, while September had the highest coefficient of variation (CV). For the entire time period under consideration, it was found that the monthly rainfall for the selected Kochi was lower in September than in the other months. June and July had higher monthly rainfall than any other month over the whole study period.