An Analysis Of The Spatial And Temporal Trends Of Precipitation From 1991 To 2020 In The Coimbatore District Of Tamil Nadu

Abstract

In this study, an investigation has been made to study the spatial and temporal variability of precipitation at Coimbatore districts of Tamil Nadu.  India over 30 years (1991-2020) on an annual and seasonal basis.  Mann-Kendal and Sen’s slope estimator tests were used to detect change over time on an annual and seasonal basis.  The cumulative deviations and Pettit-Mann-Whitney test were applied to detect possible change points.   To explore the spatial distribution of trends, each station was interpolated using ArcGIS 10.5 on a seasonal and annual basis. The highest average rainfall, continuously surpassing 1500 mm, was recorded in Cincona Valparai, Sholayar, Valparai Pap, and Valparai Taluk Office between 1991 and 2000. Additionally, the yearly rainfall trend decreased from 2011 to 2020. At 1303.89 mm, Mettupalayam continuously recorded the highest average annual rainfall despite this trend. With an average rainfall of over 1260 mm, Periyanaiken Palayam and TN-Agri came in close second and third. Despite an increase in recent decades in some areas, such as Pollachi, temporal analysis shows a drop in rainfall over the past few decades, especially during the monsoon and post-monsoon seasons over the entire Coimbatore district in 30 years. This study highlights the need for adaptive strategies in water management and infrastructure development to mitigate the impacts of changing precipitation patterns in the Coimbatore district. Understanding these trends will support better planning for agricultural productivity, water resource management, and environmental sustainability.