TREND AND VARIABILITY OF RAINFALL: AN ANALYTICAL STUDY OF PASCHIM BARDHAMAN DISTRICT, WEST BENGAL, INDIA

Abstract

Analysing trend and pattern of rainfall variability is crucial for detecting changes in microclimate, predominantly in places having experienced with unprecedented rate of urbanization and expansion of built-up areas. It has a pivotal role in water availability and water stress management in dry region like the western part of West Bengal. The present paper aims to analyse the trend of rainfall over last four decades (1981- 2022) of Paschim Bardhaman district of West Bengal using Innovative Trend Analysis (ITA) method. This graphical method is quite effective for assessing hydro-meteorological trends of time series data as it overcomes the issues like length of data, normality and independent structure of time series. To identify the seasonal and annual variability of rainfall in the study area, the pre-monsoon, monsoon, post-monsoon, winter and annual rainfall data have been plotted on Cartesian coordinate system. The ITA plots have been further categorized into different clusters and the magnitude of slope has also been calculated for each season. The ITA of pre-monsoon, monsoon and post-monsoon seasons indicate an increasing trend while in winter a negative trend of precipitation is detected. The ITA of total annual rainfall of the district exhibits an increasing trend. The research work will be supportive for water resource planners and policy makers for judicious utilization of available water resources in the study area.