Kaustuv Mukherjee


South-west monsoon dominated eastern India has considerable variation of rainfall occurrences through time. Being a state of eastern India, West Bengal is not an exception in this case with its vast areal extent (88,752 sq. km.). This is a state of vast physiographic and climatic differences. Keeping these things in mind, present study focuses on the trend analysis of rainfall over all the districts of West Bengal for the 20th century. Mann-Kendall trend statistics is used to show the trend and Sen’s estimator of slope is used to depict the magnitude of the trend. Lastly, a simple co-relation among the weather variables has been done to show the impact of rainfall in changing hydrological conditions of the state. The result shows that most of the districts have a downward trend of rainfall although the rainfall in the South-Bengal has an increasing trend. Over-all, rainfall in the monsoon period has decreased and it has increased in the post-monsoon period. Maximum decreasing trend of monsoon rainfall in the last century is seen in the Maldah district (at the rate of 0.509 mm. per year) and maximum increasing trend is seen in the North 24 Parganas district (at the rate of 0.344 mm. per year). In the past century, rainfall has a negative co-relation with temperature, potential evapo-transpiration and reference crop evapo-transpiration.


Rainfall Trend, Season, Mann-Kendall Trend Statistics, Sen’s Slope, Co-relation.

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