Trend Analysis of Rainfall and Detection of Change Point in Terai Zone of West Bengal

Abstract

Analyzing rainfall trends is crucial for understanding climate patterns to managing water resources and planning agriculture. Trends in rainfall can reveal shifts in climate conditions, whether it is an increase, decrease, or fluctuate over time. The present study intends to examine the long-term trend in monthly, seasonal and annual rainfall in Cooch Behar district of West Bengal spanning from 1969 to 2022. Wallis and Moore test applied to determine the randomness of rainfall, whereas, linear regression trend line, Mann-Kendall (MK) test, Modified-Mann Kendall (MMK) test, and Innovative Trend Analysis (ITA) are used to understand the trend pattern in rainfall. MMK test reveals a significant decreasing trend in November month. In contrast, the remaining months, seasonal and annual rainfall revealed non-significant trend. According to the ITA approach, there was a significant increase in rainfall of January and a significant decrease in rainfall of November and December. The Pettitt’s test identified November 2006 as a trend changing year and there was no significant change point for the remaining months, seasonal and annual rainfall.