Analysis of Trend in Maximum and Minimum Surface Air Temperature in Medinipur Division of West Bengal, India

The main objective of this study is to examine the trends in mean monthly and mean annual minimum and maximum air temperature in all the five districts of Medinipur Division, West Bengal. To accomplish this, the study utilizes the IMD gridded daily minimum temperature data available at grid resolution of 1°x1° in binary format from the official India Meteorological Department (IMD) Pune website. The study area encompasses 16 grid points and for each point the concerned parameters were analysed for the period between 1951 and 2020 by using Mann-Kendall test and the trend magnitude was measured by Sen’s slope estimator. The results of maximum air temperature show that for monsoon and post-monsoon months, the dominant warming effect is experienced (p < 0.05, α=0.05, n = 70) across all districts with exception in a few pockets, whereas significant cooling tendency is noticeable at same significance level for winter and pre-monsoon months, particularly during December-January and April-May. This conflicting temperature trends in two different seasons makes the annual mean maximum series trendless. In case of minimum air temperature, a cooling effect is dominant in the summer months across all the districts. Significant warming tendency is noticeable in the monsoon and post monsoon particularly during July to September and November. Annual mean minimum series shows an overall increasing trend. However the warming rate (0.0080C to 0.8950C per year) is likely to be higher than the cooling rate (0.0100C to 0.7230C per year)