Recent winter warming over India - spatial and temporal characteristics of monthly maximum and minimum temperature trends for January to March

In the backdrop of recent warmer winters over India, temperature series of 174 stations well distributed over the country were statistically analyzed to document the long term variations and trends in monthly mean maximum and minimum temperatures for January to March. From the trend analysis, February month has emerged as the warmer winter month over North India where increase in both maximum (+0.29 degrees C / decade) and minimum (+0.38 degrees C / decade) temperatures is highest with noteworthy increase in maximum temperature at a rate 1.5 times that of the South India averaged increase. Spatially, North India minimum temperature trends for February and March and South India maximum temperature trends for all months are more coherent. Both day-time and night-time total cloud amounts are increasing significantly over Indo-Gangetic plains and south peninsula and decreasing significantly in central and east India. However increase in temperatures over extreme south peninsula in January and March is difficult to explain on the basis of increase in day-time total cloud amount indicating strong influence of other climatic factors. At the same time, sea surface temperatures of the Arabian Sea and the Bay of Bengal are rising and there is strong positive correlation between land surface temperatures and sea surface temperatures suggesting significant contribution of warmer sea waters which may have important climatic implications over neighbouring regions.