Spatio-Temporal Variability and Trends of Rainfall by South-West Monsoon over North Bengal Region

The study is an attempt to investigate the spatio-temporal variations and trends in the occurrences of rainfall due to south-west monsoon over different districts of North Bengal. The spatial variation of rainfall is very distinct in all the districts which also indicate different landuse practices in the area. Past 50 years record of rainfall indicate a dramatic change in the rainfall pattern over this region which shows a change in its intensity and frequency. The area is characterised by three important seasons, namely Pre -Monsoon Period (March-May), Monsoon Period (June-September), and Post Monsoon Period (October-December). Statistical techniques like coefficient of variation and regression slopes have been used to show the variability of rainfall pattern. For better understanding, the results are then incorporated in GIS based maps to show the asymmetry in the rainfall distribution pattern in the region. These observations of changing occurrences of weather events demonstrate regional climate change.