Rainy days and rainfall intensity trends in Basar (Arunachal Pradesh) during 1979-2015

Abstract

Particularly for the Himalayan region, detail rainfall climatology is vital for assessing climate change scenario. The primary objective of current study was to investigate the seasonal and annual trends of rainy days and rainfall intensity over Basar (Arunachal Pradesh) in North-eastern Himalayan region of India during 1979-2015. Secondly it aims to evaluate the change in contributions of light, moderate, heavy and very heavy rainfall towards total rainfall. Linear regression was used for trend analysis. During the study period, no clear, consistent and significant trends in total annual and seasonal rainfall was observed over the location, but running average indicated slow increasing trends, except during post-monsoon. The annual and seasonal rainy days show decreasing trends, though not much significant during southwest monsoon and post-monsoon. The study reveal appreciable increase in rainfall intensity both in annual and seasonal scale leading to increase in extreme rainfall events in the region. During the period, it was observed that the percentage contribution of heavy and very heavy rainfall intensity class towards rainfall totals has been increasing and that of light and moderate rainfall has been decreasing. From the study it is concluded that climate of the region is changing, but the erratic trends point towards a very unpredictable and uncertain future.