Features and trends of rainfall in recent 20 years at different locations in humid tropical to subtropical asia

Abstract

Monthly rainfall data of the last 20 years were obtained for 16 locations in Thailand, and for 7, 4, and 1 location(s) in Indonesia, Bangladesh, and Viet Nam, respectively, under tropical to subtropical monsoon and tropical rainforest climates. They were used to calculate the average and variability of rainfall at those locations and to examine the recent rainfall trend by application of the first regression analysis. The rainfall trend, expressed as a regression coefficient of the first regression equation, was only significant at some locations, but the positive rainfall trend was identified at locations in Peninsula Thailand, whereas the negative rainfall trend was indicated for locations in Sumatra and Java Islands of Indonesia. At locations under tropical to subtropical monsoon climate, the significant trends in the annual and seasonal rainfall were hardly indicated, but the large annual variability of rainfall was observed in the dry-season.