Trends in Precipitation Characteristics in Bangladesh from 1950 to 2008

Abstract

We analyzed trends in precipitation characteristics at 12 weather stations in Bangladesh using data from 1950 to 2008 and a non-parametric Mann-Kendall's tau test. It was found that the annual precipitation amount and the number of wet days tended to increase at almost all the stations. The number of days with weak precipitation (< 3 mm) showed increasing tendency; the number of days with daily precipitation exceeding 10 mm increased at three stations; and the number of days with daily precipitation exceeding 20 mm increased at two stations. Heavy rainfall index showed no clear trend, and was dominated by inter-annual and/or decadal variations. During the pre-monsoon season, seasonal precipitation amount and the number of wet days increased, and the number of days with weak precipitation (< 3 mm) also increased. Changes in the monsoon and post-monsoon seasons were insignificant.