Trending Regional Precipitation Distribution and Intensity: Use of Climatic Indices

Abstract

Trends and variability of\rannual precipitation total, annual number of rainy days and two climate change\rrelated precipitation indices named Simple Daily Intensity Index (SDII) and\rPrecipitation Concentration Index (PCI) have been investigated in this study.\rThe analysis was based on daily and monthly precipitation data of 35\robservatory stations all over Bangladesh for the study period of 1971-2010.\rMann Kendall test was performed to detect the trend and Sen’s slope method to determine\rthe magnitude of change. The results indicate statistically significant (95%\rconfidence level) negative trend in 4 stations and significant positive trend\rin 2 stations for annual precipitation total. Significant positive trend in 9\rstations for annual number of rainy days, significant negative trend in 6\rstations for SDII and for PCI, and significant negative trend in 6 stations\rwere found all over Bangladesh in this study. The values of PCI indicate\rstrongly irregular precipitation distribution in South Eastern Region (SER) and\rmostly irregular distribution in other regions. On the other hand values of\rSDII indicate strong precipitation intensity in SER and mostly moderate\rintensity in other regions all over the country.