Author(s): Md. Rezaul Karim; Sakib Shadman Prosun; Ahmed Farhan Mahabub
Linked Author(s):
Keywords: Climate change; Rainfall trend; Extreme events; Statistical analysis; Bangladesh
Abstract: Bangladesh is considered as one of the worst vulnerable country affected by global climate change, which may cause a significant shift in the rainfall pattern and trend of the country. Variation in quantities of precipitation is often assessed by detecting and characterizing trends in available metrological data. This study was undertaken to analyze the historic annual rainfall data of the country and observe the trend for annual, seasonal and extreme rainfall. Daily rainfall data of 11 metrological stations from 1965-2015 distributed all over the country was collected and analyzed for seasonal and annual rainfall variation. Co-efficient of variation (CV) and standardized anomaly index (SAI) were used to evaluate rainfall variability, while Mann-Kendall test and Sen’s Slope model were used to detect the trend and magnitude of rainfall change, respectively. It was observed that about 69% of rainfall occurs during the Monsoon season throughout the country. Post-Monsoon season shows a significant increasing trend in rainfall, whereas Pre-Monsoon, Monsoon and Dry season show significant decrease in rainfall. Mean annual rainfall was highest in Sylhet; whereas Rajshahi has the least mean annual rainfall. Annual mean rainfall in Bangladesh was found to be 2347 mm/year. Moreover, a non-significant trend has been found in annual mean rainfall all over the country. Monthly mean and extreme rainfall were also analyzed and it was found a decreasing trend for the extreme event. In case of annual, seasonal and extreme rainfall, most of the stations show negative treads, thus indicating that the rainfall is decreasing all over the country over 51 years study period.
Year: 2020