TRENDS OF TEMPERATURE AT HIGH- AND LOW-DENSELY POPULATED DIVISIONS IN BANGLADESH

Abstract

Trend, Temperature, Mann-Kendall test, Sen's slope estimate, Bangladesh:The present study is carried out to determine the trends in changes in temperature at Dhaka and Khulna divisions in Bangladesh using non parametric Mann-Kendall test for the period 1960-2015. Temperature is considered as one of the most important climatic variables in terms of climate change. Results show increasing trends in all monsoon seasons (pre-monsoon, monsoon and post monsoon season) for both divisions. Highest increasing rate is found in post monsoon season at Dhaka division with Sen’s slope estimate 0.27 oC/decade which is statistically significant at 99% level. Winter season shows increasing trend at Dhaka division whereas decreasing trend at Khulna division. The highest decreasing rate at Khulna division is -0.06 oC/decade which is statistically insignificant. In the month of January, trends of both divisions are decreasing. The increasing trend in central and high populated-industrial Dhaka division and decreasing trend in southern low populated-nonindustrial Khulna division is due to characteristics of the two divisions. The warmest year is 2010 for both Khulna and Dhaka divisions. The coldest year is 1981 for Khulna division while 1971 for Dhaka. The decadal change of temperature indicates that the colder season experiences lowest temperature whereas warmer season experiences highest temperature day by day. This is a clear indication of climate change in the region. The study for the trend of another valuable climatic parameter precipitation is recommended to understand the impact of climate change across the country.