Quantifying Trends of Historical Climatic Variables in the Jessore Region of Bangladesh
Md. Nuruzzaman
Bangladesh Food Safety Authority, Bangladesh.
Most. Sifat Muntaha Soni
Department of Statistics, Islamic University, Kushtia, Bangladesh.
Md. Shohel Rana
Department of Statistics, Islamic University, Kushtia, Bangladesh.
Ahsanul Haq
Department of Statistics, University of Barisal, Bangladesh.
Md. Matiur Rahman Molla *
Department of Statistics, Islamic University, Kushtia, Bangladesh.
*Author to whom correspondence should be addressed.
Abstract
The aim of the study was to detect trends in salient key climate variables in the Jessore region of Bangladesh for the years 1985–2014, and the data was collected from the Bangladesh Meteorological Department (BMD). Annual rainfall, annual maximum temperature, and annual cloud coverage were analyzed using the non-parametric Mann-Kendall test, linear regression, and LOWESS curve to detect trends in the series. The rainfall and cloud coverage showed a decline trend at a rate of (4.50 mm/year; 45.02 mm/decade) and (0.045 octas/year; 0.45829 oktas/decade), respectively, whereas temperature manifested an increment trend (0.0285°C/year; 0.2854°C/decade), where cloud coverage was the only significant variable. The structural breakdown point was found using the graphical method and the Chow test, which showed in 2004 that both the series containing breakdown points and cloud coverage exhibit statistical significance.
Keywords: LOWESS curve, Mann-Kendall test, Chow test, Breakdown point, trend