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Trends of Climatic Variables (Rainfall and Temperature) at Sylhet, Bangladesh

Corresponding Author : A.F.M. Kamal Chowdhury (aic_cee@sust.edu)

Authors : Salahuddin Ahmmed , Mohammod Aktarul Islam Chowdhury

Keywords : Trend, temperature, rainfall, seasons, climate systems

Abstract :

The study has evaluated long-term changes and trends in certain climatic variables such as rainfall and temperature at Sylhet. The data has been collected from Bangladesh Meteorological Department (BMD) and Climate Change Cell of the Department of Environment. For convenience of analysis, the available rainfall data (1960-2010) were divided into two halves 1960-1985 and 1986-2010 as well as temperature data (1948-2010) into 1948-2010 and 1980-2010. The rainfalls during the summer, critical period and monsoon are found to have an increasing trend by 24.5%, 33.8% and 1.13% respectively comparing the two halves of time period. The rainfall during the winter has decreased by 35.2%. The changes in seasonal rainfall are about -21.73mm, 81.68mm, - 6.92mm and 69.33mm per decade in the winter, summer, critical period and monsoon respectively. Sylhet exhibit increasing trends in mean annual temperatures given by +1.33 and +2.64 ºC per century since 1948 and 1980 respectively. In case of seasonal trend, the warmest temperature of winter, monsoon and summer within 1980-2010 shows a greater deviation from the climate line in compare to the same within 1948-80 (+70.3%, +82.4% and +44.6% respectively). The mean annual minimum temperature shows an increasing trend by 1.54 0C and 1.89 0C per century since 1948 and 1980 respectively. The monthly trend of temperature shows an increasing pattern for all months except in the case of January indicating a cooler peak winter in the recent years.  

Published on December 31st, 2012 in Volume 19, Issue 2, Applied Sciences and Technology