21st Conference on Climate Variability and Change


Climatic Variability and Its Trend Over Different Regions of Bangladesh

Mohammad Shohrab Hossain Sarker, vrije Universiteit Brussel Belgium, London, United Kingdom

Bangladesh is a small country of South Asia which is considered as one of the most vulnerable countries in the world to climate change and it is affected by severe weather and climate events, which have tremendous impacts on the national economy. In this paper, the recent climatic variability over Bangladesh has been studied. The data of precipitation and surface air temperature for the period 1981-2003 has been used. The time series analysis was applied to investigate the variability and trend over six regions (North west & east, Middle zone, Coastal, Island and Hilly region) of Bangladesh. As a topical county there is small temperature variation in Bangladesh. But there is regional variation between northwest and south zone. In winter there exists a north-south temperature gradient which reverses during summer (pre-monsoon and monsoon). There is an extreme large seasonal variation from winter- to summer- monsoon in Bangladesh. In all seasons the difference of maximum and minimum temperature is higher in the north zone than in the south zone. A remarkable correlation was discovered between this temperature range and the rainfall occurrence. All seasons the mean maximum temperature is increasing except in winter for the northwest and middle zone (-0.004 C/year and 0.0069 C/year). Hilly region is showing highest increasing rates of mean maximum Temperature in all season (+0.075 C/ year in winter, +0.064 C/year in Pre monsoon, +0.055 C/ year in Monsoon, +0.068 C/year in Post monsoon); Where as in all season mean minimum temperature is decreasing only hilly region. Overall the temperature is increasing in whole of the country. We also find a positive trend in the rainfall, especially large during the summer monsoon and in the southern zone (in Hilly region, increasing rate of rainfall +17.78mm/year). The northwest area on the contrary is characterized by decreasing rainfall values both in winter and summer. So we can conclude that the northwest is clearly becoming more arid. May be this is enhanced by the large scale deforestation processes going on.

[Key words: Pre monsoon, Summer monsoon, Post monsoon, Maximum temperature, Minimum temperature, Precipitation]

Poster Session 6, Seasonal-interannual variability
Wednesday, 14 January 2009, 2:30 PM-4:00 PM, Hall 5

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