Characteristics of Temperature and Rainfall in Bangladesh: A historical Perspective 1948-2011

Abstract

Climate change is regarded as the greatest long-term threat to the development of Bangladesh. The article provides an assessment of climate change and variability based on analysis of historical data of temperature and rainfall recorded at 34 meteorological stations located at seven regions in Bangladesh for the period of 1948-2011. Analysis of temperature data showed an increasing trend in the yearly average temperature at majority of these stations. During this period, the yearly average temperature in the country increased by 0.52°C at a rate of 0.01°C per year. The magnitude of increase in monthly average temperature from 1976 to 20011 of the total study period was sharply higher than the average. Moreover, significant increase of maximum temperature was observed in Khulna and Barishal, whereas, minimum temperature was recorded in Sylhet and Rangpur. The rainfall difference from 1953 to 2011 was -107.71 mm. Post-monsoon rainfall showed an increasing trend during the period of 1953-2011 in majority of regions. In contrast, there was a decreasing trend in total rainfall during monsoon. There was no significant change in pre-monsoon total rainfall. In general, these trends are consistent with the general climate change predictions. The maximum rainfall significantly increased in Sylhet and Chittagong while minimum rainfall was recorded in Khulna and Rajshahi regions. The temperature and rainfall patterns are of great importance for an agro-based economy like Bangladesh. Moreover, these changes will threaten the significant achievements. There was an inverse and positive relationship between the average temperature and values of SOI and IOD. These observations are particularly significant in the context of Bangladesh where agriculture is heavily dependent on temperature and rainfall patterns.