The Variability of the Historical and Future Temperature in Bangladesh

Abstract

Aims: To discern how the historical temperature varied over the time period from 1975 to 2014 and what kind of temperature profile Bangladesh may prevail in the future. Study Design: This study was designed to reveal how the monthly mean of the daily average, monthly mean of daily maximum and monthly mean of the daily minimum temperature of all divisions covering all hydrological units of Bangladesh changed historically. It is also designed to forecast the all type of temperatures up to 2050 using Box Jenkin’s algorithm in IBM SPSS. Place and Duration of Study: This study was conducted within the time period from December 2015 to December 2016 under the Department of Civil Engineering, Dhaka University of Engineering & Technology, Gazipur, Bangladesh. Methodology: At first the daily average, daily minimum and daily maximum temperature for the time period 1975 to 2014 of 13 stations, covering all hydrological units of Bangladesh, were converted in to monthly mean and then graphs of individual months were plotted and analyzed afterwards. To infer the historical temperature variations clearly over the entire time period, histogram of the decadal averages of the each type of temperature of the individual months were also plotted. Finally, the monthly records were forecasted up to 2050 by a time series model using Box Jenkin’s algorithm in IBM SPSS. Results: Based on the historical and projected temperature, this study revealed that winter became colder especially in January and the summer got hotter over the time which may continue in future. By 2050 the maximum temperature may rise by 1.50±0.3℃ in summer, average temperature may rise by 1.0±0.3℃ and minimum temperature may vary by -0.8±0.3℃ in winter. Conclusion: This study concludes that winter may get colder in the northern part as well as some southern part of Bangladesh and reverse may suit for the summer where January and April would be the coldest and the hottest months respectively in future. By the year 2050, the average temperature may rise by 1.0±0.3℃ and the maximum temperature may lead by 1.50±0.3℃, whereas the minimum temperature may vary by 0±0.2℃. Overall, Bangladesh would experience a comparatively warmer weather in the coming decades.