Climate of Bangladesh: An Analysis of Northwestern and Southwestern Part Using High Resolution Atmosphere-Ocean General Circulation Model (AOGCM)

Abstract

The past, present and future climatic pattern (temperature and rainfall) of northwestern and southwestern part of Bangladesh was assessed based on the High Resolution Atmospheric-Ocean General Circulation Model (AOGCM) using the present rainfall and temperature data of the Bangladesh Meteorological Department (BMD). Climatology in Bangladesh is derived from 20 km mesh MRI-AGCM (Atmospheric General Circulation Model) calibrated with reference to the observed data for the period of 1979-2006. Then, projections for rainfall and temperature are made for near future (2015-2034) and future (2075-99). Two disaster prone areas (i) northwestern part (Shapahar & Porsha) and (ii) southwestern part (Kalapara & Amtoli) were selected as the study areas. AOGCM model was run for Bangladesh and also for study areas separately. The present mean temperature for Bangladesh was found to rise from the past, rises slightly, but in near future and future the rate of mean temperature rise is projected to be much more than the present rate (increase up to 4.34 °C/100 years), the rate is projected to be 5.39 °C/100 years in case of Shapahar and Porsha a while 4.37 °C/100 years in case of Kalapara and Amtoli. The present, near future and future average rainfall of Bangladesh appeared to fluctuate, but have shown a decreasing trend (decreases up to 1.96 mm/100 years). The mean average rainfall of Shapahar and Porsha presently decreases very slowly (not significant), but in near future and future will decrease slowly (0.66mm/100 years). In case of Kalapara, the average rainfall appears to decrease presently, near future and future will decrease up to 3.62 mm/100 years. The average rainfall of Amtoli appears to decrease @ 1.92mm/100 years but in near future appears to increase slightly and again decrease @ 3.27mm/100years in future.

Keywords: Atmosphere-Ocean General Circulation Model (AOGCM); climatology; simulation; temperature; rainfall

DOI: http://dx.doi.org/10.3329/agric.v9i1-2.9489

The Agriculturists 2011; 9(1&2): 143-154