The distribution of aerosol optical depth in five different types was observed in and around Bangladesh as it is one of the densely populated areas in the world. For this purpose, reanalysis data of the MACC project of European Centre for Medium-Range Weather Forecasts was used for the period of 2003 to 2010. Aerosols were found to be varied in regions and seasons (pre-monsoon, monsoon, post-monsoon and winter). In addition, inter-annual variation was present. In case of seasonal variability, pre-monsoon contained more aerosols than other seasons while post-monsoon showed the least. It was observed that aerosol mostly distributed in the Western part of the study region compared to the Eastern part. Among the different aerosols, dust and sulfate aerosols were found to be contributing most in amount in the western regions during all seasons. Black carbon existed more in winter along the western area whereas sea salt was found mostly in the southern region during monsoon. Organic matter aerosols were evenly distributed among seasons and regions except in the South-eastern part. An annual increasing trend was noticed for all the aerosols except sulfate for the study period. The impacts of aerosol variability in both regions and seasons with its increasing tendency were studied which is essential for country like Bangladesh and around.
Key-words: aerosol optical depth, seasonal variability, Bangladesh, aerosol