Long Term Trend of Aerosol Optical Depth (AOD) over Ahmedabad and Gandhinagar: A Satellite Approach

Abstract

Satellite based observations can provide detailed knowledge in this regard on a long timescale covering a large spatial area. In this study Aerosol Optical Depth (AOD) data based on MODIS (Terra and Aqua), MISR satellite along with MERRA reanalysis product was analyzed to find out changes in the trend of AOD on urban area of Ahmedabad and Gandhinagar city from 2000 to 2018. The results strongly suggest that on this region there has been increased in AOD over the past years even though it shows a decrease during certain time period. The seasonal analysis of these cities show that the AOD is maximum in the months of summer and is minimum in the months of winter. Ahmedabad comparatively to Gandhinagar can be said a fairly polluted city. These results in general agree with the recently reported global increase in pollution- "global warming" and also the trend in some of the anthropogenic emissions.