Changing Trends of Aerosol Loadings Over Three Major Zones of Indian Region During the Last Seventeen Years (2005–2021)

Abstract

The spatial and temporal variation of satellite derived pre-monsoonal Aerosol Optical Depth (AOD) over the Indian region has been studied using long-term (2005–2021) satellite data from Moderate Resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI). In particular, three zones were selected, based on the dominance of natural, anthropogenic and mixture of both types of aerosols. The seasonal average of AOD (MODIS, OMI) was found to be (~ 0.40, ~ 0.35) for the entire Indian landmass. We found that the trends are increasing (and are statistically significant) over the Indian region and the increase is at a faster rate in the last 8 years compared to the previous ones. Trend from MODIS (OMI) was found to be 0.011 (0.002) year−1 and 0.014 (0.006) year−1 for the periods 2005–2012 and 2013–2021, respectively, over the Indian region. Increasing trends of AOD for zones selected in Indo-Gangetic Plains and South-India were found during 2005–2021, whereas for the desert zone, AOD trend has contrastingly became negative (2005–2012) to positive (2013–2021) in the recent years.