Dominance of natural aerosols over India in pre-monsoon: inferences from the lockdown effects

Changes in absorbing and composite aerosols over India during the first phase of lockdown are examined, using multi-satellite observations While MODIS shows –16 17 ± 1 35% reduction in AOD over the Indian landmass, OMI shows a decrease of –22 4 ± 1 36% (–26 2 ± 1 17%) in AOD (AAOD) Considerable fraction of this AOD difference is contributed by the changes in aerosols at higher altitudes While reduc-tion in AOD of –38 05 ± 1 06% (–39 4 ± 1 12), –23 02 ± 2 63% (–17 08 ± 2 12) and –18 98 ± 2 86% (–28 38 ± 2 39%) is observed over IGP, Northwest and Southern Peninsula respectively from MODIS (OMI), enhance-ment in AOD of 5 16 ± 2 44% (6 82 ± 2 86%) is seen over Centralwest India Reduction in absorbing aero-sols over IGP is –39 18 ± 1 25%, whereas that over Southern Peninsula is –33 1 ± 2 03% These changes are significantly contributed by the changes in dust aerosols, in addition to the decrease in anthropogenic aerosols Though there is a reduction in aerosol load-ing, compared to previous years, gradual increase in AOD and AAOD is seen even during the lockdown period due to strengthening of dust transport More-over, the reduction in total (absorbing) aerosol load-ing over India during the lockdown phase is only 20% (26%), with significant contribution from higher alti-tudes, even in the absence of major anthropogenic sources These results show the dominance of natural aerosols over India during pre-monsoon © 2021 All Rights Reserved