Publications

Aswini, MA; Tiwari, S; Singh, U; Kurian, S; Patel, A; Gunthe, SS; Kumar, A (2022). Aeolian Dust and Sea Salt in Marine Aerosols over the Arabian Seaduring the Southwest Monsoon: Sources and Spatial Variability. ACS EARTH AND SPACE CHEMISTRY, 6(4), 1044-1058.

Abstract
The nutrient supply to the oceanic surface water is largely regulatedby the extrinsic and intrinsic ambient atmospheric aerosol properties, particularlychemistry. In this context, we measured the comprehensive chemical composition(inorganic ions and major elements) of atmospheric aerosols and studied theirspatial distribution over the Arabian Sea during the southwest monsoon (SWM)period for 2 consecutive years (2017 and 2018). We found that the water-solubleionic concentration (WSIC) is dominated by Na+and Cl-ions followed by Ca2+and SO42-with a minor contribution of Mg2+and NO3-. The relative contributionof ionic species to WSIC remained similar for both the monsoon seasons withhigher WSIC during 2018 (69.3 +/- 63 mu gm-3) compared to 2017 (40.6 +/- 33 mu gm-3). Sea salt (estimated from Na+and Cl-ions) and mineral dust (calculated fromthe Al concentration) are dominant constituents of aerosols, with negligiblecontribution from anthropogenic species found to be temporally and spatially consistent during both the campaigns. The mineraldust is characterized by a uniform Nd isotopic signature during both campaigns, indicating its source to the Arabian Peninsula duringthe study period. Source apportionment of mineral dust using the Nd isotope is supported by back-trajectory analyses as well assatellite retrieved (MODIS and CALIPSO) data. The Cl-deficit, which is mainly attributed to the interaction of sea salt with acidicspecies, is found to be relatively low (10-12%) compared to that during continental outflow over the Arabian Sea, indicating theinsignificant contribution from anthropogenic emissions during the SWM months.

DOI:
10.1021/acsearthspacechem.1c00400

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