- Dona Paula, Goa, India.
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| Abstract Submission No. | ABS-2022-08-0245 |
| Title of Abstract | Aeolian dust and sea-salt in marine aerosols over the Arabian Sea during the southwest monsoon: Sources and spatial variability. |
| Authors | Aswini M. A.*, Shani Tiwari, Udisha Singh, Siby Kurian, Sachin S. Gunthe, Ashwini Kumar |
| Organisation | CSIR-National Institute of Oceanography, Goa, |
| Address | B-27, NIO colony panaji, Goa, India Pincode: 403004 Mobile: 9637337547 E-mail: aswinianirudhan.10@gmail.com |
| Country | India |
| Presentation | Oral |
| Abstract | The nutrient supply to surface water of oceanic region depends on the ambient atmospheric aerosol concentration and associated chemistry. In this context, we report chemical composition (inorganic ions and major elements) of atmospheric aerosols and their spatial distribution over the Arabian Sea during southwest monsoon (SWM) period. Water soluble ionic concentration (WSIC) is dominated by Na+ and Cl- ions followed by Ca2+ and Mg2+ with minor contribution of SO42- and NO3-. The relative contribution of ionic species to WSIC remain same for both years, although higher WSIC is observed during 2018 (70.0±63.5µgm-3) compared to 2017 (40.7±32.9µgm-3). Sea salt (estimated from Na+ and Cl-ions) and mineral dust (calculated from Al concentration) are dominant constituent of aerosols, with negligible contribution from anthropogenic species, during both campaigns. Almost similar spatial distribution of sea-salt and mineral dust is observed for both years with maximum average concentration in the northern sector of the Arabian Sea. The mineral dust is characterized by a uniform εNd signature (~ -6) during both campaign indicating their sources to the Arabian Peninsula during south west monsoon month. Source approtionment of mineral dust using Nd isotope is supported by back-trajectory analyses as well as satellite retrieved (MODIS and CALIPSO) data. The Cl-deficit which is mainly attributed to the interaction of sea-salt with acidic species is found to be relatively low (10-12 %), compared to those during reported during continental outflow over the Arabian Sea, indicate insignificant contribution from anthropogenic emissions during the SWM months. |