This study examines the optical and chemical characteristics of south Asian outflow across the northern Indian Ocean during the northern hemispheric winter of the year 2018, as part of the Integrated Campaign for Aerosols, gases, and Radiation Budget (ICARB) experiment. Our observations reveal a significant influence of anthropogenic aerosols on columnar aerosol optical depth (AOD) in the equatorial Indian Ocean, with anthropogenic AOD accounting for approximately 46 % of the composite aerosol load. Water-soluble anthropogenic ions (WSAI) emerge as the primary contributor to columnar AOD across most oceanic regions of the northern Indian Ocean, attributed to their high scaling distance compared to other dominant species such as organic carbon (OC) and black carbon (BC). The assessment of speciated aerosol radiative forcing indicates the primary contribution of BC to surface forcing in coastal regions, with WSAI (followed by BC and OC) exerting dominance in far oceanic areas. Overall, anthropogenic forcing, primarily from WSAI, OC, and BC, accounts for a substantial portion of the total forcing at the top of the atmosphere (72 %) and surface (89 %) over most of the cruise regions of the southeast Arabain Sea and the equatorial Indian Ocean, with atmospheric heating predominantly attributed to BC (84 %) exhibiting highest atmospheric absorbing efficiency of 13.38. Our findings highlight the significant role of anthropogenic aerosols from south Asian outflow in shaping optical and radiative properties over the equatorial Indian Ocean and emphasize the need for further research to understand their broader climatic and environmental implications.

来源平台：ATMOSPHERIC ENVIRONMENT