Assessment of the vertical distribution of speciated aerosol absorption over South Asia using spaceborne LIDAR and ground-based observations

Present study estimates the shortwave radiative effects of absorbing aerosols (dust and carbonaceous aerosols) over the Indian landmass using a synergy of spaceborne and ground-based observations. Vertical profiles of dust and total aerosols are estimated using the multi-year (2006-2017) observations from CALIOP (Cloud Aerosol Lidar with Orthogonal Polarization) over the Indian region. Pre-monsoon enhancement (March - -May) in aerosol loading over the Indian region is significantly contributed (similar to 56%) by the transported mineral dust at free tropospheric altitudes. Though, shortwave radiative effect due to dust in the atmosphere increases about three times from winter to pre-monsoon, at the top of the atmosphere (TOA) it causes cooling. Dust induced cooling reverses the positive radiative effect induced by non-dust aerosols at TOA over Indo-Gangetic Plains. Though the natural dust dominates the aerosol loading during pre-monsoon, anthropogenic dust contributes significantly (similar to 65%) to the total dust loading during winter. Over Indo-Gangetic Plains, high aerosol warming (up to similar to 2 Kday(-1)) observed within the planetary boundary layer (PBL) is mainly caused by carbonaceous aerosols (85%). The observed heating rates over the Indian region can have significant implications over regional climate, air quality, and changing precipitation patterns.

Automated summary

This study estimated the shortwave radiative effects of absorbing aerosols over the Indian landmass using a combination of spaceborne and ground-based observations, finding that pre-monsoon aerosol loading is mainly influenced by mineral dust and high aerosol warming within the planetary boundary layer is mainly caused by carbonaceous aerosols.