Multi-Year CALIPSO Observations of Ubiquitous Elevated Aerosol Layer in the Free Troposphere Over South Asia: Sources and Formation Mechanism
Earth and Space Sciences
Aerosols distributed in the troposphere can scatter and absorb solar radiation and modify the Earth's radiation budget and cloud properties. The combined effect of scattering and absorption by particles is defined as aerosol extinction coefficient, is a measure of the alteration of radiant energy as it passes through the atmosphere. The aerosol extinction coefficient was derived with the space-borne lidar Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) over the Indian region during 2008–2018. The vertical profiles of aerosol extinction coefficient depicted persistent layers between 4 and 6 km over the Indian region named elevated aerosol layers (EALs). In the summer and fall seasons, the thickness of the EALs increased by 36.7% and 25% from the annual mean, respectively. Throughout the year, dust and polluted dust aerosols accounted for up to 50%–80% of the EALs composition between near-surface and 6 km. Stratified EALs between 4 and 6 km were formed by locally confined wind recirculation coupled with stable atmospheric layers during the winter, spring, and fall seasons. In summer, the vertical transport of pollutants from the planetary boundary layer to the mid-troposphere associated with enhanced deep convection played a crucial role in the formation of EALs
Kumar, G., Madhavan, B. L., Sahu, L. K., Kumar, Y. B., Vernier, J.-P.,Liu, H., et al. (2023). Multi-year CALIPSO observations of ubiquitous elevated aerosol layer in the free troposphere over South Asia: Sources and formation mechanism. Journal of Geophysical Research: Atmospheres, 128, e2021JD036277. https://doi.org/10.1029/2021JD036277
