Publications

Kant, S; Panda, J; Rath, SS (2025). Observational evidence of aerosol-warm cloud interaction over two urban locations in eastern India. FRONTIERS OF EARTH SCIENCE.

Abstract
Aerosol-cloud interaction remains challenging due to the large uncertainties caused by the associated meteorological effects. This study examines the aerosol-warm cloud interaction over the cities of Bhubaneswar and Rourkela. A negative cloud effective radius (CER)-cloud optical depth and CER-cloud top pressure (CTP) relationship is found in all the regimes of aerosol optical depth (AOD) over Bhubaneswar and Rourkela, excluding CER-CTP association in heavy pollution scenarios over Rourkela. However, a significant positive CER-cloud water path (CWP) correlation is observed in all the cases of AOD over both cities. This can be attributed to strong competition between aerosol and cloud droplets for water vapor association. CER is found to increase with AOD in all the regimes of relative humidity (RH) over both cities, excluding low and high cases of RH over Bhubaneswar. In this scenario, enhanced collision and coalescence efficiency and increased water vapor content encourage the merging of smaller droplets, resulting in the growth in effective radius of clouds. Negative pressure vertical velocity (PVV) over these cities infers that the upward movement of the air parcels helps in the growth of cloud droplets and aerosol particles besides enhancing the cloud cover. The shift from the Anti-Twomey effect to the Twomey effect has been noticed in both urban areas, with the Twomey effect being the major influence. Overall results indicated aerosol-induced heating may increase the response of turbulent heat flux (sensible heat over the land), leading to enhanced stability at the lower troposphere and subsequent suppression of vertical mixing. It results in moisture trapping near the surface and increases warm clouds in Rourkela. However, the predominance of a positive semi-direct effect over Bhubaneswar leads to an adverse relationship between warm cloud cover and aerosols.

DOI:
10.1007/s11707-024-1124-z

ISSN:
2095-0209