Aerosol and Planetary-Boundary-Layer Interactions and Impact on Convection in Urban Regions

Abstract:

By reflecting and absorbing solar radiation and serving as the cloud condensation nuclei (CCN), aerosols can significantly impact the developments of the planetary-boundary-layer (PBL) and clouds. Aerosol-induced changes in the surface heat flux and atmospheric thermal structure affect the stability of the atmosphere, the initiation and evolution of convection and cumulus clouds. Together with the aerosol microphysical effects, they jointly influence cloud and precipitation and thunderstorms. The team has conducted comprehensive studies of integrated observation, data analysis, and model simulation concerning virtually all aspects of the aforementioned processes. More focus has been placed in major metropolitan regions in US and China where the impact is particularly strong. This talk intends to provide an overview of the pertinent studies with more details given by individual presentations to follow. It covers the following key themes but not exclusively to them.

(1) a novel approach of obtaining highly space-time-resolved boundary layer heights, by overcoming inherent limitations in the lidar remote sensing of the PBL;

(2) the relationship between aerosol characteristics, boundary layer height, and cloud coupling;

(3) the joint influences of aerosol and urbanization on the spatial contrast in urban regions;

(4) the impact of aerosol characteristics on clouds and rainfall under different meteorological regimes and environment.