Vertical distribution of aerosols over an urban continental site in India inferred using a micro pulse lidar

Abstract

Knowledge of the vertical distribution of aerosols in the atmosphere is important in estimating its radiative forcing. While aircraft based measurements over two locations in India have provided valuable information, the temporal coverage of measurements was limited. In this paper, we examine the vertical distribution of aerosols over a continental, urban location, Bangalore in southern India, using a micro pulse lidar (MPL) operated for about two years (2004 and 2005), and infer the effects of the boundary layer dynamics. Early morning hours are characterized by a shallow aerosol layer, a few hundred meters thick. As day advances, the strong convective eddies are seen to transport the aerosols vertically up to more than 1500 m. Seasonal changes in the aerosol vertical structure, contribution of the boundary layer aerosols to the column optical depth as well as the frequency of occurrence of clouds within aerosol layer are examined.