A backscatter lidar observations of lower atmospheric aerosol during daytime over a tropical rural site Gadanki

摘要

An elastic backscattering lidar system that is capable of operating in daytime, which is considered to be first of its kind in India, has been developed at Gadanki (13.5° N, 79.2° E), a tropical rural site, to provide the vertical profile of the aerosol backscatter ratio at 532nm up to an altitude of 5-6 km (AGL). We made observations of the lower tropospheric aerosols during Dec 2002 - March 2003 with the system. The following observations are bought out from the preliminary analysis of the data, (a) A thick aerosol layer will always be present in the lowermost troposphere which top 1.5 - 2 km above the ground level. We consider that the layer correspond to the local mixing layer, (b) A thin layer of aerosol exists in the free troposphere in the altitude of 3 to 5 km. It is considered that these layers were on the way of long-range transport (c) A clear dust layer appeared at height of 2-3 km during the months Feb and March 2003. The lidar data has also used to retrieve the Convective Boundary Layer (CBL) height over the tropical site Gadanki.