Some Aspects of Rayleigh and Mie Scattering in the Atmosphere Over Pune

Abstract

Computations of aerosol mixing ratio [( Na + Nm)/Nm] have been made using the aerosol number density (Na) estimated from the laser radar (lidar) observations carried out at the IITM, Pune and air molecular number density (Nm) derived from the radiomatersonde data of temperature and pressure obtained from the IMD, Pune for the days of lidar observations. The results of the study of the seasonal variation in the vertical distribution (up to 5 km AGL) of aerosol mixing ratio (AMR) obtained from the above observations collected for the twp-year period, October 1986 - September 1988 are presented in this paper. The results indicate low AMR during the monsoon and high duirng the winter months. These variations noticed for the monsoon and winter seasons are considered to be mainly due to the differences in Na. This is consistent with the seasonal variation in the average profiles of aerosols and air molecules, which suggested an increase of about 50% in the case of aerosols and about 2% in the case of air molecules during the winter season as compared to those observed duirng the monsoon season.