Aerosol size distribution and refractive index from bistatic lidar angular scattering measurements in the surface layer

The results of an inversion method by iteration for determining the aerosol size distribution and the refractive index of atmospheric aerosols in the surface layer from bistatic lidar angular scattering measurements, followed by a brief description of the experimental and data retrieval techniques are presented. The continuous wave, bistatic Argon ion lidar at the Indian Institute of Tropical Meteorology (IITM), Pune (18° 32′N, 73°51′E, 559 m AMSL), India has been used for the measurements. Results of the analysis of 420 samples collected over a 7 yearsʹ period indicate mean value of size and refractive indices of 4.0 and 1.6, respectively, with greater fraction of larger particles during premonsoon while smaller particles during post-monsoon months at the lidar site. The retrieved aerosol parameters are compared with those determined from spectroradiometer observations at the same site. The results are found well in agreement with those obtained previously by the authors using the library search method. The above observations of angular distribution of scattered intensity are used with an aerosol model to infer the dominant type of aerosols present in the environment in and around the experimental station.