Ground-based lidar study of aerosol and boundary layer characteristics during INDOEX first field phase

This paper presents the extensive observations of atmospheric aerosol vertical distributions that have been carried out during the first field phase (FFP) of the Indian Ocean experiment (INDOEX-FFP 98) using the computer-controlled Argon-ion lidar system at the Indian Institute of Tropical Meteorology (IITM), Pune, a tropical urban station in India. These observations primarily will help explaining the teleconnections between the inland aerosol characteristics, and the marine aerosol properties observed from the ORV Sagar Kanya cruise during the same period. Vertical profiles of night-time aerosol concentration up to about 7 km above ground level were obtained on 25 days during the INDOEX-FFP 98 (17 February-31 March 1998). These profiles have also been utilized to investigate the nocturnal structure and stratification of the planetary boundary layer and associated air quality. The aerosol vertical distributions and the associated aerosol columnar content show significant day-to-day variations, particularly in the nocturnal boundary layer (NBL) and exhibit increasing trend during the study period. The derived ventilation coefficients are found to associate more closely with wind speed as compared to mixing depth