Real-time monitoring of atmospheric aerosols using a computer-controlled lidar

Regular monitoring of aerosol parameters during nighttime in the tropical urban lower atmosphere using a tunable, continuous wave, bistatic argon ion laser radar (lidar) system was initiated at the Indian Institute of Tropical Meteorology, Pune (18°32′N, 73°N51′E), India in 1986. So far, the measurements have been made from manual operation of the lidar which consumes a lot of time and inhibits interpretation of results immediately after completion of the experiment. In order to improve and expedite the data acquisition-processing and to avoid extra manual work to a considerable extent, the lidar has recently been made fully automatic. This paper discusses the on-line control and digital data system that provides real-time acquisition, analysis and display of lidar data. The improvements in the data quality and application of the system to the real-time observation of various features connected with atmospheric aerosol variations in both space and time are presented. The previously used lidar data acquisition and handling techniques and those of the present auto-mode operation are compared. Such real-time aerosol observations on a long-term basis are expected to lead to a better understanding of the optical properties of aerosols and their interaction with clouds and climate and will hopefully add to the global monitoring efforts and attempts at incorporating aerosols into climate models.