Detection and reconnaissance of pollutant clouds by CO 2 lidar (MIRELA)

Abstract

To determine the presence of a pollutant cloud in the atmosphere, France and the United States have collaborated on the development of a DIAL (Differential Absorption LIDAR) and DISC (Differential Scattering) LIDAR. This system called MIRELA, is financed by the DGA (France) and ERDEC (USA). It was developed in cooperation with the CILAS company (France) and uses a frequency agile CO2 laser designed and manufactured by the Hughes Aircraft Company (USA).Before using a LIDAR for the remote detection of atmospheric pollutants, the optical characteristics of the products to be detected must be known. This basic characterization is used to define the parameters of the system and select the detection technologies and algorithms.A simulation with the HITRAN data base provides a set of expected measurements. Comparison with the real results is excellent.The tests were run on realistic clouds. The backscattered signal received from the aerosols at the front of the cloud was detected as well as the return from a target placed beyond the cloud thus a transmission measurement was taken simultaneously with the backscattering measurement. These measurements show that the backscattering signals are characteristic of the cloud and will be used to detect and identify the products.