Range-Resolved Heterodyne Detection Dual CO2 DIAL Measurements

Abstract

There are a number of measurements of atmospheric trace species and aerosols of potential interest in the 9 to 11 micron spectral region covered by CO2 lasers. While direct detection CO2 lidar systems have been used for such range-resolved measurements, the measurement range for such systems is limited to 2 to 4 km (Flanigan, 1986). Heterodyne detection CO2 DIAL was proposed by Kobayasi and Inaba, 1975, and first realized by Fukuda et al., 1984 and Hardesty, 1984, using single laser lidar systems. Heterodyne detection offers increased range (to 10 km or more), but demands greater system and data analysis complexity. This paper will describe measurements made using the Mobile Atmospheric Pollutant Mapping System (MAPM).