Doppler spectral scanning differential absorption lidar

Preliminary experiments toward the implementation of Doppler spectral scanning differential absorption lidar (DSS DIAL) are described. In separate tests, CO2 laser pulses were reflected from either a ground-based retroreflector (36-km round-trip distance) or a retroreflector on the GEOS-3 satellite (approximately 2000-km round-trip distance). The returns were split into a reference channel and an absorptive gas-cell channel. The light was coherently detected with heterodyne receivers and analyzed. Results from the ground-based system produced data that matched expected values in one case but its repeatability remains to be determined. We are currently investigating the satellite-based system to assess the DSS DIAL technique.