COMPARISON OF CONTINUOUS-WAVE CO2 LIDAR CALIBRATION BY USE OF EARTH-SURFACE TARGETS IN LABORATORY AND AIRBORNE MEASUREMENTS

Backscatter of several Earth surfaces was characterized in the laborat ory as a function of incidence angle with a focused continuous-wave 9. 1-mu m CO2 Doppler lidar for use as possible calibration targets. Some targets showed negligible angular dependence, while others showed a s light increase with decreasing angle. The Earth-surface signal measure d over the complex Californian terrain during a 1995 NASA airborne mis sion compared well with laboratory data. Distributions of the Earth's surface signal shows that the lidar efficiency can be estimated with a fair degree of accuracy, preferably with uniform Earth-surface target s during flight for airborne or space-based lidar.