Abstract

The objective of the JPL Lidar Target Calibration Facility is to provide accurate and consistent calibration of infrared lidar targets. Several CO₂ lidar systems are in use or planned, and these will contribute to an improved understanding of the global climatology of aerosol backscatter coefficients in the 9-11 μm region. Since quantitative values of the backscatter coefficient are desired, a technique for accurately calibrating the atmospheric backscatter data is necessary. The use of the total backscatter to Rayleigh backscatter ratio technique, which is often used in the visible to calibrate lidar responsivity, does not apply at mid-infrared wavelengths. Thus the lidar responsivity must be determined either by a careful, systematic measurement of the optical and quantum efficiencies of the optical and detector elements in the lidar and the far-field spatial patterns of the transmitter beam and receiver field-of-view, or by the use of a calibrated hard target which can be placed in the field at a suitable range or series of ranges. Even when the former technique is employed, the use of the hard target measurement is desirable as a cross-check.

© 1987 Optical Society of America