Combined Raman-elastic backscatter lidar method for the measurement of backscatter ratios

A variation of the conventional combined Raman-elastic backscatter lidar method, the 1-2-3 lidar method, is described and analyzed. This method adds a second transmitter wavelength to the conventional combined Raman-elastic backscatter lidar. This transmitter wavelength is identical to that of the Raman receiver. One can generate the transmitted beam at this wavelength by Raman shifting the laser radiation in molecular nitrogen or oxygen. Measuring a second elastic lidar signal at the Raman-shifted wavelength makes it possible to eliminate differential transmission effects that can cause systematic errors in conventional combined Raman-elastic backscatter lidar.