Spectral correlation of atmospheric lidar returns with range-dependent backscatter

Expressions are derived for the spectrum of atmospheric backscatter coherent lidar returns in the presence of arbitrary line-of-sight backscatter nonuniformities. It is shown that, in contrast to microwave weather radar, sample measurement spectra are smoothed, although mean spectra and therefore the first-order coherence of the return are unaffected. Simulated data are used to demonstrate that estimates of return power are degraded by sample smoothing, but some estimates of mean Doppler shift are improved.