title: Comment on "Heterodyne lidar returns in the turbulent atmosphere: performance evaluation of simulated systems".
abstract: The explanation proposed by Belmonte and Rye [Appl. Opt. 39, 2401 (2000)] for the difference between simulation and the zero-order theory for heterodyne lidar returns in a turbulent atmosphere is incorrect. The theoretical expansion the authors considered is not developed under a square-law structure-function approximation (random-wedge atmosphere). Agreement between the simulations and the zero-order term of the theoretical expansion is produced for the limit of statistically independent paths (bistatic operation with large transmitter-receiver separation) when the simulations correctly include the large-scale gradients of the turbulent atmosphere.
authors.affiliation: Cooperative Institute for Research in Environmental Sciences, Campus Box 216, University of Colorado, Boulder, Colorado 80309, USA. rgf@cires.colorado.edu
authors.forename: Rod
authors.initials: R
authors.lastname: Frehlich
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kavaya