Distortion of particulate extinction profiles measured with lidar in a two-component atmosphere

Abstract

Distortions of particular extinction-coefficient profiles measured with lidar in a two-component (molecular and aerosol) scattering atmosphere are analyzed. The error of the extinction coefficient measured at range r depends on the location of the point r(b), where a boundary value is specified, and the particulate optical depth of the atmosphere between r and r(b); the particulate backscatter-to-extinction ratio; and the ratio of particulate and molecular scattering extinction. If the near-end solution is used, small measurement errors can produce a significant divergence between the actual and the retrieved extinction-coefficient profiles, even if the boundary value and the particulate backscatter-to-extinction ratio are specified accurately. This effect is exacerbated at small values of the particulate scattering coefficient and the backscatter-to-extinction ratio. When reasonable criteria are used, feasible minimum and maximum boundary values can be specified to restrict the range of lidar equation solutions from below and from above.