Effects of cirrus heterogeneity on lidar CALIOP/CALIPSO data. (November 2017)

• Record Type: Journal Article
• Authors: Alkasem, A.; Szczap, F.; Cornet, C.; Shcherbakov, V.; Gour, Y.; Jourdan, O.; Labonnote, L.C.; Mioche, G.
• Is Part Of: Journal of quantitative spectroscopy & radiative transfer. Volume 202(2017)
• Page Start: 38
• Page End: 49
• Publication Date: 2017-11
• Subjects: Radiative transfer -- Heterogeneous clouds -- Cirrus -- Lidar -- Backscatter -- Polarization; Spectrum analysis -- Periodicals; Radiation -- Periodicals; Analyse spectrale -- Périodiques; Rayonnement -- Périodiques; Radiation; Spectrum analysis; Periodicals; 543.0858
• DOI: 10.1016/j.jqsrt.2017.07.005
• Languages: English
• ISSNs: 0022-4073

Abstract

Highlights: Heterogeneous cirrus clouds are generated. Lidar signals are simulated using a Monte-Carlo code. Effects on CALIOP lidar measured data are evaluated. Importance of horizontal photon transport is underscored. Abstract: The goal of this work is to evaluate the effects of cirrus heterogeneity on characteristics that are directly measured by the CALIOP/CALIPSO lidar, i.e. attenuated backscatter coefficient and depolarization ratio. This assessment was done using the 3D Monte Carlo simulator of Polarized Lidar signals (3DMcPOLID) together with the high-resolution 3D cloud fields-generator 3DCLOUD_V2. The evaluation is based on random sampling and on comparison between mean profiles of 3D clouds and of plane-parallel equivalent 1D clouds. Mean profiles of the apparent attenuated backscatter as well as of the integrated apparent backscatter are statistically equal when a cirrus cloud field is probed with the 325 m resolution. To the contrary, the difference between profiles is statistically significant in the case of the 1 km resolution. Profiles of the volume depolarization ratio are statistically different for both cases of the horizontal resolution. The total bias of CALIOP/CALIPSO lidar data is mainly due to the plane parallel bias and multiple scattering, i.e., horizontal photon transport.