Open AccessEmpirical model of multiple-scattering effect on single-wavelength lidar data of aerosols and clouds
Author(s) -
Valéry Shcherbakov,
Frédéric Szczap,
Alaa Alkasem,
Guillaume Mioche,
Céline Cornet
Publication year - 2022
Publication title -
atmospheric measurement techniques
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.679
H-Index - 88
eISSN - 1867-8548
pISSN - 1867-1381
DOI - 10.5194/amt-15-1729-2022
Subject(s) - lidar , scattering , cirrus , aerosol , extinction (optical mineralogy) , monte carlo method , wavelength , environmental science , computational physics , remote sensing , optics , forward scatter , physics , materials science , meteorology , geology , mathematics , statistics
. We performed extensive Monte Carlo (MC) simulations ofsingle-wavelength lidar signals from a plane-parallel homogeneous layer ofatmospheric particles and developed an empirical model to account for themultiple scattering in the lidar signals. The simulations have taken intoconsideration four types of lidar configurations (the ground based, theairborne, the CALIOP, and the ATLID) and four types of particles (coarseaerosol, water cloud, jet-stream cirrus, and cirrus). Most of the simulationswere performed with a spatial resolution 20 m and particle extinction coefficients εp between 0.06 and 1.0 km−1. The resolution was 5 m for high values of εp (up to 10.0 km−1). The majority of simulations for ground-based and airborne lidars were performed at two values of the receiver field of view (RFOV): 0.25 and 1.0 mrad. The effect of the width of the RFOV was studied for values up to 50 mrad. The proposed empirical model is a function that has only three freeparameters and approximates the multiple-scattering relative contribution to lidar signals. It is demonstrated that the empirical model has very goodquality of MC data fitting for all considered cases. Special attention was given to the usual operational conditions, i.e. lowdistances to a layer of partices, small optical depths, and quite narrowreceiver fields of view. It is demonstrated that multiple-scattering effects cannot be neglected when the distance to a layer of particles is about 8 km or higher, and the full RFOV is 1.0 mrad. As for the full RFOV of 0.25 mrad, the single-scattering approximation is acceptable; i.e. the multiple-scattering contribution to the lidar signal is lower than 5 % for aerosols (εp≲1.0 km−1), water clouds (εp≲0.5 km−1), and cirrus clouds (εp≤0.1 km−1). When the distance to a layer of particles is 1 km, the single-scattering approximation is acceptable for aerosols and water clouds (εp≲1.0 km−1, both RFOV = 0.25 and RFOV = 1 mrad). As for cirrus clouds, the effect of multiplescattering cannot be neglected even at such low distances when εp≳0.5 km−1.