Solar glint from oriented crystals in cirrus clouds.
Solar scattering on oriented cirrus crystals near the specular reflection direction is modeled using a mix method combining geometric optics and diffraction effects at three wavelengths in the visible and infrared domains. Different potential sources of phase function broadening around the specular direction, such as multiple scattering, solar disk, or tilt effects, are studied by means of a Monte Carlo method. The radiance detected by an airborne sensor located a few kilometers above the cirrus cloud and pointing in the specular scattering direction is calculated at four solar zenith angles showing a dramatic increase of the signal in relation to the usual assumption of random crystal orientation.
Lavigne
Claire
C
Applied and Theoretical Optics Department, Office National d'Etudes et de Recherches Aérospatiales, The French Aerospace Lab, Chemin de la Hunière, 91761 Palaiseau Cedex, France. claire.lavigne@onera.fr
Roblin
Antoine
A
Chervet
Patrick
P