Modeling of light scattering in cirrus clouds with inhomogeneous hexagonal monocrystals. Comparison with in-situ and ADEOS-POLDER measurements

• Published in: Geophysical research letters Vol. 27; no. 1; pp. 113 - 116
• Main Authors: C. -Labonnote, Laurent, Brogniez, Gérard, Doutriaux-Boucher, Marie, Buriez, Jean-Claude, Gayet, Jean-François, Chepfer, Hélène
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 01.01.2000; American Geophysical Union
• Subjects: Atmospheric and Oceanic Physics; Cloud physics; Earth, ocean, space; Exact sciences and technology; External geophysics; Meteorology; Physics; France; Europe; Monte Carlo method; Light scattering; Mie scattering; Single crystal; Ice cloud; Measurement in situ; Nephelometry; Phase function; Ice crystals; Albedo; Hexagonal crystals; Cloud physics; Cirrus; Aircraft observation; Ray tracing; Radiometry; Numerical simulation; Air bubble; Reflectance
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/1999GL010839

An Inhhomogeneous Hexagonal Monocrystal (IHM) model is used to simulate light scattering by randomly oriented hexagonal ice crystals containing air bubbles. This model based on a combination of ray‐tracing, Mie theory and Monte‐Carlo techniques, allows to retrieve the scattering phase function. In‐situ measurements of the light scattering diagram in natural cirrus clouds with an airborne nephelometer have been performed. The results given by the IHM model have been favorably adjusted with these measurements. This agreement provides an opportunity to use this model in order to analyze ADEOS‐POLDER reflectance measurements over cirrus clouds. POLDER uses an original concept to measure, for a given scene, total and polarized reflectances under several viewing directions. A first analysis of cirrus cloud spherical albedoes for the 10th November 1996 shows a rather good agreement between measurements and calculations.