Information Content of AVHRR Channels 4 and 5 with Respect to the Effective Radius of Cirrus Cloud Particles

• DOI: 10.1175/1520-0450-30.7.973
• Publication Date: 2010-08-07T11:44:42Z
• Authors: F. Parol; J. C. Buriez; G. Brogniez; Y. Fouquart
• Keywords: Effective radius; Cirrus; Supercooling

Abstract This paper investigates the important difference in relationship between brightness temperatures 11-μm and 12-μn AVHRR data microphysical properties of semitransparent cirrus clouds. In nonscattering approximation, emittance for channels 4 5 are related through absorption coefficient ratio that is key parameter giving access to size cloud particles. The observed mean value this corresponds effective radius 18 μm polydisperse spheres 12 infinitely long ice cylinders. Taking multiple scattering into account, temperature enhances much more cylinders than owing fact forward peak less large To obtain particles, method developed case still applicable if one makes use implicitly includes effects mattering. Thus, an defined we derive a direct optical 26 or bit water (supercooled droplets), but no agreement can be obtained fully randomly oriented