An accurate parameterization of the infrared radiative properties of cirrus clouds for climate models

Journal Article · Tue Sep 01 04:00:00 EDT 1998 · Journal of Climate

DOI:https://doi.org/10.1175/1520-0442(1998)011<2223:AAPOTI>2.0.CO;2· OSTI ID:659001

Fu, Q; Sun, W B ^[1]; Yang, P ^[2]

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1. Dalhousie Univ., Halifax, Nova Scotia (Canada)
2. Univ. of Utah, Salt Lake City, UT (United States). Dept. of Meteorology/CARSS

An accurate parameterization is presented for the infrared radiative properties of cirrus clouds. For the single-scattering calculations, a composite scheme is developed for randomly oriented hexagonal ice crystals by comparing results from Mie theory, anomalous diffraction theory (ADT), the geometric optics method (GOM), and the finite-difference time domain technique. This scheme employs a linear combination of single-scattering properties from the Mie theory, ADT, and GOM, which is accurate for a wide range of size parameters. Following the approach of Q. Fu, the extinction coefficient, absorption coefficient, and asymmetry factor are parameterized as functions of the cloud ice water content and generalized effective size (D{sub ge}). The present parameterization of the single-scattering properties of cirrus clouds is validated by examining the bulk radiative properties for a wide range of atmospheric conditions. Compared with reference results, the typical relative error in emissivity due to the parameterization is {approximately}2.2%. The accuracy of this parameterization guarantees its reliability in applications to climate models. The present parameterization complements the scheme for the solar radiative properties of cirrus clouds developed by Q. Fu for use in numerical models.

• OSTI ID: 659001
• Journal Information: Journal of Climate, Journal Name: Journal of Climate Journal Issue: 9 Vol. 11; ISSN JLCLEL; ISSN 0894-8755
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CLIMATE MODELS
CLIMATIC CHANGE
CLOUDS
FORECASTING
INFRARED RADIATION