High-Cloud Horizontal Inhomogeneity and Solar Albedo Bias

Journal Article · Sun Sep 01 04:00:00 EDT 2002 · Journal of Climate, 15(17):2321-2339

DOI:https://doi.org/10.1175/1520-0442(2002)015<2321:HCHIAS>2.0.CO;2· OSTI ID:15001746

Carlin, Betty; Fu, Qiang; Lohmann, Ulrike; Mace, Gerald G; Sassen, K; Comstock, Jennifer M

High ice cloud horizontal inhomogeneity is examined using optical depth retrievals from four midlatitude datasets. Three datasets include ice cloud microphysical profiles derived from millimeter cloud radar at the Southern Great Plains Atmospheric Radiation Measurement site in Oklahoma. A fourth dataset combines lidar and midinfrared (LIRAD), and is from the Facility for Atmospheric Remote Sensing at the University of Utah, Salt Lake City, Utah. Plane-parallel homogeneous (PPH) calculations of domain-averaged solar albedo for these four datasets are compared to independent column approximation (ICA) results. A solar albedo bias up to 25% is found over a low reflective surface at a high solar zenith angle. A spherical solar albedo bias as high as 11% is shown. The gamma-weighted radiative transfer (GWRT) scheme is shown to be an effective correction for the solar albedo bias suitable for GCM applications. The GWRT result was, in all cases, within 1-2 W m-2 of the ICA outgoing solar flux. The GWRT requires a parameterization of the standard deviation of cloud optical depth. It is suggested that the domain-averaged cloud optical depth and ice water path together can be used in a parameterization to account for 80% of the standard deviation in optical depth.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 15001746
• Report Number(s): PNNL-SA-37198; KP1201030
• Journal Information: Journal of Climate, 15(17):2321-2339, Journal Name: Journal of Climate, 15(17):2321-2339
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES