Show simple item record

contributor authorYang, Fanglin
contributor authorMitchell, Kenneth
contributor authorHou, Yu-Tai
contributor authorDai, Yongjiu
contributor authorZeng, Xubin
contributor authorWang, Zhuo
contributor authorLiang, Xin-Zhong
date accessioned2017-06-09T16:22:20Z
date available2017-06-09T16:22:20Z
date copyright2008/11/01
date issued2008
identifier issn1558-8424
identifier otherams-66646.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4208005
description abstractThis study examines the dependence of surface albedo on solar zenith angle (SZA) over snow-free land surfaces using the intensive observations of surface shortwave fluxes made by the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Program and the National Oceanic and Atmospheric Administration Surface Radiation Budget Network (SURFRAD) in 1997?2005. Results are used to evaluate the National Centers for Environmental Prediction (NCEP) Global Forecast Systems (GFS) parameterization and several new parameterizations derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) products. The influence of clouds on surface albedo and the albedo difference between morning and afternoon observations are also investigated. A new approach is taken to partition the observed upward flux so that the direct-beam and diffuse albedos can be separately computed. The study focused first on the ARM Southern Great Plains Central Facility site. It is found that the diffuse albedo prescribed in the NCEP GFS matched closely with the observations. The direct-beam albedo parameterized in the GFS is largely underestimated at all SZAs. The parameterizations derived from the MODIS product underestimated the direct-beam albedo at large SZAs and slightly overestimated it at small SZAs. Similar results are obtained from the analyses of observations at other stations. It is also found that the morning and afternoon dependencies of direct-beam albedo on SZA differ among the stations. Attempts are made to improve numerical model algorithms that parameterize the direct-beam albedo as a product of the direct-beam albedo at SZA = 60° (or the diffuse albedo), which varies with surface type or geographical location and/or season, and a function that depends only on SZA. A method is presented for computing the direct-beam albedos over these snow-free land points without referring to a particular land-cover classification scheme, which often differs from model to model.
publisherAmerican Meteorological Society
titleDependence of Land Surface Albedo on Solar Zenith Angle: Observations and Model Parameterization
typeJournal Paper
journal volume47
journal issue11
journal titleJournal of Applied Meteorology and Climatology
identifier doi10.1175/2008JAMC1843.1
journal fristpage2963
journal lastpage2982
treeJournal of Applied Meteorology and Climatology:;2008:;volume( 047 ):;issue: 011
contenttypeFulltext


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record