HR: 0800h
AN: C21B-0471    [Abstracts]
TI: Comparison of Algorithms for Incoming Atmospheric Long-wave Radiation
AU: * Flerchinger, G N
EM: gflerchi@nwrc.ars.usda.gov
AF: USDA-ARS, 800 Park Blvd., Suite 105, Boise, ID 83712, United States
AU: Xaio, W
EM: xiaowei_522@163.com
AF: Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, No. 11A, Datun Road, Beijing, 100101, China
AU: Marks, D
EM: dmarks@nwrc.ars.usda.gov
AF: USDA-ARS, 800 Park Blvd., Suite 105, Boise, ID 83712, United States
AU: Sauer, T J
EM: sauer@nstl.gov
AF: USDA-ARS, 2150 Pammel Drive, Ames, IA 50011, United States
AU: Yu, Q
EM: yuq@igsnrr.ac.cn
AF: Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, No. 11A, Datun Road, Beijing, 100101, China
AB: Early season snowmelt can be dominated by the long-wave radiation balance. While numerous algorithms exist for predicting incident atmospheric long-wave radiation under clear (L_clr) and cloudy skies, only a handful comparisons have been published to assess the accuracy of the different algorithms. Virtually no comparisons have been made for both clear and cloudy skies across multiple sites. This study evaluates the accuracy of twelve algorithms for predicting incident long-wave radiation under clear skies, ten cloud correction algorithms, and four algorithms for all-sky conditions using data from twelve sites across North America and China. Data from three sites were combined with publicly available data from nine sites in the AmeriFlux network. Clear sky algorithms that excelled in predicting L_clr were the Dilley-O'Brien, Prata, and Angstrom algorithms. Root mean square difference (RMSD) between predicted and measured L_clr averaged 22 to 23 Wm^-2 for these three algorithms across all sites. Cloud-correction algorithms of Kimball, Unsworth-Monteith and Crawford described the data best when combined with the Dilley clear-sky algorithm. Average RMSD across all sites for these three cloud corrections was 24 Wm^-2. Based on the results, the recommended algorithms can be applied with reasonable accuracy for a wide range of climates, elevations and latitudes.
DE: 0764 Energy balance
DE: 0798 Modeling
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
DE: 3359 Radiative processes
SC: Cryosphere [C]
MN: 2007 Fall Meeting