DOI: 10.1002/2017JG004370
Scopus记录号: 2-s2.0-85045526654
论文题名: An Evaluation of Semiempirical Models for Partitioning Photosynthetically Active Radiation Into Diffuse and Direct Beam Components
作者: Oliphant A.J. ; Stoy P.C.
刊名: Journal of Geophysical Research: Biogeosciences
ISSN: 21698953
出版年: 2018
卷: 123, 期: 3 起始页码: 889
结束页码: 901
语种: 英语
英文关键词: atmospheric scattering
; biometeorology
; diffuse PAR modeling
; micrometeorology
; photosynthetically active radiation
Scopus关键词: accuracy assessment
; data set
; diffusion
; empirical analysis
; micrometeorology
; model validation
; optimization
; photosynthesis
; photosynthetically active radiation
; scattering
; transparency
英文摘要: Photosynthesis is more efficient under diffuse than direct beam photosynthetically active radiation (PAR) per unit PAR, but diffuse PAR is infrequently measured at research sites. We examine four commonly used semiempirical models (Erbs et al., 1982, https://doi.org/10.1016/0038-092X(82)90302-4; Gu et al., 1999, https://doi.org/10.1029/1999JD901068; Roderick, 1999, https://doi.org/10.1016/S0168-1923(99)00028-3; Weiss & Norman, 1985, https://doi.org/10.1016/0168-1923(85)90020-6) that partition PAR into diffuse and direct beam components based on the negative relationship between atmospheric transparency and scattering of PAR. Radiation observations at 58 sites (140 site years) from the La Thuille FLUXNET data set were used for model validation and coefficient testing. All four models did a reasonable job of predicting the diffuse fraction of PAR (ϕ) at the 30 min timescale, with site median r2 values ranging between 0.85 and 0.87, model efficiency coefficients (MECs) between 0.62 and 0.69, and regression slopes within 10% of unity. Model residuals were not strongly correlated with astronomical or standard meteorological variables. We conclude that the Roderick (1999, https://doi.org/10.1016/S0168-1923(99)00028-3) and Gu et al. (1999, https://doi.org/10.1029/1999JD901068) models performed better overall than the two older models. Using the basic form of these models, the data set was used to find both individual site and universal model coefficients that optimized predictive accuracy. A new universal form of the model is presented in section 5 that increased site median MEC to 0.73. Site-specific model coefficients increased median MEC further to 0.78, indicating usefulness of local/regional training of coefficients to capture the local distributions of aerosols and cloud types. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/114368
Appears in Collections: 气候减缓与适应
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作者单位: Department of Geography & Environment, San Francisco State University, San Francisco, CA, United States; Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, United States
Recommended Citation:
Oliphant A.J.,Stoy P.C.. An Evaluation of Semiempirical Models for Partitioning Photosynthetically Active Radiation Into Diffuse and Direct Beam Components[J]. Journal of Geophysical Research: Biogeosciences,2018-01-01,123(3)