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| 作者 | Liu Min
; He Hong Lin
; Yu Gui Rui
; Luo Yi Qi
; Sun Xiao Min
; Wang Hui Min
|
| 发表日期 | 2009
|
| 关键词 | Curve fitting
Ecology
Fluxes
Least squares approximations
Maximum likelihood
Maximum likelihood estimation
Normal distribution
Optimization
Parameter estimation
Structural optimization
Tropics
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| 英文摘要 | We present an uncertainty analysis of ecological process parameters and CO2 flux components (Reco, NEE and gross ecosystem exchange (GEE)) derived from 3 years' continuous eddy covariance measurements of CO2 fluxes at subtropical evergreen coniferous plantation, Qianyanzhou of ChinaFlux. Daily-differencing approach was used to analyze the random error of CO2 fluxes measurements and bootstrapping method was used to quantify the uncertainties of three CO2 flux components. In addition, we evaluated different models and optimization methods in influencing estimation of key parameters and CO2 flux components. The results show that: (1) Random flux error more closely follows a double-exponential (Laplace), rather than a normal (Gaussian) distribution. (2) Different optimization methods result in different estimates of model parameters. Uncertainties of parameters estimated by the maximum likelihood estimation (MLE) are lower than those derived from ordinary least square method (OLS). (3) The differences between simulated Reco, NEE and GEE derived from MLE and those derived from OLS are 12.18% (176 g C · m-2 · a-1), 34.33% (79 g C · m-2 · a-1) and 5.4% (92 g C · m-2 · a-1). However, for a given parameter optimization method, a temperature-dependent model (T_model) and the models derived from a temperature and water-dependent model (TW_model) are 1.31% (17.8 g C · m-2 · a-1), 2.1% (5.7 g C · m-2 · a-1), and 0.26% (4.3 g C · m-2 · a-1), respectively, which suggested that the optimization methods are more important than the ecological models in influencing uncertainty in estimated carbon fluxes. (4) The relative uncertainty of CO2 flux derived from OLS is higher than that from MLE, and the uncertainty is related to timescale, that is, the larger the timescale, the smaller the uncertainty. The relative uncertainties of Reco, NEE and GEE are 4%-8%, 7%-22% and 2%-4% respectively at annual timescale. © Science in China Press and Springer-Verlag GmbH 2009. |
| 出处 | Science in China, Series D: Earth Sciences
 |
| 卷 | 52期:2页:257-268 |
| 收录类别 | EI
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| 语种 | 英语
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| 源URL | [http://ir.igsnrr.ac.cn/handle/311030/24745]  |
| 专题 | 地理科学与资源研究所_历年回溯文献
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推荐引用方式
GB/T 7714 |
Liu Min,He Hong Lin,Yu Gui Rui,et al. Uncertainty analysis of CO2 flux components in subtropical evergreen coniferous plantation. 2009.
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