Global parameterization and validation of a two‐leaf light use efficiency model for predicting gross primary production across FLUXNET sites

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• 作者：Yanlian Zhou ; Xiaocui Wu ; Weimin Ju ; Jing M. Chen ; Shaoqiang Wang ; Huimin Wang ; Wenping Yuan ; T. Andrew Black ; Rachhpal Jassal ; Andreas Ibrom ; et al
• 刊名：Journal of Geophysical Research: Biogeosciences
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：121
• 期：4
• 页码：1045-1072
• 全文大小：2.6MB
• ISSN：2169-8961

文摘

Light use efficiency (LUE) models are widely used to simulate gross primary production (GPP). However, the treatment of the plant canopy as a big leaf by these models can introduce large uncertainties in simulated GPP. Recently, a two-leaf light use efficiency (TL-LUE) model was developed to simulate GPP separately for sunlit and shaded leaves and has been shown to outperform the big-leaf MOD17 model at six FLUX sites in China. In this study we investigated the performance of the TL-LUE model for a wider range of biomes. For this we optimized the parameters and tested the TL-LUE model using data from 98 FLUXNET sites which are distributed across the globe. The results showed that the TL-LUE model performed in general better than the MOD17 model in simulating 8 day GPP. Optimized maximum light use efficiency of shaded leaves (ε_msh) was 2.63 to 4.59 times that of sunlit leaves (ε_msu). Generally, the relationships of ε_msh and ε_msu with ε_max were well described by linear equations, indicating the existence of general patterns across biomes. GPP simulated by the TL-LUE model was much less sensitive to biases in the photosynthetically active radiation (PAR) input than the MOD17 model. The results of this study suggest that the proposed TL-LUE model has the potential for simulating regional and global GPP of terrestrial ecosystems, and it is more robust with regard to usual biases in input data than existing approaches which neglect the bimodal within-canopy distribution of PAR.