1. Remote Sensing Inversion of Leaf Maximum Carboxylation Rate Based on a Mechanistic Photosynthetic Model
- Author
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Wenyi Fan, Xiguang Yang, and Ying Yu
- Subjects
Coefficient of determination ,Carboxylation ,Photosynthetically active radiation ,General Earth and Planetary Sciences ,Environmental science ,Primary production ,Vegetation ,Electrical and Electronic Engineering ,Photochemical Reflectance Index ,Atmospheric sciences ,Photosynthesis ,Spatial distribution - Abstract
The maximum carboxylation rate (Vcmax) of a leaf is a rate-limiting step in photosynthesis. A quantitative spatial distribution of Vcmax is necessary to predictively understand forest gross primary production (GPP). In this study, we propose a new method that combines hyperspectral data with the Farquhar photosynthetic mechanistic model to estimate Vcmax. First, the photochemical reflectance index (PRI) of a leaf was calculated, and then a model of PRI and sunlit leaf light-use efficiency (LUE) was constructed to estimate sunlit leaf LUE. Next, sunlit leaf LUE and absorbed photosynthetically active radiation (APAR) were used to estimate the GPP of the sunlit leaf. Finally, Vcmax was deduced based on the Farquhar mechanistic model by using the GPP of sunlit leaves, and differences in Vcmax were analyzed across various types of vegetation. The results showed that the coefficient of determination between Vcmax estimated using the mechanistic model and the mean Vcmax measured at the sampling sites was 0.82, with a root mean square error of 4.27μmol·m⁻²·s⁻¹. Using a forest-type map of the Mao'er Mountain region as a reference, statistical analysis showed that coniferous forest showed the highest Vcmax, followed by coniferous-broadleaf mixed forest, while broad-leaved forest showed the lowest Vcmax. The proposed method can generate regional Vcmax distribution maps efficiently.
- Published
- 2022