Physical model inversion of the green spectral region to track assimilation rate in almond trees with an airborne nano-hyperspectral imager

REMOTE SENSING OF ENVIRONMENT

卷:252

Article

Suarez, L.¹  Gonzalez-Dugo, V.²  Camino, C.³  Hornero, A.^2,4  Zarco-Tejada, P. J.^1,2 

[1] Univ Melbourne, Melbourne Sch Engn MSE, Dept Infrastruct Engn, Sch Agr & Food,Fac Vet & Agr Sci FVAS, Melbourne, Vic, Australia

[2] CSIC, Inst Agr Sostenible IAS, Ave Menendez Pidal S-N, Cordoba 14004, Spain

[3] European Commiss EC, Joint Res Ctr JRC, Ispra, VA, Italy

[4] Swansea Univ, Dept Geog, Swansea SA2 8PP, W Glam, Wales

关键词: Assimilation;    Photosynthesis;    Hyperspectral;    Radiative transfer model;    RTM;    SCOPE;    Vc(max);    Green spectral region;    Fluorescence;    SIF;    PRI;    Nano-Hyperspec;   

DOI  :  10.1016/j.rse.2020.112147

来源: Elsevier

【 摘 要 】

Significant advances toward the remote sensing of photosynthetic activity have been achieved in the last decades, including sensor design and radiative transfer model (RTM) development. Nevertheless, finding methods to accurately quantify carbon assimilation across species and spatial scales remains a challenge. Most methods are either empirical and not transferable across scales or can only be applied if highly complex input data are available. Under stress, the photosynthetic rate is limited by the maximum carboxylation rate (V-cmax), which is determined by the leaf biochemistry and the environmental conditions. V-cmax has been connected to plant photoprotective mechanisms, photosynthetic activity and chlorophyll fluorescence emission. Recent RTM developments such as the Soil-Canopy Observation of Photosynthesis and Energy fluxes (SCOPE) model allow the simulation of the sun-induced chlorophyll fluorescence (SIF) and V-cmax effects on the canopy spectrum. This development provides an approach to retrieve V-cmax through RTM model inversion and track assimilation rate. In this study we explore SIF, narrow-band indices and RTM inversion to track changes in photosynthetic efficiency as a function of vegetation stress. We use hyperspectral imagery acquired over an almond orchard under different management strategies which affected the assimilation rates measured in the field. V-cmax used as an indicator of assimilation was retrieved through SCOPE model inversion from pure-tree crown hyperspectral data. The relationships between field-measured assimilation rates and V-cmax retrieved from model inversion were higher (r(2) = 0.7-0.8) than when SIF was used alone (r(2) = 0.5-0.6) or when traditional vegetation indices were used (r(2) = 0.3-0.5). The method was proved successful when applied to two independent datasets acquired at two different dates throughout the season, ensuring its robustness and transferability. When applied to both dates simultaneously, the results showed a unique significant trend between the assimilation measured in the field and V-cmax derived using SCOPE (r(2) = 0.56, p < 0.001). This work demonstrates that tracking assimilation in almond trees is feasible using hyperspectral imagery linked to radiative transfer-photosynthesis models.

【 授权许可】

Free