Abstract 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 (Vcmax), which is determined by the leaf biochemistry and the environmental conditions. Vcmax 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 Vcmax effects on the canopy spectrum. This development provides an approach to retrieve Vcmax 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. Vcmax 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 Vcmax retrieved from model inversion were higher (r2 = 0.7–0.8) than when SIF was used alone (r2 = 0.5–0.6) or when traditional vegetation indices were used (r2 = 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 Vcmax derived using SCOPE (r2 = 0.56, p

中文翻译：

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用机载纳米高光谱成像仪对杏树中的同化率进行绿色光谱区域的物理模型反演

摘要 在过去的几十年中，光合作用活动的遥感取得了重大进展，包括传感器设计和辐射传递模型 (RTM) 的开发。然而，找到准确量化跨物种和空间尺度的碳同化的方法仍然是一个挑战。大多数方法要么是经验性的，不能跨尺度转移，要么只能在可以获得高度复杂的输入数据的情况下应用。在胁迫下，光合速率受到最大羧化速率 (Vcmax) 的限制，该速率由叶片生化和环境条件决定。Vcmax 与植物光保护机制、光合活性和叶绿素荧光发射有关。最近的 RTM 发展，例如光合作用和能量通量的土壤冠层观测 (SCOPE) 模型允许模拟太阳诱导的叶绿素荧光 (SIF) 和 Vcmax 对冠层光谱的影响。这一发展提供了一种通过 RTM 模型反演和轨道同化率来检索 Vcmax 的方法。在这项研究中，我们探索了 SIF、窄带指数和 RTM 反演，以跟踪作为植被压力函数的光合效率变化。我们使用在不同管理策略下在杏仁园上获得的高光谱图像，这些策略影响了实地测量的同化率。用作同化指标的 Vcmax 是通过 SCOPE 模型反演从纯树冠高光谱数据中得到的。与单独使用 SIF 时（r2 = 0.5-0.6）或使用传统植被指数时（r2 = 0.3-0.5）相比，现场测量的同化率与从模型反演中获得的 Vcmax 之间的关系更高（r2 = 0.7-0.8） . 当应用于在整个季节的两个不同日期获得的两个独立数据集时，该方法被证明是成功的，确保了其稳健性和可转移性。当同时应用于两个日期时，结果显示在田间测量的同化与使用 SCOPE 得出的 Vcmax 之间存在独特的显着趋势（r2 = 0.56，p 当应用于在整个季节的两个不同日期获得的两个独立数据集时，该方法被证明是成功的，确保了其稳健性和可转移性。当同时应用于两个日期时，结果显示在田间测量的同化与使用 SCOPE 得出的 Vcmax 之间存在独特的显着趋势（r2 = 0.56，p 当应用于在整个季节的两个不同日期获得的两个独立数据集时，该方法被证明是成功的，确保了其稳健性和可转移性。当同时应用于两个日期时，结果显示在田间测量的同化与使用 SCOPE 得出的 Vcmax 之间存在独特的显着趋势（r2 = 0.56，p