This paper presents a new approach to estimate spatial Sun-Induced Fluorescence (SIF) using the empirical relationship between simulated Canopy Chlorophyll Concentration (CCC) and simulated SIF. PROSAIL model [PROpriétésSPECTrales (PROSPECT) and Scattering by Arbitrarily Inclined Leaves (SAIL) models] was used to simulate CCC. CCC maps were generated through an Automated Radiative Transfer Model Operator (ARTMO) using the PROSAIL model and Sentinel-2 Multi-Spectral Imager (MSI) imagery. The Soil Canopy Observation, Photochemistry, and Energy fluxes (SCOPE) model was used to simulate SIF emitted at 740 nm (SIF₇₄₀), at 760 nm (SIF₇₆₀), and top of canopy (SIF_TOC) (640-850 nm). The SCOPE model, configured with the specification of the Sentinel-2 sensor, simulates SIF within the spectrum range of 640-850 nm. A non-linear logarithmic relationship (R²>0.9, p < 0.05) was observed between simulated SIF and simulated CCC. Simulated CCC was linearly related to observed CCC with R² 0.88, 0.92 and 0.89 and RMSE = 0.04, 0.17 and 0.09 gm/m² at p < 0.05 for summer, post-monsoon and early winter respectively. Whereas, the simulated CCC did not capture the full range of CCC variability for the post-monsoon season. Simulated SIF (SIF₇₆₀) was well correlated with SIF from Orbiting Carbon Observatory-2 (OCO-2) satellite with R² 0.68, 0.73 and 0.73 (RMSE = <1 W/m²/sr/μm, p < 0.05) for the month of summer (April), pre-monsoon (May) and early winter season (November) respectively. Temporal SIF_TOC effectively captured the seasonal variability associated with the phenology of deciduous tree species. Among various Sentinel-2 MSI derived VIs, Red Edge NDVI (RENDVI) exhibited maximum sensitivity with SIF (highest monthly average R²> 0.6, p < 0.05). The spatial SIF would serve as an useful link between airborne /satellite derived SIF and in-situ fluorescence measurements to understand multiscale SIF variability of terrestrial vegetation.

本文提出了一种利用模拟冠层叶绿素浓度（CCC）和模拟SIF之间的经验关系估计空间太阳诱导荧光（SIF）的新方法。使用PROSAIL模型[PROPRIétésSPECTrales（PROSPECT）和任意倾斜叶片散射（SAIL）模型]来模拟CCC。通过使用PROSAIL模型和Sentinel-2多光谱成像仪（MSI）图像的自动辐射转移模型算子（ARTMO）生成了CCC图。土壤冠层观测，光化学和能量通量（SCOPE）模型用于模拟在740 nm（SIF ₇₄₀），760 nm（SIF ₇₆₀）和树冠顶部（SIF _TOC）发射的SIF）（640-850 nm）。配置了Sentinel-2传感器规格的SCOPE模型可以模拟640-850 nm光谱范围内的SIF。在模拟SIF和模拟CCC之间观察到非线性对数关系（R ² > 0.9，p <0.05）。模拟的CCC与观测到的CCC呈线性相关，在夏季，季风后和初冬时，p <0.05的R ^2分别为R ² 0.88、0.92和0.89，RMSE = 0.04、0.17和0.09 gm / m ²。而模拟的CCC并没有捕获季风后季节CCC变异的全部范围。模拟的SIF（SIF ₇₆₀）与来自R ^2的轨道碳观测站2（OCO-2）卫星的SIF很好地相关夏季（4月），季风前（5月）和初冬（11月）分别为0.68、0.73和0.73（RMSE = <1 W / m ² / sr /μm，p <0.05）。时间SIF _TOC有效地捕获了与落叶树种物候相关的季节性变化。在各种Sentinel-2 MSI衍生的VI中，Red Edge NDVI（RENDVI）表现出SIF的最高灵敏度（最高每月平均R ² > 0.6，p <0.05）。空间SIF将作为机载/卫星衍生SIF与原位荧光测量之间的有用链接，以了解陆地植被的多尺度SIF变异性。