Sun-induced chlorophyll fluorescence (SIF) is a promising new tool for remotely estimating photosynthesis. However, the degree to which incoming solar radiation and the structure of the canopy rather than leaf physiology contribute to SIF variations is still not well characterized. Therefore, we investigated relationships between SIF and variables that at least partly capture the canopy structure component of SIF. For this, we relied on high-quality SIF observations from ground-based instruments, high-resolution airborne SIF imagery and the most recent satellite SIF products to cover large ranges in spatial and temporal resolution and diverse ecosystems. We found that the canopy structure-related near-infrared reflectance of vegetation multiplied by incoming sunlight (NIR_VP) is a robust proxy for far-red SIF across a wide range of spatial and temporal scales. Our findings indicate that contributions from leaf physiology to SIF variability are small compared to the structure and radiation components. Also, NIR_VP captured spatio-temporal patterns of canopy photosynthesis better than SIF, which seems to be mostly due to the greater retrieval noise of SIF. Compared to other relevant structural SIF proxies, NIR_VP showed more robust relationships to SIF, especially at the global scale. Our results highlight the promise of using widely available NIR_VP data for vegetation monitoring and also indicate the potential of using SIF and NIR_VP in combination to extract physiological information from SIF.

太阳诱导的叶绿素荧光 (SIF) 是一种很有前途的新工具，可用于远程估计光合作用。然而，入射太阳辐射和冠层结构而不是叶片生理对 SIF 变化的影响程度仍然没有得到很好的表征。因此，我们调查了 SIF 与至少部分捕获 SIF 冠层结构成分的变量之间的关系。为此，我们依靠来自地面仪器的高质量 SIF 观测、高分辨率机载 SIF 图像和最新的卫星 SIF 产品来覆盖大范围的时空分辨率和多样化的生态系统。我们发现植被的冠层结构相关的近红外反射率乘以入射阳光（NIR _VP) 是远红 SIF 在广泛的空间和时间尺度上的稳健代理。我们的研究结果表明，与结构和辐射成分相比，叶片生理学对 SIF 变异性的贡献很小。而且，NIR _V P捕获篷光合作用的时空图案比SIF，这似乎是主要是由于SIF中的较大者检索噪声更好。相对于其他相关的结构SIF代理，NIR _V P则为以SIF更强劲的关系，特别是在全球范围内。我们的结果强调了使用广泛可用的 NIR _V P 数据进行植被监测的前景，并表明结合使用 SIF 和 NIR _V P 从 SIF 中提取生理信息的潜力。