The need for progress in satellite remote sensing of terrestrial ecosystems is intensifying under climate change. Further progress in Earth observations of photosynthetic activity and primary production from local to global scales is fundamental to the analysis of the current status and changes in the photosynthetic productivity of terrestrial ecosystems. In this paper, we review plant ecophysiological processes affecting optical properties of the forest canopy which can be measured with optical remote sensing by Earth-observation satellites. Spectral reflectance measured by optical remote sensing is utilized to estimate the temporal and spatial variations in the canopy structure and primary productivity. Optical information reflects the physical characteristics of the targeted vegetation; to use this information efficiently, mechanistic understanding of the basic consequences of plant ecophysiological and optical properties is essential over broad scales, from single leaf to canopy and landscape. In theory, canopy spectral reflectance is regulated by leaf optical properties (reflectance and transmittance spectra) and canopy structure (geometrical distributions of leaf area and angle). In a deciduous broadleaf forest, our measurements and modeling analysis of leaf-level characteristics showed that seasonal changes in chlorophyll content and mesophyll structure of deciduous tree species lead to a seasonal change in leaf optical properties. The canopy reflectance spectrum of the deciduous forest also changes with season. In particular, canopy reflectance in the green region showed a unique pattern in the early growing season: green reflectance increased rapidly after leaf emergence and decreased rapidly after canopy closure. Our model simulation showed that the seasonal change in the leaf optical properties and leaf area index caused this pattern. Based on this understanding we discuss how we can gain ecophysiological information from satellite images at the landscape level. Finally, we discuss the challenges and opportunities of ecophysiological remote sensing by satellites.

在气候变化下，对陆地生态系统进行卫星遥感的需求日益增加。地球对光合作用和初级生产的观测从地方到全球范围的进一步进展，对于分析陆地生态系统的现状和光合生产力的变化至关重要。在本文中，我们回顾了影响森林冠层光学特性的植物生态生理过程，可以通过地球观测卫星的光学遥感对其进行测量。通过光学遥感测量的光谱反射率可用于估算冠层结构和初级生产力的时间和空间变化。光学信息反映了目标植被的物理特性；为了有效地使用这些信息，从单叶到冠层和景观的广泛尺度，对植物生态生理和光学特性的基本后果的机械理解是必不可少的。从理论上讲，冠层光谱反射率是由叶片的光学特性（反射率和透射光谱）和冠层结构（叶片面积和角度的几何分布）调节的。在落叶阔叶林中，我们对叶水平特征的测量和建模分析表明，落叶树种的叶绿素含量和叶肉结构的季节性变化导致叶片光学特性的季节性变化。落叶林的冠层反射光谱也随季节变化。特别是，绿色区域的树冠反射率在生长期早期显示出独特的模式：叶片出苗后，绿色反射率迅速增加，盖层关闭后，绿色反射率迅速下降。我们的模型仿真表明，叶片光学特性和叶片面积指数的季节性变化导致了这种模式。基于这种理解，我们讨论了如何从景观水平的卫星图像中获取生态生理信息。最后，我们讨论了卫星生态生理遥感的挑战和机遇。