Mechanistic evidence for tracking the seasonality of photosynthesis with solar-induced fluorescence
Mechanistic evidence for tracking the seasonality of photosynthesis with solar-induced fluorescence
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DOI：
10.1073/pnas.1900278116
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发表时间：
2019-06-11
影响因子：
11.1
通讯作者：
Frankenberg, Christian
中科院分区：
文献类型：
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作者：
Magney, Troy S.;Bowling, David R.;Frankenberg, Christian
北方的万年青森林吸收了全球大气中相当一部分的CO2，但监测这些系统中的大规模初级生产总值（GPP）的变化具有挑战性。遥感技术的最新进展使得可以检测植被的太阳诱导叶绿素荧光（SIF）发射，根据经验，这与大空间尺度上的GPP有关。这在万年青森林中尤其重要，因为传统的遥感技术和陆地生物圈模型无法再现全球生产力的季节性。在这里，我们研究了从冠层光谱仪系统检索到的SIF和GPP之间的机械关系在冬季休眠针叶林，这在冠层结构，针叶叶绿素含量和吸收光的季节变化不大。SIF和GPP都以一致的动态方式相互跟踪，以响应环境条件。SIF和GPP具有良好的相关性（R-2 = 0.62-0.92），在每小时至每周的时间尺度上具有不变的斜率。SIF产量的大的季节性变化捕获了与冬季驯化相关的光保护色素和光系统II运行效率的变化，突出了其精确跟踪光合作用季节性的独特能力。我们的研究结果强调了新的基于卫星的SIF产品（TROPOMI，OCO-2）作为代理的时间和规模的GPP在万年青森林在一个前所未有的时空分辨率的潜力。
Northern hemisphere evergreen forests assimilate a significant fraction of global atmospheric CO2 but monitoring large-scale changes in gross primary production (GPP) in these systems is challenging. Recent advances in remote sensing allow the detection of solar-induced chlorophyll fluorescence (SIF) emission from vegetation, which has been empirically linked to GPP at large spatial scales. This is particularly important in evergreen forests, where traditional remote-sensing techniques and terrestrial biosphere models fail to reproduce the seasonality of GPP. Here, we examined the mechanistic relationship between SIF retrieved from a canopy spectrometer system and GPP at a winter-dormant conifer forest, which has little seasonal variation in canopy structure, needle chlorophyll content, and absorbed light. Both SIF and GPP track each other in a consistent, dynamic fashion in response to environmental conditions. SIF and GPP are well correlated (R-2 = 0.62-0.92) with an invariant slope over hourly to weekly timescales. Large seasonal variations in SIF yield capture changes in photoprotective pigments and photosystem II operating efficiency associated with winter acclimation, highlighting its unique ability to precisely track the seasonality of photosynthesis. Our results underscore the potential of new satellite-based SIF products (TROPOMI, OCO-2) as proxies for the timing and magnitude of GPP in evergreen forests at an unprecedented spatiotemporal resolution.