Potential of solar-induced chlorophyll fluorescence to estimate transpiration in a temperate forest
Potential of solar-induced chlorophyll fluorescence to estimate transpiration in a temperate forest
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DOI：
10.1016/j.agrformet.2018.01.017
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发表时间：
2018-04-15
影响因子：
6.2
通讯作者：
Tang, Jianwu
中科院分区：
文献类型：
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作者：
Lu, Xiaoliang;Liu, Zhunqiao;Tang, Jianwu
通过利用连续测量的水通量和太阳诱导的叶绿素荧光（SIF）在整个生长季节，我们利用宽带SIF在预测植物蒸腾（T）在温带森林的潜力。在利用选择的吸收线重建完整的SIF光谱并利用SCOPE（Soil Canopy Observation Photochemistry and Energy Fluxs）模型进行模拟后，采用线性回归（LR）和高斯过程回归（GPR）模型分析了T与不同SIF波段组合之间的关系。我们发现，在近红外光谱（在720 nm，740 nm和760 nm）的SIF发射比在红色光谱（在685 nm和687 nm）的SIF发射更敏感的T。虽然条件，如光和热应力解耦单波段SIF和T之间的关系，不同的SIF波段的组合允许检索可靠的T估计，即使在这些条件下。总体而言，我们发现，使用SIF作为代理T产量估计，至少是准确的那些从传统的蒸腾模型，如Penman-Monteith方程，这是输入要求和复杂的应用到原位和卫星数据。研究结果表明：（1）当光合有效辐射（PAR）、水汽压亏缺和气温超过生物最适阈值时，SIF与T的相关性变差;（2）高叶面积指数会增加SIF信号的散射和（再）吸收，对SIF与T的相关性产生负面影响;（3）SIF-T的相关性不随观测时间的变化而变化;（4）时间聚集性进一步增强了SIF-T的相关性。总之，我们的研究结果提供了第一个地面的证据表明，SIF排放有可能是一个密切的预测植物蒸腾作用，特别是当不同的SIF波段的组合被认为是。
By utilizing continuous measurements of water fluxes and solar-induced chlorophyll fluorescence (SIF) over the entire growing season, we exploit the potential of broadband SIF in predicting plant transpiration (T) in a temperate forest. After reconstructing the full SIF spectrum from the selected absorption lines and simulations from the SCOPE (Soil Canopy Observation Photochemistry and Energy fluxes) model, linear regression (LR) and Gaussian processes regression (GPR) models are used to analyze the relation between T and combinations of different SIF bands. We find that SIF emissions in the near-infrared spectrum (at 720 nm, 740 nm and 760 nm) are more sensitive to T than SIF emissions in the red spectrum (at 685 nm and 687 nm). While conditions such as light and heat stress decouple the relationship between single-band SIF and T, the combination of different SIF bands allows the retrieval of reliable T estimates even in these conditions. Overall, we find that the use of SIF as a proxy for T yields estimates that are at least as accurate as those from traditional transpiration models such as the Penman-Monteith equation, which are input demanding and complex to apply to in situ and satellite data. Specifically, we find that (1) the SIF-T relationship deteriorates when Photosynthetically Active Radiation (PAR), vapor pressure deficit and air temperature exceed biological optimal thresholds; (2) a high leaf area index exerts a negative impact on the SIF-T correlation due to increasing scattering and (re)absorption of the SIF signal; (3) the SIF-T relationship does not change depending on the observation time during the day; and (4) temporal aggregation to days further enhanced the SIF-T correlations. Altogether, our results provide the first ground based evidence that SIF emission has potential to be a close predictor of plant transpiration, especially when a combination of different SIF bands is considered.