Using leaf chlorophyll to parameterize light-use-efficiency within a thermal-based carbon, water and energy exchange model
Using leaf chlorophyll to parameterize light-use-efficiency within a thermal-based carbon, water and energy exchange model
复制标题
DOI：
10.1016/j.rse.2011.02.027
复制
发表时间：
2011-07-15
影响因子：
13.5
通讯作者：
Rodell, Matthew
中科院分区：
文献类型：
--
作者：
Houborg, Rasmus;Anderson, Martha C.;Rodell, Matthew
叶绿素吸收光合有效辐射，因此作为光合作用的重要色素，这使得叶片叶绿素含量（C-ab）可用于监测植被生产力和整体植物生理状况的重要指标。本研究探讨的效用集成遥感估计C-AB到一个基于热的双源能量平衡（TSEB）模型，估计地表CO2和能量通量的分析，光利用效率（LUE）的方法来估计散装冠层阻力。LUE模型组件计算冠层尺度的碳同化和蒸腾通量，根据环境条件的短期变化从名义（物种相关）值（LUEn）内部估计有效LUE的波动。然而，LUEn可能在每天的时间尺度上变化，响应于植物物候、生理条件和营养状况的变化。因此，遥感方法，以提高每日估计LUEn进行了调查。利用涡度相关CO2通量塔观测资料，对美国马里兰州的一个异质玉米田进行了LUEn的逐日变化分析。优化的每日LUEn值进行比较，网格估计的C-ab塔通量足迹，检索从冠层反射率模型驱动的绿色，红色和近红外图像与飞机成像系统。塔校准的LUEn数据一般与机载检索的C-ab，和每小时的水，能源和碳通量估计精度TSEB显着提高时，使用C-ab描绘时空变化的LUEn。这项研究突出了热红外和短波反射波段在产生有价值的遥感数据以在两源能量平衡框架内估计碳、水和热通量方面的潜在协同作用。(C)2011 Elsevier Inc. All rights reserved.
Chlorophylls absorb photosynthetically active radiation and thus function as vital pigments for photosynthesis, which makes leaf chlorophyll content (C-ab) useful for monitoring vegetation productivity and an important indicator of the overall plant physiological condition. This study investigates the utility of integrating remotely sensed estimates of C-ab into a thermal-based Two-Source Energy Balance (TSEB) model that estimates land-surface CO2 and energy fluxes using an analytical, light-use-efficiency (LUE) approach to estimating bulk canopy resistance. The LUE model component computes canopy-scale carbon assimilation and transpiration fluxes, internally estimating fluctuations in effective LUE from a nominal (species-dependent) value (LUEn) in response to short-term variations in environmental conditions. LUEn, however, may vary on a daily timescale, responding to changes in plant phenology, physiological condition and nutrient status. Therefore, remote sensing methodologies for improving daily estimates of LUEn have been investigated. Day-to-day variations in LUEn were assessed for a heterogeneous corn crop field in Maryland, U.S.A. through model optimization with eddy covariance CO2 flux tower observations. The optimized daily LUEn values were then compared to gridded estimates of C-ab over the tower flux footprint, retrieved from a canopy reflectance model driven by green, red and near-infrared imagery acquired with an aircraft imaging system. The tower-calibrated LUEn data were generally well correlated with airborne retrievals of C-ab, and hourly water, energy and carbon flux estimation accuracies from TSEB were significantly improved when using C-ab for delineating spatio-temporal variations in LUEn. The study highlights the potential synergy between thermal infrared and shortwave reflective wavebands in producing valuable remote sensing data for estimating carbon, water and heat fluxes within a two-source energy balance framework. (C) 2011 Elsevier Inc. All rights reserved.