Global Retrievals of Solar-Induced Chlorophyll Fluorescence With TROPOMI: First Results and Intersensor Comparison to OCO-2
Global Retrievals of Solar-Induced Chlorophyll Fluorescence With TROPOMI: First Results and Intersensor Comparison to OCO-2
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DOI：
10.1029/2018gl079031
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发表时间：
2018-10-16
影响因子：
5.2
通讯作者：
Landgraf, Jochen
中科院分区：
文献类型：
--
作者：
Kohler, Philipp;Frankenberg, Christian;Landgraf, Jochen
近年来，太阳诱导叶绿素荧光（SIF）从星载光谱仪检索已被广泛用作在相对稀疏的时间和空间尺度的陆地光合作用的代理。最近发射的对流层监测仪器的近红外波段具有所需的光谱分辨率和信噪比，可在没有大气吸收特征的光谱范围内检索应力强度因子。我们发现，初始TROPOMI光谱满足高期望的时空分辨率大幅提高（高达7公里× 3.5公里的像素，每天重访），代表了一个步骤的变化，在SIF遥感能力。然而，解释需要谨慎，因为TROPOMI的2，600公里宽的扫描带所覆盖的广泛的观察照明几何形状需要考虑在内。与OCO-2的首次传感器间比较（Orbiting Carbon Observatory-2）SIF显示出极好的一致性，强调了TROPOMI的SIF反演的高质量和仪器的显著辐射性能。简明语言摘要光合作用是地球上生命最重要的过程，但逐渐变化的环境条件，如大气痕量气体浓度增加，温度上升，或减少的水可利用性可能不利地影响光合生产力。最近发射的对流层监测仪器旨在以前所未有的空间和时间分辨率监测大气痕量气体和空气污染物，而其辐射性能也使我们能够看到光合作用活跃的植被太阳诱导叶绿素荧光发出的微弱电磁信号。越来越多的证据表明，卫星仪器的SIF观测增强了我们跟踪陆地植被光合性能和碳吸收的能力。在这项研究中，我们提出了第一个对流层监测仪器SIF检索，在很大程度上优于以前和现有的空间连续监测SIF从空间的能力。
In recent years, solar-induced chlorophyll fluorescence (SIF) retrieved from spaceborne spectrometers has been extensively used as a proxy for terrestrial photosynthesis at relatively sparse temporal and spatial scales. The near-infrared band of the recently launched TROPOspheric Monitoring Instrument (TROPOMI) features the required spectral resolution and signal-to-noise ratio to retrieve SIF in a spectral range devoid of atmospheric absorption features. We find that initial TROPOMI spectra meet high expectations for a substantially improved spatiotemporal resolution (up to 7-km x 3.5-km pixels with daily revisit), representing a step change in SIF remote sensing capabilities. However, interpretation requires caution, as the broad range of viewing-illumination geometries covered by TROPOMI's 2,600-km-wide swath needs to be taken into account. A first intersensor comparison with OCO-2 (Orbiting Carbon Observatory-2) SIF shows excellent agreement, underscoring the high quality of TROPOMI's SIF retrievals and the notable radiometric performance of the instrument.Plain Language Summary Photosynthesis is the most essential process for life on Earth, but gradually changing environmental conditions such as increasing concentrations of atmospheric trace gases, rising temperatures, or reduced water availability could adversely affect the photosynthetic productivity. The recently launched TROPOspheric Monitoring Instrument is designed to monitor atmospheric trace gases and air pollutants with an unprecedented resolution in space and time, while its radiometric performance also permits us to see a weak electromagnetic signal emitted by photosynthetically active vegetation-solar-induced chlorophyll fluorescence (SIF). Mounting evidence suggests that SIF observations from satellite instruments augment our abilities to track the photosynthetic performance and carbon uptake of terrestrial vegetation. In this study, we present the first TROPOspheric Monitoring Instrument SIF retrievals, largely outperforming previous and existing capabilities for a spatial continuous monitoring of SIF from space.