Corrigendum to “Unpacking the drivers of diurnal dynamics of sun-induced chlorophyll fluorescence (SIF): Canopy structure, plant physiology, instrument configuration and retrieval methods” [Remote Sensing of Environment 265 (2021) 112672]

<p>Solar-induced chlorophyll fluorescence (SIF) offers a promising tool to remotely monitor photosynthesis from the canopy to regional scale. However, in order to interpret instantaneous satellite SIF measurements in a biological context, there needs to be a better understanding of the diurnal dynamics of SIF and photosynthesis. Using two maize sites with contrasting row orientations, we acquired canopy scale SIF and hyperspectral reflectance using a tower and UAV, in conjunction with concurrent leaf-level measurements of photosynthesis and chlorophyll fluorescence. We show that SIF dynamics are impacted by a combination of canopy structure and plant physiology, which can lead to a divergent SIF-photosynthesis relationship, particularly at certain times of day. These findings have significant implications for upscaling and interpreting satellite SIF retrievals, which rely on daily mean integrals.</p>

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Plant ecophysiological processes in spectral profiles: perspective from a deciduous broadleaf forest

Journal of Plant Research ◽

10.1007/s10265-021-01302-7 ◽

2021 ◽

Author(s):

Hibiki M. Noda ◽

Hiroyuki Muraoka ◽

Kenlo Nishida Nasahara

Keyword(s):

Remote Sensing ◽

Optical Properties ◽

Spectral Reflectance ◽

Canopy Structure ◽

Terrestrial Ecosystems ◽

Optical Remote Sensing ◽

Canopy Reflectance ◽

Broadleaf Forest ◽

Leaf Optical Properties ◽

Deciduous Broadleaf Forest

AbstractThe 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.

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Remote Sensing of Solar-Induced Chlorophyll Fluorescence at Atmospheric Oxygen Absorption Band Around 760 nm and Simulation of That Absorption in Laboratory

IEEE Transactions on Geoscience and Remote Sensing ◽

10.1109/tgrs.2012.2185503 ◽

2012 ◽

Vol 50 (10) ◽

pp. 3908-3914 ◽

Cited By ~ 1

Author(s):

Barun RayChaudhuri

Keyword(s):

Remote Sensing ◽

Chlorophyll Fluorescence ◽

Absorption Band ◽

Atmospheric Oxygen ◽

Oxygen Absorption

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Canopy spectral invariants for remote sensing of canopy structure

2009 First Workshop on Hyperspectral Image and Signal Processing: Evolution in Remote Sensing ◽

10.1109/whispers.2009.5289105 ◽

2009 ◽

Author(s):

Yu. Knyazikhin ◽

M. Schull ◽

Liang Hu ◽

R. Myneni ◽

P.L. Carmona

Keyword(s):

Remote Sensing ◽

Canopy Structure ◽

Spectral Invariants

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Temporal Variation of Chlorophyll-a Concentrations in Highly Dynamic Waters from Unattended Sensors and Remote Sensing Observations

Sensors ◽

10.3390/s18082699 ◽

2018 ◽

Vol 18 (8) ◽

pp. 2699 ◽

Cited By ~ 2

Author(s):

Jian Li ◽

Liqiao Tian ◽

Qingjun Song ◽

Zhaohua Sun ◽

Hongjing Yu ◽

...

Keyword(s):

Remote Sensing ◽

Water Quality ◽

Chlorophyll Fluorescence ◽

Chlorophyll A ◽

Temporal Variations ◽

Lake Area ◽

Short Term ◽

Chl A ◽

Spatio Temporal

Monitoring of water quality changes in highly dynamic inland lakes is frequently impeded by insufficient spatial and temporal coverage, for both field surveys and remote sensing methods. To track short-term variations of chlorophyll fluorescence and chlorophyll-a concentrations in Poyang Lake, the largest freshwater lake in China, high-frequency, in-situ, measurements were collected from two fixed stations. The K-mean clustering method was also applied to identify clusters with similar spatio-temporal variations, using remote sensing Chl-a data products from the MERIS satellite, taken from 2003 to 2012. Four lake area classes were obtained with distinct spatio-temporal patterns, two of which were selected for in situ measurement. Distinct daily periodic variations were observed, with peaks at approximately 3:00 PM and troughs at night or early morning. Short-term variations of chlorophyll fluorescence and Chl-a levels were revealed, with a maximum intra-diurnal ratio of 5.1 and inter-diurnal ratio of 7.4, respectively. Using geostatistical analysis, the temporal range of chlorophyll fluorescence and corresponding Chl-a variations was determined to be 9.6 h, which indicates that there is a temporal discrepancy between Chl-a variations and the sampling frequency of current satellite missions. An analysis of the optimal sampling strategies demonstrated that the influence of the sampling time on the mean Chl-a concentrations observed was higher than 25%, and the uncertainty of any single Terra/MODIS or Aqua/MODIS observation was approximately 15%. Therefore, sampling twice a day is essential to resolve Chl-a variations with a bias level of 10% or less. The results highlight short-term variations of critical water quality parameters in freshwater, and they help identify specific design requirements for geostationary earth observation missions, so that they can better address the challenges of monitoring complex coastal and inland environments around the world.

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Mechanistic evidence for tracking the seasonality of photosynthesis with solar-induced fluorescence

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1900278116 ◽

2019 ◽

pp. 201900278 ◽

Cited By ~ 21

Author(s):

Troy S. Magney ◽

David R. Bowling ◽

Barry A. Logan ◽

Katja Grossmann ◽

Jochen Stutz ◽

...

Keyword(s):

Remote Sensing ◽

Large Scale ◽

Spatial Scales ◽

Gross Primary Production ◽

Canopy Structure ◽

Operating Efficiency ◽

Conifer Forest ◽

Spatiotemporal Resolution ◽

Evergreen Forests ◽

Spectrometer System

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 (R2 = 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.

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SIFSpec: Measuring Solar-Induced Chlorophyll Fluorescence Observations for Remote Sensing of Photosynthesis

Sensors ◽

10.3390/s19133009 ◽

2019 ◽

Vol 19 (13) ◽

pp. 3009 ◽

Cited By ~ 11

Author(s):

Shanshan Du ◽

Liangyun Liu ◽

Xinjie Liu ◽

Jian Guo ◽

Jiaochan Hu ◽

...

Keyword(s):

Remote Sensing ◽

Chlorophyll Fluorescence ◽

Seasonal Variations ◽

Photosynthetic Activity ◽

Gross Primary Production ◽

Atmospheric Correction ◽

Gansu Province ◽

Optical Measurements ◽

Calibration Data ◽

Flux Measurements

Solar-induced chlorophyll fluorescence (SIF) is regarded as a proxy for photosynthesis in terrestrial vegetation. Tower-based long-term observations of SIF are very important for gaining further insight into the ecosystem-specific seasonal dynamics of photosynthetic activity, including gross primary production (GPP). Here, we present the design and operation of the tower-based automated SIF measurement (SIFSpec) system. This system was developed with the aim of obtaining synchronous SIF observations and flux measurements across different terrestrial ecosystems, as well as to validate the increasing number of satellite SIF products using in situ measurements. Details of the system components, instrument installation, calibration, data collection, and processing are introduced. Atmospheric correction is also included in the data processing chain, which is important, but usually ignored for tower-based SIF measurements. Continuous measurements made across two growing cycles over maize at a Daman (DM) flux site (in Gansu province, China) demonstrate the reliable performance of SIF as an indicator for tracking the diurnal variations in photosynthetically active radiation (PAR) and seasonal variations in GPP. For the O2–A band in particular, a high correlation coefficient value of 0.81 is found between the SIF and seasonal variations of GPP. It is thus concluded that, in coordination with continuous eddy covariance (EC) flux measurements, automated and continuous SIF observations can provide a reliable approach for understanding the photosynthetic activity of the terrestrial ecosystem, and are also able to bridge the link between ground-based optical measurements and airborne or satellite remote sensing data.

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