Monitoring biosphere vegetation 1998–2009

Gobron, Nadine; Alan, Belward; Pinty, B.; Knorr, Wolfgang

doi:10.1029/2010gl043870

Cited by 58 publications

(38 citation statements)

References 14 publications

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“…[17] In addition to the MODIS data, we also used the JRC-fPAR product [Gobron et al, 2010]. The comparison showed a reasonable level of agreement between the two products with no overall bias ( Figure S2).…”

Section: Discussionmentioning

confidence: 99%

Evaluation of cropland maximum light use efficiency using eddy flux measurements in North America and Europe

Chen

Werf²,

Dolman³

et al. 2011

Geophys. Res. Lett.

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[1] Croplands cover 12% of the ice-free land surface and play an important role in the global carbon cycle. Light use efficiency (LUE) models have often been employed to estimate the exchange of CO 2 between croplands and the atmosphere. A key parameter in these models is the maximum light use efficiency ("*), but estimates of "* vary by at least a factor 2. Here we used 12 agricultural eddyflux measurement sites in North America and Europe to constrain LUE models in general and "* in particular. We found that LUE models could explain on average about 70% of the variability in net ecosystem exchange (NEE) when we increased the "* from 0.5 to 0.65-2.0g C per MJ Photosynthetic Active Radiation (PAR). Our results imply that croplands are more important in the global carbon budget than often thought. In addition, inverse modeling approaches that utilize LUE model outputs as a-priori input may have to be revisited in areas where croplands are an important contributor to regional carbon fluxes. Citation: Chen, T., G. R. van der Werf, A. J. Dolman, and M. Groenendijk (2011), Evaluation of cropland maximum light use efficiency using eddy flux measurements in North

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Section: Discussionmentioning

confidence: 99%

Evaluation of cropland maximum light use efficiency using eddy flux measurements in North America and Europe

Chen

Werf²,

Dolman³

et al. 2011

Geophys. Res. Lett.

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“…The Fraction of Photosynthetically Active Radiation (FPAR) is an important index for detecting the vegetation water, energy and carbon balance and is a key parameter in the ecosystem productivity model, crop yield model, and other models [1][2][3][4][5]. FPAR is most often defined as the proportion of available photosynthetically active radiation absorbed by the green vegetation canopy in the specific spectrum of 400-700 nm.…”

Section: Introductionmentioning

confidence: 99%

Assessment of MODIS, MERIS, GEOV1 FPAR Products over Northern China with Ground Measured Data and by Analyzing Residential Effect in Mixed Pixel

Yang

Ren

et al. 2014

Remote Sensing

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Fraction of Photosynthetically Active Radiation (FPAR) is a critical parameter in land surface energy balance and climate modeling. Several global FPAR products are available, but these still require considerable assessment and validation due to low spatial resolution. Three major FPAR products that have covered China and provided continuous time series data-MODIS, MERIS and GEOV1-were assessed from 2006-2010. Based on the ground measurement data, the accuracies of these three FPAR products were directly validated for maize and winter wheat over northern China. This investigation also assessed the consistencies among the three FPAR products, and analyzed the residential area in mixed pixels effect on the FPAR products accuracy, at each of the main growth stages of maize and winter wheat. The GEOV1 FPAR product was found to be the most accurate with regression R 2 values of 0.818 and 0.655 for ground measured maize and winter wheat FPAR. The maize FPAR data were generally more accurate than the winter wheat FPAR data. The MODIS, MERIS and GEOV1 products all indicated that FPAR variations among the growth stages differed from year to year. The scattered residential areas in mixed pixels were found to significantly affect the FPAR data uncertainties, and these were also analyzed in detail. The effect of residential area percentage in mixed pixels on FPAR values differed for different crops, and this was not necessarily in accordance 5429 with the FPAR product accuracy. For the mixed pixels, a quadratic polynomial was able to fit the residential area and FPAR data reasonably well with R 2 values higher than 0.9 for most relationships. Quadratic polynomial fitting may provide a simple and convenient method to assess and reduce the residential area effect on FPAR in the mixed pixels.

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“…To accurately achieve this, the FAPAR time series must be free of noise and trends caused by instrument-to-instrument variability. Gobron et al [25] already verified the possibility of merging FAPAR records at a global scale with a coarse spatial resolution from MERIS and SeaWiFS sensors.…”

Section: Jrc-fapar Productmentioning

confidence: 93%

Harmonization of Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) from Sea-ViewingWide Field-of-View Sensor (SeaWiFS) and Medium Resolution Imaging Spectrometer Instrument (MERIS)

2013

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This paper describes the combination of terrestrial vegetation observations from two sensors, providing a historical dataset used for an in-depth analysis of the corresponding spatio-temporal patterns. The Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) is an important variable suitable for regional to large-scale monitoring of climate impacts on vegetation. In this work, we create an extensive dataset of FAPAR using a 10-day product at ∼1 km resolution from September, 1997, to April, 2012, combining information from two sensors: the NASA/Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and the European Space Agency (ESA)/Medium Resolution Imaging Spectrometer Instrument (MERIS). The proposed methodology reduces the noise, fills the gaps and corrects for the spurious trends in the data, providing a time-consistent coverage of FAPAR. We develop a fast merging method and evaluate its performance over Europe and the Horn of Africa.

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Monitoring biosphere vegetation 1998–2009

Cited by 58 publications

References 14 publications

Evaluation of cropland maximum light use efficiency using eddy flux measurements in North America and Europe

Evaluation of cropland maximum light use efficiency using eddy flux measurements in North America and Europe

Assessment of MODIS, MERIS, GEOV1 FPAR Products over Northern China with Ground Measured Data and by Analyzing Residential Effect in Mixed Pixel

Harmonization of Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) from Sea-ViewingWide Field-of-View Sensor (SeaWiFS) and Medium Resolution Imaging Spectrometer Instrument (MERIS)

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