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EO-1 Hyperion reflectance time series at calibration and validation sites: stability and sensitivity to seasonal dynamics

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing

By:
, , , , , ,
DOI: 10.1109/JSTARS.2013.2246139

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Abstract

This study evaluated Earth Observing 1 (EO-1) Hyperion reflectance time series at established calibration sites to assess the instrument stability and suitability for monitoring vegetation functional parameters. Our analysis using three pseudo-invariant calibration sites in North America indicated that the reflectance time series are devoid of apparent spectral trends and their stability consistently is within 2.5-5 percent throughout most of the spectral range spanning the 12+ year data record. Using three vegetated sites instrumented with eddy covariance towers, the Hyperion reflectance time series were evaluated for their ability to determine important variables of ecosystem function. A number of narrowband and derivative vegetation indices (VI) closely described the seasonal profiles in vegetation function and ecosystem carbon exchange (e.g., net and gross ecosystem productivity) in three very different ecosystems, including a hardwood forest and tallgrass prairie in North America, and a Miombo woodland in Africa. Our results demonstrate the potential for scaling the carbon flux tower measurements to local and regional landscape levels. The VIs with stronger relationships to the CO2 parameters were derived using continuous reflectance spectra and included wavelengths associated with chlorophyll content and/or chlorophyll fluorescence. Since these indices cannot be calculated from broadband multispectral instrument data, the opportunity to exploit these spectrometer-based VIs in the future will depend on the launch of satellites such as EnMAP and HyspIRI. This study highlights the practical utility of space-borne spectrometers for characterization of the spectral stability and uniformity of the calibration sites in support of sensor cross-comparisons, and demonstrates the potential of narrowband VIs to track and spatially extend ecosystem functional status as well as carbon processes measured at flux towers.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
EO-1 Hyperion reflectance time series at calibration and validation sites: stability and sensitivity to seasonal dynamics
Series title:
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
DOI:
10.1109/JSTARS.2013.2246139
Volume
6
Issue:
2
Year Published:
2013
Language:
English
Publisher:
IEEE Geoscience & Remote Sensing Society
Contributing office(s):
Denver Federal Center
Description:
15 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
276
Last page:
290
Number of Pages:
15
Country:
United States
State:
Nevada
Other Geospatial:
Frenchman Flat;Ivanpah Playa;Railroad Valley Playa