Paper Info
Title
Relating a Spectral Index from MODIS and Tower-Based Measurements to Ecosystem Light Use Efficiency for a Fluxnet-Canada Coniferous Forest
Abstract
Hyperspectral reflectance data collected diurnally from an instrumented tower were examined in conjunction with the eddy correlation fluxes and meteorological measurements made throughout a growing season at a mature Douglas fir forest in British Columbia, Canada (DF49). Here we present 2006 in situ results relating the Photochemical Reflectance Index (PRI551) to photosynthetic light use efficiency (LUE). Canopy structure information was used to partition the forest canopy into sunlit and shaded fractions. At each observation period, the PRI551 was examined for the sunlit, shaded, and mixed sunlit/shaded canopy segments as defined by their instantaneous position relative to the solar principal plane (SPP). We show that the PRI551 clearly captures the differences in leaf groups on sunny days. We also examined PRI551 from MODIS ocean band imagery acquired over DF49 during a five year period (2001-2006) from both Terra (late morning) and Aqua (early afternoon) platforms. The MODIS observations from Terra and Aqua were acquired in different viewing planes above the landscape over a range of view zenith angles, and sampled the backscatter (sunlit) and forward scatter (shaded) sectors of the forest's bidirectional reflectance distribution function. When tower-based bulk canopy LUE from 2006 was recalculated to estimate foliage-based values for the three foliage groups under their incident light environments, a strong linear relationship with PRI551 was demonstrated (r2~0.80). A similar relationship between the MODIS PRI551 and tower-based bulk LUE was obtained from satellite observations (r2~0.62), but only for the backscatter observations obtained at high light levels (APAR, >1500 mumol m-2 s-1). The MODIS observations, while not ideal in terms of spatial resolution (> 1 km2) or optimal viewing configuration, nevertheless provided a means to m- - onitor forest under stress using narrow spectral band indices and off-nadir observations.
Year
DOI
Venue
2008
10.1109/IGARSS.2008.4778989
Geoscience and Remote Sensing Symposium, 2008. IGARSS 2008. IEEE International
Keywords
Field
DocType
atmospheric boundary layer,atmospheric radiation,sunlight,vegetation mapping,AD 2006,Aqua platforms,British Columbia,Canada,Douglas fir forest,Fluxnet-Canada,MODIS observation,Moderate Resolution Imaging Spectroradiometer,Photochemical Reflectance Index,Terra platforms,backscatter observation,coniferous forest,ecosystem light use efficiency,eddy correlation fluxes,forest canopy structure information,forest's bidirectional reflectance distribution function,forward scatter sectors,hyperspectral reflectance data collection,in situ,leaf groups,meteorological measurements,photosynthetic light use efficiency,satellite ocean band imagery,solar principal plane,spectral band indices,sunlit,tower-based measurements,Douglas fir,Light use efficiency,MODIS Aqua and Terra,Photochemical Reflectance Index
Bidirectional reflectance distribution function,Tree canopy,Moderate-resolution imaging spectroradiometer,FluxNet,Computer science,Remote sensing,Atmospheric sciences,Photosynthetically active radiation,Eddy covariance,Photochemical Reflectance Index,Canopy
Conference
Volume
ISBN
Citations 
2
978-1-4244-2808-3
0
PageRank 
References 
Authors
0.34
1
7
Name
Order
Citations
PageRank
Elizabeth M. Middleton19619.73
Yen-Ben Cheng2237.01
Thomas Hilker3136.75
Nicholas C. Coops412330.17
Karl Fred Huemmrich57317.23
T. Andrew Black600.68
Praveena Krishnan700.68