HR: 1340h
AN: B43D-1598    [Abstracts]
TI: Low-cost sensor packages for measuring narrowband canopy reflectance: implications for modeling regional C exchange
AU: * Vierling, L A
EM: leev@uidaho.edu
AF: Geospatial Laboratory for Environmental Dynamics, University of Idaho, CNR Building, University of Idaho, PO Box 441135, Moscow, ID 83844-1135, United States
AU: Naupari, J
EM: jnaupariv@vandals.uidaho.edu
AF: Geospatial Laboratory for Environmental Dynamics, University of Idaho, CNR Building, University of Idaho, PO Box 441135, Moscow, ID 83844-1135, United States
AU: Garrity, S R
EM: sgarrity@uidaho.edu
AF: Geospatial Laboratory for Environmental Dynamics, University of Idaho, CNR Building, University of Idaho, PO Box 441135, Moscow, ID 83844-1135, United States
AU: Guenther, A B
EM: guenther@ucar.edu
AF: National Center for Atmospheric Research, Atmospheric Chemistry Division P.O. Box 3000, Boulder, CO 80307-3000, United States
AU: Serca, D
EM: serd@aero.obs-mip.fr
AF: Laboratoire d'Aerologie, 14 Avenue Edouard Belin, Toulouse, 31400, France
AU: Burban, B
EM: benoit.burban@kourou.cirad.fr
AF: INRA Kourou - UMR Ecofog, BP 709, Kourou, 97387, French Guiana
AB: Recent advances in understanding the relationships between spectral reflectance of vegetation canopies and the structural/physiological drivers of canopy-atmosphere net ecosystem carbon exchange highlight the potential for using narrowband spectral vegetation indices to spatially scale C fluxes beyond the area of a tower footprint. However, ground reference observations of narrowband spectral reflectance in support of satellite observations can be challenging to obtain because 1) automated sampling of both upwelling and downwelling radiation is required over extended time periods to characterize diurnal and seasonal variability, 2) the quality of hyperspectral spectroradiometer data can be sensitive to environmental factors such as temperature and humidity, and 3) hyperspectral spectroradiometers are quite expensive, therefore greatly limiting prospects for widespread sampling. We have therefore developed lightweight (<0.5 kg), relatively low cost (ca. $325) sensor packages capable of measuring upwelling and downwelling radiation in 10nm-wide wavebands centered at 532 nm, 568 nm, 680 nm, and 800 nm, as well as the full PAR range (400-700 nm). These measurements can be combined to calculate several spectral characteristics (e.g. the photochemical reflectance index, PRI; the normalized difference vegetation index, NDVI; green NDVI, and the fraction PAR absorbed by the canopy, fPAR) found useful in modeling canopy trace gas exchange. Here, we discuss data collected using these sensor packages at shrub-steppe (Idaho, USA), mixed hardwood forest (Michigan, USA), and tropical rainforest (French Guiana) ecosystems and their implication for improving models of regional-scale carbon dioxide fluxes.
DE: 0428 Carbon cycling (4806)
DE: 0452 Instruments and techniques
DE: 0480 Remote sensing
DE: 0490 Trace gases
SC: Biogeosciences [B]
MN: 2007 Fall Meeting