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Record 43 of 3305
Using optical-microwave synergy for estimating surface energy fluxes over semi-arid rangeland
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Author and Affiliation:
Troufleau, D.(Centre Machinisme Agricole Genie Rural Eaux Forets, Montpellier, France)
Vidal, A.(Centre Machinisme Agricole Genie Rural Eaux Forets, Montpellier, France)
Beaudoin, A.(Centre Machinisme Agricole Genie Rural Eaux Forets, Montpellier, France)
Moran, M. S.(Agricultural Research Service, Phoenix, AZ., United States)
Weltz, M. A.(Department of Agriculture, Tucson, AZ., United States)
Goodrich, D. C.(Department of Agriculture, Tucson, AZ., United States)
Washburn, J.(Arizona Univ., Tucson, AZ., United States)
Rahman, A. F.(Arizona Univ., Tucson, AZ., United States)
Abstract: First results of the Walnut Gulch '92 (Arizona, U.S.) experiment concerning the combined use of radar backscattering (ERS-1) and thermal infrared (LANDSAT TM (Thematic Mapper)) data to estimate surface sensible heat flux are reported. The first step investigates the potential use of ERS-1 SAR (Synthetic Aperture Radar) images for surface soil moisture monitoring of the watershed using five calibrated images acquired during the year 1992 (dry to wet conditions). Results show that despite the typical low level of biomass of semi arid rangeland, an attenuation of the soil backscatter (up to 2 dB) can occur during the rainy season mainly due to the vegetation characteristics. A statistical relationship is then used to retrieve the volumetric surface soil moisture from ERS-1 backscattering (sensitivity of 0.23 dB/% moisture) with a resulting root mean square error of 1.3% of soil moisture. In a second step a semi empirical approach based on energy balance relates soil temperatures to this estimated surface soil moisture. Vegetation temperature is then deduced from soil temperatures and LANDSAT TM composite temperature in order to estimate sensible heat flux according to a two layer type model providing an RMSE of 29 W/sq m.
Publication Date: Jan 01, 1994
Document ID:
19950010708
(Acquired Dec 28, 1995)
Accession Number: 95N17123
Subject Category: EARTH RESOURCES AND REMOTE SENSING
Document Type: Conference Paper
Publication Information: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 1167-1174
Publisher Information: France
Contract/Grant/Task Num: NAGW-2425; NASA PROJ. IDP-88-086; NSF BSC-89-20851
Financial Sponsor: NASA; United States
Organization Source: Centre Machinisme Agricole Genie Rural Eaux Forets; Remote Sensing Lab.; Montpellier, France
Description: 8p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: ARID LANDS; BACKSCATTERING; HEAT FLUX; RANGELANDS; SATELLITE IMAGERY; SOIL MOISTURE; SYNTHETIC APERTURE RADAR; TEMPERATURE MEASUREMENT; THERMAL MAPPING; ERS-1 (ESA SATELLITE); MATHEMATICAL MODELS; RADAR MEASUREMENT; RADAR SIGNATURES; REMOTE SENSING; STATISTICAL ANALYSIS; THEMATIC MAPPERS (LANDSAT)
Imprint And Other Notes: In CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing p 1167-1174 (SEE N95-16983 04-43)
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