Optical-Microwave Synergy for Estimating Surface Sensible Heat Flux over a Semi-Arid Rangeland

D. Troufleau, A. Vidal, A. Beaudoin, M. S. Moran, M. A. Weltz, D. C. Goodrich, James Washburne, A. F. Rahman

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

This study reports the first results of the Walnut Gulch' 92 experiment concerning the combined use of radar backscattering (ERS-1) and thermal infrared (Landsat TM) data to estimate surface sensible heat flux. The purpose is to use the radar/thermal synergy to retrieve both vegetation and soil temperatures required by a two-layer type model. The first step investigates the potential use of ERS-1 SAR 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 (RMSE) of 1.3% of soil moisture. In a second step a semi-empirical approach based on energy balance relates soil temperature Ts to this estimated surface soil moisture with an accuracy of 1.3°C. Vegetation temperature is then deduced from both Ts and Landsat TM composite temperature Tr in order to estimate sensible heat flux according to the two-layer model. To extenture measuremend the validation data set, additional Ts and Tr values are also obtained from ground soil moists and thermal aircraft flights respectively. The overall low RMSE of 35 W/m2 obtained between ground and remote sensible heat flux confirms the potentiality of radar/thermal synergy over semi-arid sparse vegetation for energy fluxes estimate.

Original languageEnglish (US)
Pages (from-to)113-132
Number of pages20
JournalRemote Sensing Reviews
Volume15
Issue number1-4
DOIs
StatePublished - Jan 1 1997

Fingerprint

rangelands
soil moisture
Soil moisture
sensible heat flux
vegetation
synergy
ERS-1 (ESA satellite)
rangeland
heat
Heat flux
heat flux
soils
estimating
Microwaves
Soils
radar
microwaves
Radar
root-mean-square errors
Backscattering

ASJC Scopus subject areas

  • Geography, Planning and Development
  • Instrumentation

Cite this

Troufleau, D., Vidal, A., Beaudoin, A., Moran, M. S., Weltz, M. A., Goodrich, D. C., ... Rahman, A. F. (1997). Optical-Microwave Synergy for Estimating Surface Sensible Heat Flux over a Semi-Arid Rangeland. Remote Sensing Reviews, 15(1-4), 113-132. https://doi.org/10.1080/02757259709532334

Optical-Microwave Synergy for Estimating Surface Sensible Heat Flux over a Semi-Arid Rangeland. / Troufleau, D.; Vidal, A.; Beaudoin, A.; Moran, M. S.; Weltz, M. A.; Goodrich, D. C.; Washburne, James; Rahman, A. F.

In: Remote Sensing Reviews, Vol. 15, No. 1-4, 01.01.1997, p. 113-132.

Research output: Contribution to journalArticle

Troufleau, D, Vidal, A, Beaudoin, A, Moran, MS, Weltz, MA, Goodrich, DC, Washburne, J & Rahman, AF 1997, 'Optical-Microwave Synergy for Estimating Surface Sensible Heat Flux over a Semi-Arid Rangeland', Remote Sensing Reviews, vol. 15, no. 1-4, pp. 113-132. https://doi.org/10.1080/02757259709532334
Troufleau D, Vidal A, Beaudoin A, Moran MS, Weltz MA, Goodrich DC et al. Optical-Microwave Synergy for Estimating Surface Sensible Heat Flux over a Semi-Arid Rangeland. Remote Sensing Reviews. 1997 Jan 1;15(1-4):113-132. https://doi.org/10.1080/02757259709532334
Troufleau, D. ; Vidal, A. ; Beaudoin, A. ; Moran, M. S. ; Weltz, M. A. ; Goodrich, D. C. ; Washburne, James ; Rahman, A. F. / Optical-Microwave Synergy for Estimating Surface Sensible Heat Flux over a Semi-Arid Rangeland. In: Remote Sensing Reviews. 1997 ; Vol. 15, No. 1-4. pp. 113-132.
@article{ed240e7e21214ecda061a330bd0e13bd,
title = "Optical-Microwave Synergy for Estimating Surface Sensible Heat Flux over a Semi-Arid Rangeland",
abstract = "This study reports the first results of the Walnut Gulch' 92 experiment concerning the combined use of radar backscattering (ERS-1) and thermal infrared (Landsat TM) data to estimate surface sensible heat flux. The purpose is to use the radar/thermal synergy to retrieve both vegetation and soil temperatures required by a two-layer type model. The first step investigates the potential use of ERS-1 SAR 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 (RMSE) of 1.3{\%} of soil moisture. In a second step a semi-empirical approach based on energy balance relates soil temperature Ts to this estimated surface soil moisture with an accuracy of 1.3°C. Vegetation temperature is then deduced from both Ts and Landsat TM composite temperature Tr in order to estimate sensible heat flux according to the two-layer model. To extenture measuremend the validation data set, additional Ts and Tr values are also obtained from ground soil moists and thermal aircraft flights respectively. The overall low RMSE of 35 W/m2 obtained between ground and remote sensible heat flux confirms the potentiality of radar/thermal synergy over semi-arid sparse vegetation for energy fluxes estimate.",
author = "D. Troufleau and A. Vidal and A. Beaudoin and Moran, {M. S.} and Weltz, {M. A.} and Goodrich, {D. C.} and James Washburne and Rahman, {A. F.}",
year = "1997",
month = "1",
day = "1",
doi = "10.1080/02757259709532334",
language = "English (US)",
volume = "15",
pages = "113--132",
journal = "Remote Sensing Reviews",
issn = "0275-7257",
publisher = "Taylor and Francis Ltd.",
number = "1-4",

}

TY - JOUR

T1 - Optical-Microwave Synergy for Estimating Surface Sensible Heat Flux over a Semi-Arid Rangeland

AU - Troufleau, D.

AU - Vidal, A.

AU - Beaudoin, A.

AU - Moran, M. S.

AU - Weltz, M. A.

AU - Goodrich, D. C.

AU - Washburne, James

AU - Rahman, A. F.

PY - 1997/1/1

Y1 - 1997/1/1

N2 - This study reports the first results of the Walnut Gulch' 92 experiment concerning the combined use of radar backscattering (ERS-1) and thermal infrared (Landsat TM) data to estimate surface sensible heat flux. The purpose is to use the radar/thermal synergy to retrieve both vegetation and soil temperatures required by a two-layer type model. The first step investigates the potential use of ERS-1 SAR 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 (RMSE) of 1.3% of soil moisture. In a second step a semi-empirical approach based on energy balance relates soil temperature Ts to this estimated surface soil moisture with an accuracy of 1.3°C. Vegetation temperature is then deduced from both Ts and Landsat TM composite temperature Tr in order to estimate sensible heat flux according to the two-layer model. To extenture measuremend the validation data set, additional Ts and Tr values are also obtained from ground soil moists and thermal aircraft flights respectively. The overall low RMSE of 35 W/m2 obtained between ground and remote sensible heat flux confirms the potentiality of radar/thermal synergy over semi-arid sparse vegetation for energy fluxes estimate.

AB - This study reports the first results of the Walnut Gulch' 92 experiment concerning the combined use of radar backscattering (ERS-1) and thermal infrared (Landsat TM) data to estimate surface sensible heat flux. The purpose is to use the radar/thermal synergy to retrieve both vegetation and soil temperatures required by a two-layer type model. The first step investigates the potential use of ERS-1 SAR 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 (RMSE) of 1.3% of soil moisture. In a second step a semi-empirical approach based on energy balance relates soil temperature Ts to this estimated surface soil moisture with an accuracy of 1.3°C. Vegetation temperature is then deduced from both Ts and Landsat TM composite temperature Tr in order to estimate sensible heat flux according to the two-layer model. To extenture measuremend the validation data set, additional Ts and Tr values are also obtained from ground soil moists and thermal aircraft flights respectively. The overall low RMSE of 35 W/m2 obtained between ground and remote sensible heat flux confirms the potentiality of radar/thermal synergy over semi-arid sparse vegetation for energy fluxes estimate.

UR - http://www.scopus.com/inward/record.url?scp=0030713282&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030713282&partnerID=8YFLogxK

U2 - 10.1080/02757259709532334

DO - 10.1080/02757259709532334

M3 - Article

VL - 15

SP - 113

EP - 132

JO - Remote Sensing Reviews

JF - Remote Sensing Reviews

SN - 0275-7257

IS - 1-4

ER -