Heather Lawrence - Academia.edu (original) (raw)
Papers by Heather Lawrence
The work which we present takes place within the framework of mission SMOS of the ESA which will ... more The work which we present takes place within the framework of mission SMOS of the ESA which will consist to send a radiometer (1.4 GHz) in space. The goal of the research which we propose is the improvement of the comprehension of the effects of structure soil and litter. The effects of the litter and heterogeneities of the ground are probably important but still ignored. Its effect can be corrected via a simple radiative model. It is thus necessary to set up an analytical model which would make it possible to correct the effect of this additional layer. The objective of this article is to present the analytical models which we retained to correct the effect of the vegetation and the litter in order to know the emissivity of the bare soil. We developed a numerical model (with software HFSS) of calculation of the emissivity of multi-layer systems in order to validate the results of the forward inversion models. Ranges of permittivity are introduced with the model in order to take acc...
2012 IEEE International Geoscience and Remote Sensing Symposium, 2012
ABSTRACT The European Space Agency (ESA) Soil Moisture and Ocean Salinity mission (SMOS), was lau... more ABSTRACT The European Space Agency (ESA) Soil Moisture and Ocean Salinity mission (SMOS), was launched in November 2009. The payload for the mission was the Microwave Imaging Radiometer using Aperture Synthesis [1, 2]. Since the launch, global maps of brightness temperatures (TB) at L-band have been available. Angular characteristics of TB for horizontal and vertical polarization are used for the simultaneous retrieval of surface soil moisture (SM) and vegetation optical depth (TAU). Ground based radiometers such as the ELBARA-II radiometer [3] at the Valencia Anchor Station (VAS) are playing a key role in Calibration/Validation activities for this mission [4]. The L-band Microwave of the Emission of Biosphere model (L-MEB) is used to obtain level 2 products (SM, TAU) from T-B measured by SMOS [5]. It is important to first test all suggested improvements to L-MEB on ground-based data before implementing them into the SMOS algorithm. In this study, time series of radiometer measurements covering two vine vegetation periods were used to evaluate recent studies regarding L-MEB model with respect to this crop so significant and representative in many regions of the world. A good correlation between radiometer and SMOS TB was found (0.8). For the level 2 products, the correlation was less pronounced and varied with surface conditions and type of the orbit.
2012 IEEE International Geoscience and Remote Sensing Symposium, 2012
ABSTRACT Vegetation indices are indicators for analyzing the properties of vegetation. The Normal... more ABSTRACT Vegetation indices are indicators for analyzing the properties of vegetation. The Normalized Difference Vegetation Index (NDVI) from optical remote sensing data is one of the most commonly used vegetation indices, which can exhibit the ecological characteristics of leafy materials, but lacks the ability to directly provide information on the woody materials. In this paper, we developed Microwave Vegetation Indices (MVIs) from the L-band Soil Moisture and Ocean Salinity (SMOS) data, which is an effective means to detect the information of branches and trunks. The theory of MVIs is derived from the tau-omega model. To minimize the influence from the uncertain soil surface radiation, a parameterized database was built by the Advanced Integral Equation Model (AIEM). We selected two incidence angles (40° and 50°) and combined them to compute the MVIs. A simple method to evaluate the L-band optical thickness efficiently based on the MVI b-parameter (MVI-B). The MVI optical thickness(MVI-τ) was compared with the optical thickness retrieved from SMOS(SMOS-τ), and the results showed that the overall pattern was very similar.
ABSTRACT This study sought to gauge college sport video-game consumers’ ability to identify Natio... more ABSTRACT This study sought to gauge college sport video-game consumers’ ability to identify National Collegiate Athletic Association (NCAA) college football players, whose likenesses are featured in such games. The study also measured whether consumers perceived the use of athletes’ likenesses as sponsorship of these games, as well as whether certain demographic, usage, and other criteria may influence their positions on whether athletes should be compensated for such use, in excess of their current athletic scholarships. Findings point to the ability of consumers to identify athletes in the video games overall, and at a significantly higher percentage for nationally known football players whose likenesses are utilized in the games. Unsurprisingly, knowledge of college football as a sport, and of the video game series itself, significantly correlated with increased likelihood of identifying digital representations of real-life players. These and other findings, and their implications for NCAA policy and pending litigation related to student-athlete likenesses, are discussed.
IEEE Transactions on Geoscience and Remote Sensing
Health SA Gesondheid, 2014
2014 IEEE Geoscience and Remote Sensing Symposium, 2014
In this paper, roughness parameterizations providing best retrievals of soil moisture (SM) at L-b... more In this paper, roughness parameterizations providing best retrievals of soil moisture (SM) at L-band were evaluated. Different parameterizations were tested to find the best correlation R, bias and ubRMSE when comparing retrieved SM and in situ SM measurements carried out at the VAS (Valencia Anchor Station) over a vineyard field. Roughness measurements were always performed after the agricultural practices in the vineyard. These in situ data was used as input of the L-MEB (L-band Microwave Emission of the Biosphere) model, which permits the retrieval of SM and TAU (vegetation optical depth). In addition, a simplified method consisting on the retrieval of a parameter which combines the effects of roughness and TAU was tested. Significantly higher correlation (R=0.86) for SM was found using this method, while the absolute bias (-0.062) and RMSE (0.069) were slightly higher than for other roughness parameterizations.
Remote Sensing of Environment, 2014
The objective of this study was to compare several approaches to soil moisture (SM) retrieval usi... more The objective of this study was to compare several approaches to soil moisture (SM) retrieval using L-band microwave radiometry. The comparison was based on a brightness temperature (T B ) data set acquired since 2010 by the L-band radiometer ELBARA-II over a vineyard field at the Valencia Anchor Station (VAS) site. ELBARA-II, provided by the European Space Agency (ESA) within the scientific program of the SMOS (Soil Moisture and Ocean Salinity) mission, measures multiangular T B data at horizontal and vertical polarization for a range of incidence angles (30°-60°). Based on a three year data set (2010-2012), several SM retrieval approaches developed for spaceborne missions including AMSR-E (Advanced Microwave Scanning Radiometer for EOS), SMAP (Soil Moisture Active Passive) and SMOS were compared. The approaches include: the Single Channel Algorithm (SCA) for horizontal (SCA-H) and vertical (SCA-V) polarizations, the Dual Channel Algorithm (DCA), the Land Parameter Retrieval Model (LPRM) and two simplified approaches based on statistical regressions (referred to as 'Mattar' and 'Saleh'). Time series of vegetation indices required for three of the algorithms (SCA-H, SCA-V and 'Mattar') were obtained from MODIS observations. The SM retrievals were evaluated against reference SM values estimated from a multiangular 2-Parameter inversion approach. As no in situ SM data was used, the evaluation made here is relative to the use of this specific reference data set. The results obtained with the current base line algorithms developed for SMAP (SCA-H and -V) are in very good agreement with the 'reference' SM data set derived from the multi-angular observations (R 2 ≈ 0.90, RMSE varying between 0.035 and 0.056 m 3 /m 3 for several retrieval configurations). This result showed that, provided the relationship between vegetation optical depth and a remotely-sensed vegetation index can be calibrated, the SCA algorithms can provide results very close to those obtained from multi-angular observations in this study area. The approaches based on statistical regressions provided similar results and the best accuracy was obtained with the 'Saleh' methods based on either bi-angular or bipolarization observations (R 2 ≈ 0.93, RMSE ≈ 0.035 m 3 /m 3 ). The LPRM and DCA algorithms were found to be slightly less successful in retrieving the 'reference' SM time series (R 2 ≈ 0.75, RMSE ≈ 0.055 m 3 /m 3 ). However, the two above approaches have the great advantage of not requiring any model calibrations previous to the SM retrievals.
IMS (Bordeaux 1 University) and INRA-EPHYSE laboratories are currently taking part in the study a... more IMS (Bordeaux 1 University) and INRA-EPHYSE laboratories are currently taking part in the study and validation of the L-MEB inversion algorithm used for the SMOS (Soil Moisture and Ocean Salinity) mission. This mission will carry a 1.4 GHz (L-Band) interferometer which will ...
New Directions for Community Colleges, 2009
This chapter presents pertinent topics for institutional leaders to consider in developing and ma... more This chapter presents pertinent topics for institutional leaders to consider in developing and maintaining a community college athletic program. The authors present a "road map" for institutional decision makers involved in expanding, eliminating, or maintaining athletic teams and programs.
Team Performance Management, 2009
Purpose The purpose of this paper is to provide a framework for team selling to sports firms th... more Purpose The purpose of this paper is to provide a framework for team selling to sports firms that can be used to more effectively select members for sales and CRM teams and improve the performance of teams in attracting and retaining premium seating customers. Design/methodology ...
Remote Sensing of Environment, 2012
IEEE Transactions on Geoscience and Remote Sensing, 2000
In this study a physical modeling approach was used to evaluate the semi-empirical H − Q model, w... more In this study a physical modeling approach was used to evaluate the semi-empirical H − Q model, which is used in the SMOS retrieval algorithm to account for roughness effects over a bare soil. The modeling approach used for this study is based on Ansoft's High Frequency Structure Simulater (HFSS) software which solves Maxwell's equations using the Finite Element Method (FEM). It was presented recently and found to agree with the Method of Moments to within ∼3K.
![Research paper thumbnail of Correction to "Evaluating an improved parameterization of the soil emission in L-MEB" [Apr 11 1177-1189]](https://attachments.academia-assets.com/41911899/thumbnails/1.jpg)
](IEEE Transactions on Geoscience and Remote Sensing, 2000
ABSTRACT In the above paper (ibid., vol. 49, no. 4, pp. 1177-1189, Apr. 2011), there is an error ... more ABSTRACT In the above paper (ibid., vol. 49, no. 4, pp. 1177-1189, Apr. 2011), there is an error in equation (7). The explanation and corrected equation are presented here.
IEEE Geoscience and Remote Sensing Letters, 2000
This article has been accepted for inclusion in a future issue of this journal. Content is final ... more This article has been accepted for inclusion in a future issue of this journal. Content is final as presented, with the exception of pagination. ... IEEE GEOSCIENCE AND REMOTE SENSING LETTERS, VOL. 8, NO. 5, SEPTEMBER 2011 ... Based on the Finite-Element Method for ...
Arxiv preprint arXiv:0906.4686, 2009
Résumé : Dans le cadre de la mission SMOS EPHYSE sont parties prenantes dans l'étude et la c... more Résumé : Dans le cadre de la mission SMOS EPHYSE sont parties prenantes dans l'étude et la cette étude, nous avons développé un modèle ra de calculer l'émissivité de systèmes multicouch démarche afin d'intégrer de nouveaux para mesures. En effet, jusqu'à présent l'effet de ...
The work which we present takes place within the framework of mission SMOS of the ESA which will ... more The work which we present takes place within the framework of mission SMOS of the ESA which will consist to send a radiometer (1.4 GHz) in space. The goal of the research which we propose is the improvement of the comprehension of the effects of structure soil and litter. The effects of the litter and heterogeneities of the ground are probably important but still ignored. Its effect can be corrected via a simple radiative model. It is thus necessary to set up an analytical model which would make it possible to correct the effect of this additional layer. The objective of this article is to present the analytical models which we retained to correct the effect of the vegetation and the litter in order to know the emissivity of the bare soil. We developed a numerical model (with software HFSS) of calculation of the emissivity of multi-layer systems in order to validate the results of the forward inversion models. Ranges of permittivity are introduced with the model in order to take acc...
2012 IEEE International Geoscience and Remote Sensing Symposium, 2012
ABSTRACT The European Space Agency (ESA) Soil Moisture and Ocean Salinity mission (SMOS), was lau... more ABSTRACT The European Space Agency (ESA) Soil Moisture and Ocean Salinity mission (SMOS), was launched in November 2009. The payload for the mission was the Microwave Imaging Radiometer using Aperture Synthesis [1, 2]. Since the launch, global maps of brightness temperatures (TB) at L-band have been available. Angular characteristics of TB for horizontal and vertical polarization are used for the simultaneous retrieval of surface soil moisture (SM) and vegetation optical depth (TAU). Ground based radiometers such as the ELBARA-II radiometer [3] at the Valencia Anchor Station (VAS) are playing a key role in Calibration/Validation activities for this mission [4]. The L-band Microwave of the Emission of Biosphere model (L-MEB) is used to obtain level 2 products (SM, TAU) from T-B measured by SMOS [5]. It is important to first test all suggested improvements to L-MEB on ground-based data before implementing them into the SMOS algorithm. In this study, time series of radiometer measurements covering two vine vegetation periods were used to evaluate recent studies regarding L-MEB model with respect to this crop so significant and representative in many regions of the world. A good correlation between radiometer and SMOS TB was found (0.8). For the level 2 products, the correlation was less pronounced and varied with surface conditions and type of the orbit.
2012 IEEE International Geoscience and Remote Sensing Symposium, 2012
ABSTRACT Vegetation indices are indicators for analyzing the properties of vegetation. The Normal... more ABSTRACT Vegetation indices are indicators for analyzing the properties of vegetation. The Normalized Difference Vegetation Index (NDVI) from optical remote sensing data is one of the most commonly used vegetation indices, which can exhibit the ecological characteristics of leafy materials, but lacks the ability to directly provide information on the woody materials. In this paper, we developed Microwave Vegetation Indices (MVIs) from the L-band Soil Moisture and Ocean Salinity (SMOS) data, which is an effective means to detect the information of branches and trunks. The theory of MVIs is derived from the tau-omega model. To minimize the influence from the uncertain soil surface radiation, a parameterized database was built by the Advanced Integral Equation Model (AIEM). We selected two incidence angles (40° and 50°) and combined them to compute the MVIs. A simple method to evaluate the L-band optical thickness efficiently based on the MVI b-parameter (MVI-B). The MVI optical thickness(MVI-τ) was compared with the optical thickness retrieved from SMOS(SMOS-τ), and the results showed that the overall pattern was very similar.
ABSTRACT This study sought to gauge college sport video-game consumers’ ability to identify Natio... more ABSTRACT This study sought to gauge college sport video-game consumers’ ability to identify National Collegiate Athletic Association (NCAA) college football players, whose likenesses are featured in such games. The study also measured whether consumers perceived the use of athletes’ likenesses as sponsorship of these games, as well as whether certain demographic, usage, and other criteria may influence their positions on whether athletes should be compensated for such use, in excess of their current athletic scholarships. Findings point to the ability of consumers to identify athletes in the video games overall, and at a significantly higher percentage for nationally known football players whose likenesses are utilized in the games. Unsurprisingly, knowledge of college football as a sport, and of the video game series itself, significantly correlated with increased likelihood of identifying digital representations of real-life players. These and other findings, and their implications for NCAA policy and pending litigation related to student-athlete likenesses, are discussed.
IEEE Transactions on Geoscience and Remote Sensing
Health SA Gesondheid, 2014
2014 IEEE Geoscience and Remote Sensing Symposium, 2014
In this paper, roughness parameterizations providing best retrievals of soil moisture (SM) at L-b... more In this paper, roughness parameterizations providing best retrievals of soil moisture (SM) at L-band were evaluated. Different parameterizations were tested to find the best correlation R, bias and ubRMSE when comparing retrieved SM and in situ SM measurements carried out at the VAS (Valencia Anchor Station) over a vineyard field. Roughness measurements were always performed after the agricultural practices in the vineyard. These in situ data was used as input of the L-MEB (L-band Microwave Emission of the Biosphere) model, which permits the retrieval of SM and TAU (vegetation optical depth). In addition, a simplified method consisting on the retrieval of a parameter which combines the effects of roughness and TAU was tested. Significantly higher correlation (R=0.86) for SM was found using this method, while the absolute bias (-0.062) and RMSE (0.069) were slightly higher than for other roughness parameterizations.
Remote Sensing of Environment, 2014
The objective of this study was to compare several approaches to soil moisture (SM) retrieval usi... more The objective of this study was to compare several approaches to soil moisture (SM) retrieval using L-band microwave radiometry. The comparison was based on a brightness temperature (T B ) data set acquired since 2010 by the L-band radiometer ELBARA-II over a vineyard field at the Valencia Anchor Station (VAS) site. ELBARA-II, provided by the European Space Agency (ESA) within the scientific program of the SMOS (Soil Moisture and Ocean Salinity) mission, measures multiangular T B data at horizontal and vertical polarization for a range of incidence angles (30°-60°). Based on a three year data set (2010-2012), several SM retrieval approaches developed for spaceborne missions including AMSR-E (Advanced Microwave Scanning Radiometer for EOS), SMAP (Soil Moisture Active Passive) and SMOS were compared. The approaches include: the Single Channel Algorithm (SCA) for horizontal (SCA-H) and vertical (SCA-V) polarizations, the Dual Channel Algorithm (DCA), the Land Parameter Retrieval Model (LPRM) and two simplified approaches based on statistical regressions (referred to as 'Mattar' and 'Saleh'). Time series of vegetation indices required for three of the algorithms (SCA-H, SCA-V and 'Mattar') were obtained from MODIS observations. The SM retrievals were evaluated against reference SM values estimated from a multiangular 2-Parameter inversion approach. As no in situ SM data was used, the evaluation made here is relative to the use of this specific reference data set. The results obtained with the current base line algorithms developed for SMAP (SCA-H and -V) are in very good agreement with the 'reference' SM data set derived from the multi-angular observations (R 2 ≈ 0.90, RMSE varying between 0.035 and 0.056 m 3 /m 3 for several retrieval configurations). This result showed that, provided the relationship between vegetation optical depth and a remotely-sensed vegetation index can be calibrated, the SCA algorithms can provide results very close to those obtained from multi-angular observations in this study area. The approaches based on statistical regressions provided similar results and the best accuracy was obtained with the 'Saleh' methods based on either bi-angular or bipolarization observations (R 2 ≈ 0.93, RMSE ≈ 0.035 m 3 /m 3 ). The LPRM and DCA algorithms were found to be slightly less successful in retrieving the 'reference' SM time series (R 2 ≈ 0.75, RMSE ≈ 0.055 m 3 /m 3 ). However, the two above approaches have the great advantage of not requiring any model calibrations previous to the SM retrievals.
IMS (Bordeaux 1 University) and INRA-EPHYSE laboratories are currently taking part in the study a... more IMS (Bordeaux 1 University) and INRA-EPHYSE laboratories are currently taking part in the study and validation of the L-MEB inversion algorithm used for the SMOS (Soil Moisture and Ocean Salinity) mission. This mission will carry a 1.4 GHz (L-Band) interferometer which will ...
New Directions for Community Colleges, 2009
This chapter presents pertinent topics for institutional leaders to consider in developing and ma... more This chapter presents pertinent topics for institutional leaders to consider in developing and maintaining a community college athletic program. The authors present a "road map" for institutional decision makers involved in expanding, eliminating, or maintaining athletic teams and programs.
Team Performance Management, 2009
Purpose The purpose of this paper is to provide a framework for team selling to sports firms th... more Purpose The purpose of this paper is to provide a framework for team selling to sports firms that can be used to more effectively select members for sales and CRM teams and improve the performance of teams in attracting and retaining premium seating customers. Design/methodology ...
Remote Sensing of Environment, 2012
IEEE Transactions on Geoscience and Remote Sensing, 2000
In this study a physical modeling approach was used to evaluate the semi-empirical H − Q model, w... more In this study a physical modeling approach was used to evaluate the semi-empirical H − Q model, which is used in the SMOS retrieval algorithm to account for roughness effects over a bare soil. The modeling approach used for this study is based on Ansoft's High Frequency Structure Simulater (HFSS) software which solves Maxwell's equations using the Finite Element Method (FEM). It was presented recently and found to agree with the Method of Moments to within ∼3K.
IEEE Transactions on Geoscience and Remote Sensing, 2000
ABSTRACT In the above paper (ibid., vol. 49, no. 4, pp. 1177-1189, Apr. 2011), there is an error ... more ABSTRACT In the above paper (ibid., vol. 49, no. 4, pp. 1177-1189, Apr. 2011), there is an error in equation (7). The explanation and corrected equation are presented here.
IEEE Geoscience and Remote Sensing Letters, 2000
This article has been accepted for inclusion in a future issue of this journal. Content is final ... more This article has been accepted for inclusion in a future issue of this journal. Content is final as presented, with the exception of pagination. ... IEEE GEOSCIENCE AND REMOTE SENSING LETTERS, VOL. 8, NO. 5, SEPTEMBER 2011 ... Based on the Finite-Element Method for ...
Arxiv preprint arXiv:0906.4686, 2009
Résumé : Dans le cadre de la mission SMOS EPHYSE sont parties prenantes dans l'étude et la c... more Résumé : Dans le cadre de la mission SMOS EPHYSE sont parties prenantes dans l'étude et la cette étude, nous avons développé un modèle ra de calculer l'émissivité de systèmes multicouch démarche afin d'intégrer de nouveaux para mesures. En effet, jusqu'à présent l'effet de ...