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J P Gastelluetchegorry - One of the best experts on this subject based on the ideXlab platform.
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the stochastic beer lambert Bouguer law for discontinuous vegetation canopies
Journal of Quantitative Spectroscopy & Radiative Transfer, 2018Co-Authors: N Shabanov, J P GastelluetchegorryAbstract:Abstract The 3D distribution of canopy foliage affects the radiation regime and retrievals of canopy biophysical parameters. The gap fraction is one primary indicator of a canopy structure. Historically the Beer–Lambert–Bouguer law and the linear mixture model have served as a basis for multiple technologies for retrievals of the gap (or vegetation) fraction and Leaf Area Index (LAI). The Beer–Lambert–Bouguer law is a form of the Radiative Transfer (RT) equation for homogeneous canopies, which was later adjusted for a correlation between fitoelements using concept of the clumping index. The Stochastic Radiative Transfer (SRT) approach has been developed specifically for heterogeneous canopies, however the approach lacks a proper model of the vegetation fraction. This study is focused on the implementation of the stochastic version of the Beer–Lambert–Bouguer law for heterogeneous canopies, featuring the following principles: 1) two mechanisms perform photon transport- transmission through the turbid medium of foliage crowns and direct streaming through canopy gaps, 2) the radiation field is influenced by a canopy structure (quantified by the statistical moments of a canopy structure) and a foliage density (quantified by the gap fraction as a function of LAI), 3) the notions of canopy transmittance and gap fraction are distinct. The derived stochastic Beer–Lambert–Bouguer law is consistent with the Geometrical Optical and Radiative Transfer (GORT) derivations. Analytical and numerical analysis of the stochastic Beer–Lambert–Bouguer law presented in this study provides the basis to reformulate widely used technologies for retrievals of the gap fraction and LAI from ground and satellite radiation measurements.
N Shabanov - One of the best experts on this subject based on the ideXlab platform.
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the stochastic beer lambert Bouguer law for discontinuous vegetation canopies
Journal of Quantitative Spectroscopy & Radiative Transfer, 2018Co-Authors: N Shabanov, J P GastelluetchegorryAbstract:Abstract The 3D distribution of canopy foliage affects the radiation regime and retrievals of canopy biophysical parameters. The gap fraction is one primary indicator of a canopy structure. Historically the Beer–Lambert–Bouguer law and the linear mixture model have served as a basis for multiple technologies for retrievals of the gap (or vegetation) fraction and Leaf Area Index (LAI). The Beer–Lambert–Bouguer law is a form of the Radiative Transfer (RT) equation for homogeneous canopies, which was later adjusted for a correlation between fitoelements using concept of the clumping index. The Stochastic Radiative Transfer (SRT) approach has been developed specifically for heterogeneous canopies, however the approach lacks a proper model of the vegetation fraction. This study is focused on the implementation of the stochastic version of the Beer–Lambert–Bouguer law for heterogeneous canopies, featuring the following principles: 1) two mechanisms perform photon transport- transmission through the turbid medium of foliage crowns and direct streaming through canopy gaps, 2) the radiation field is influenced by a canopy structure (quantified by the statistical moments of a canopy structure) and a foliage density (quantified by the gap fraction as a function of LAI), 3) the notions of canopy transmittance and gap fraction are distinct. The derived stochastic Beer–Lambert–Bouguer law is consistent with the Geometrical Optical and Radiative Transfer (GORT) derivations. Analytical and numerical analysis of the stochastic Beer–Lambert–Bouguer law presented in this study provides the basis to reformulate widely used technologies for retrievals of the gap fraction and LAI from ground and satellite radiation measurements.
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The stochastic Beer–Lambert–Bouguer law for discontinuous vegetation canopies
Journal of Quantitative Spectroscopy & Radiative Transfer, 2018Co-Authors: N Shabanov, Jean-philippe Gastellu-etchegorryAbstract:Abstract The 3D distribution of canopy foliage affects the radiation regime and retrievals of canopy biophysical parameters. The gap fraction is one primary indicator of a canopy structure. Historically the Beer–Lambert–Bouguer law and the linear mixture model have served as a basis for multiple technologies for retrievals of the gap (or vegetation) fraction and Leaf Area Index (LAI). The Beer–Lambert–Bouguer law is a form of the Radiative Transfer (RT) equation for homogeneous canopies, which was later adjusted for a correlation between fitoelements using concept of the clumping index. The Stochastic Radiative Transfer (SRT) approach has been developed specifically for heterogeneous canopies, however the approach lacks a proper model of the vegetation fraction. This study is focused on the implementation of the stochastic version of the Beer–Lambert–Bouguer law for heterogeneous canopies, featuring the following principles: 1) two mechanisms perform photon transport- transmission through the turbid medium of foliage crowns and direct streaming through canopy gaps, 2) the radiation field is influenced by a canopy structure (quantified by the statistical moments of a canopy structure) and a foliage density (quantified by the gap fraction as a function of LAI), 3) the notions of canopy transmittance and gap fraction are distinct. The derived stochastic Beer–Lambert–Bouguer law is consistent with the Geometrical Optical and Radiative Transfer (GORT) derivations. Analytical and numerical analysis of the stochastic Beer–Lambert–Bouguer law presented in this study provides the basis to reformulate widely used technologies for retrievals of the gap fraction and LAI from ground and satellite radiation measurements.
Will Featherstone - One of the best experts on this subject based on the ideXlab platform.
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Band‐limited Bouguer gravity identifies new basins on the Moon
Journal of Geophysical Research, 2013Co-Authors: Will Featherstone, Christian Hirt, Michael KuhnAbstract:[1] Spectral domain forward modeling is used to generate topography-implied gravity for the Moon using data from the Lunar Orbiter Laser Altimeter instrument operated on board the Lunar Reconnaissance Orbiter mission. This is subtracted from Selenological and Engineering Explorer (SELENE)-derived gravity to generate band-limited Bouguer gravity maps of the Moon so as to enhance the gravitational signatures of anomalous mass densities nearer the surface. This procedure adds evidence that two previously postulated basins on the lunar farside, Fitzgerald-Jackson (25°N, 191°E) and to the east of Debye (50°N, 180°E), are indeed real. When applied over the entire lunar surface, band-limited Bouguer gravity reveals the locations of 280 candidate basins that have not been identified when using full-spectrum gravity or topography alone, showing the approach to be of utility. Of the 280 basins, 66 are classified as distinct from their band-limited Bouguer gravity and topographic signatures, making them worthy of further investigation.
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band limited Bouguer gravity identifies new basins on the moon
Journal of Geophysical Research, 2013Co-Authors: Will Featherstone, Christian Hirt, Michael KuhnAbstract:[1] Spectral domain forward modeling is used to generate topography-implied gravity for the Moon using data from the Lunar Orbiter Laser Altimeter instrument operated on board the Lunar Reconnaissance Orbiter mission. This is subtracted from Selenological and Engineering Explorer (SELENE)-derived gravity to generate band-limited Bouguer gravity maps of the Moon so as to enhance the gravitational signatures of anomalous mass densities nearer the surface. This procedure adds evidence that two previously postulated basins on the lunar farside, Fitzgerald-Jackson (25°N, 191°E) and to the east of Debye (50°N, 180°E), are indeed real. When applied over the entire lunar surface, band-limited Bouguer gravity reveals the locations of 280 candidate basins that have not been identified when using full-spectrum gravity or topography alone, showing the approach to be of utility. Of the 280 basins, 66 are classified as distinct from their band-limited Bouguer gravity and topographic signatures, making them worthy of further investigation.
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complete spherical Bouguer gravity anomalies over australia
Australian Journal of Earth Sciences, 2009Co-Authors: Michael Kuhn, Will Featherstone, Jonathan KirbyAbstract:Complete (or refined) spherical Bouguer gravity anomalies have been computed for all 1 095 065 land gravity observations in the June 2007 release of the Australian national gravity database. The spherical Bouguer shell contribution was computed using the supplied ground elevations of the gravity observations. The spherical terrain corrections, residual to each Bouguer shell, were computed on a 9 arc-second grid (∼250 m by ∼250 m spatial resolution) from a global Newtonian integration using heights from version 2.1 of the GEODATA digital elevation model (DEM) over Australia and the GLOBE and JGP95E global DEMs outside Australia. A constant topographic mass-density of 2670 kg/m3 was used for both the spherical Bouguer shell and spherical terrain correction terms. The difference between the complete spherical and complete planar Bouguer gravity anomaly exhibits an almost constant bias of about −18.7 mGal over areas with moderate elevation changes, thus verifying the planar model as a reasonable approximation...
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new views of the spherical Bouguer gravity anomaly
Geophysical Journal International, 2004Co-Authors: Petr Vaníček, Lars E Sjoberg, Z Martinec, Robert Tenzer, Will FeatherstoneAbstract:SUMMARY This paper presents a number of new concepts concerning the gravity anomaly. First, it identifies a distinct difference between a surface (2-D) gravity anomaly (the difference between actual gravity on one surface and normal gravity on another surface) and a solid (3-D) gravity anomaly defined in the fundamental gravimetric equation. Second, it introduces the ‘no topography’ gravity anomaly (which turns out to be the complete spherical Bouguer anomaly) as a means to generate a quantity that is smooth, thus suitable for gridding, and harmonic, thus suitable for downward continuation. It is understood that the possibility of downward continuing a smooth gravity anomaly would simplify the task of computing an accurate geoid. It is also shown that the planar Bouguer anomaly is not harmonic, and thus cannot be downward continued.
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high resolution grids of gravimetric terrain correction and complete Bouguer corrections over australia
Exploration Geophysics, 2002Co-Authors: Jon Kirby, Will FeatherstoneAbstract:Complete Bouguer corrections have been computed over the Australian mainland and Tasmania on a 9 arc-second grid (~250 m spatial resolution) from version 2 of the GEODATA digital elevation model (DEM) of Australia. These include the Bouguer plate correction to the geoid (mean sea level) and the planar terrain correction residual to this plate out to a radius of 50 km (beyond Hammer zone M). A constant topographic density of 2670 kg.m-3 has been used for both correction terms. The terrain corrections were computed using a planar two-dimensional fast Fourier transform (FFT) algorithm.
Aaron S Clark - One of the best experts on this subject based on the ideXlab platform.
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on the link between particle size and deviations from the beer lambert Bouguer law for direct transmission
Journal of Quantitative Spectroscopy & Radiative Transfer, 2014Co-Authors: Michael L Larsen, Aaron S ClarkAbstract:Abstract Ballistic photon models of radiative transfer in discrete absorbing random media have demonstrated deviations from the Beer–Lambert–Bouguer law of exponential attenuation. A number of theoretical constructs to quantify the deviation from the Beer–Lambert–Bouguer law have appeared in the literature, several of which rely principally on a statistical measure related to the statistics of the absorber spatial positions alone. Here, we utilize a simple computational model to explore the interplay between the geometric size of the absorbing obstacles and the statistics governing the placement of the absorbers in the volume. We find that a description of the volume that depends on particle size and the spatial statistics of absorbers is not sufficient to fully characterize deviations from the Beer–Lambert–Bouguer law. Implications for future further theoretical and computational explorations of the problem are explored.
János Kiss - One of the best experts on this subject based on the ideXlab platform.
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A Kárpát-Pannon Régió Bouguer-anomália térképének frekvenciatartománybeli vizsgálata és értelmezése | Investigation in spectral domain, and interpretation of Bouguer anomaly map of Carpathian-Pannonian Region
2020Co-Authors: János KissAbstract:Magyarorszag gravitacios Bouguer-anomaliaterkepenek egyik legerdekesebb Ny-rol K-re kinyilo tolcserszerű rajzolatat, a felszini foldtani ismereteink alapjan csak egyes reszleteiben tudjuk megmagyarazni. Minel tovabb nezzuk a terkepet (vizsgaljuk a Bouguer-anomaliateret), annal inkabb megbizonyosodunk rola, hogy valoszinűleg egy mely regionalis foldtani hatas tukroződik a felszinkozeli tektonika altal valtozatossa tett anomaliakep alatt. Ennek a hatasnak a jelenlete a Karpat-Pannon Regio Bouguer- anomaliaterkepen teljesen egyertelműen ott azonosithato, ahol ezek a jellegzetessegek (minimumzonak formajaban) a Pannon- medence kiterjedt gravitacios maximumat feldaraboljak. Tulajdonkeppen a Pannon-medence izosztatikus eredetű gravitacios maximumat irjak felul, jelentős minimumokat rajzolva Bouguer-anomaliaterkepre. Ezek a minimumok medencealjzatnal melyebb, kereg- (vagy kopeny-) eredetű hatasoktol szarmaznak, amire nehany evtizedes modellezesi tapasztalatainkbol kovetkeztetunk. A regionalis gravitacios lineamensek kialakulasanak okait vizsgalva az izosztatikus gyokerzonak lehetseges hatasa tobbszor is előkerult. Az izosztatikus gyokerzonak es kopenykiemelkedesek vizsgalataink alapjan hatassal lehetnek a Karpat- Pannon Regio kereg–kopeny mozgasmodelljere is. One of the most interesting parts of Bouguer anomaly map of Hungary is the cone form opening from West to East which can be explained by our surface geological knowledge only to a certain extent. The longer we are looking the map (studying the Bouguer anomaly fi eld) the more convinced we become that the effect of a deep regional geological structure is refl ected on the Bouguer anomaly map which gets variety from the near surface tectonics. These signatures can be identifi ed only on the Bouguer anomaly map of Carpathian-Pannonian Region where these minimum zones spaded the spacious gravity maximum of the Pannonian Basin. They overwrite the effect of isostasy generating signifi cant minimum zones on this gravity maximum. Based on our interpretation practice of several decades, we suppose that the source of these effects is deeper than the surface of the basement and it has a crust or mantle origin. Looking for the sources of regional gravity minimum zones (lineaments), we had to build the consequences of the isostasy into the geodynamical model. The presence of the isostatic roots below the mountain regions and antiroots below the deep basins can modify the crust (mantle) mobility in the Carpathian-Pannonian Region.
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Magyarország Bouguer-anomália térképének frekvenciatartománybeli vizsgálata és értelmezése = Investigation of spectral domain, and interpretation of Bouguer anomaly map of Hungary
2020Co-Authors: János KissAbstract:Ez a harmadik cikkunk a ketdimenzios spektralanalizis temakoreben. Most a magyarorszagi gravitacios Bougueranomaliaterkepet vizsgaljuk. A Magyar Geofi zika.ban kozolt egyik előző cikkben a Karpat-Pannon terseg teruletet, azaz az orszaghatarokon atnyulo Bouguer-anomaliaterkepet elemeztuk, s ott fi gyeltunk fel azokra a Pannon-medenceben jelentkező szeles minimumzonakra, amelyeket mely nyirasi zonakkent ertelmeztunk. Ezek a zonak a Pannon-medence egysegesnek tűnő gravitacios (izosztatikus eredetű) maximumat daraboljak fel. Az orszaghataron belul joval sűrűbb gravitacios adatrendszer all rendelkezesunkre, igy reszben a korabbi feldolgozasok ellenőrzesekent, reszben uj foldtani informaciok szerzesenek remenyeben spektralanalizist vegeztunk a magyarorszagi 385 000 meresi pontot meghalado, sűrűbb gravitacios adatrendszeren is. A Bouguer-anomaliaterkep vizsgalata kulonboző melysegekhez tartozo anomaliaterkepek egyedi elemzesevel szerkezetkutatasi szempontbol lehet erdekes, illetve megmutathatja az elterő melysegek sűrűsegeloszlasa alapjan a kulonboző keregvagy medencetipus-teruleteket. This is our third paper in the theme of spectral analysis. Our subject of investigation in this case is the Hungarian Bouguer anomaly map. In a previous paper published in Hungarian Geophysics, we studied the signatures of Bouguer anomaly map of Carpathian- Pannonian Region, and we determined wide minimum zones across Pannonian Basin interpreted by us as deep shear zones. These minimum zones spaded the spacious gravity maximum of the Pannonian Basin overwriting the effect of isostasy. The Hungarian gravity dataset including more than 385.000 stations has a better spatial resolution of gravity fi eld than the previous dataset of Carpathian-Pannonian Region. We studied this dataset by spectral analysis, too: 1) to check the previous result, and 2) to get new geological information. The depth slicing of Bouguer anomaly map and the interpretation of different fi ltered maps can be useful from point of view of structural geology. Different utility areas (crustal and basement blocks) can be interpreted using the supposed density distribution of the depth-sliced Bouguer anomaly maps.
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Bouguer anomaly map of hungary
2006Co-Authors: János KissAbstract:The Bouguer anomaly map of Hungary on a scale of 1:500,000 is given as Encloure 2. The main stages in construction and some geophysical–geological viewpoints are given.
