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Forest above ground biomass inversion by fusing GLAS with optical remote sensing data / Xiaohuan Xi in ISPRS International journal of geo-information, vol 5 n° 4 (April 2016)
[article]
Titre : Forest above ground biomass inversion by fusing GLAS with optical remote sensing data Type de document : Article/Communication Auteurs : Xiaohuan Xi, Auteur ; Tingting Han, Auteur ; Cheng Wang, Auteur ; et al., Auteur Année de publication : 2016 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] biomasse aérienne
[Termes IGN] classification par réseau neuronal
[Termes IGN] distribution du coefficient de réflexion bidirectionnelle BRDF
[Termes IGN] données ICEsat
[Termes IGN] forêt
[Termes IGN] hauteur de la végétation
[Termes IGN] image Landsat-TM
[Termes IGN] image optique
[Termes IGN] image Terra-MODIS
[Termes IGN] Leaf Area Index
[Termes IGN] MNS ASTER
[Termes IGN] régression
[Termes IGN] Yunnan (Chine)Résumé : (auteur) Forest biomass is an important parameter for quantifying and understanding biological and physical processes on the Earth’s surface. Rapid, reliable, and objective estimations of forest biomass are essential to terrestrial ecosystem research. The Geoscience Laser Altimeter System (GLAS) produced substantial scientific data for detecting the vegetation structure at the footprint level. This study combined GLAS data with MODIS/BRDF (Bidirectional Reflectance Distribution Function) and ASTER GDEM data to estimate forest aboveground biomass (AGB) in Xishuangbanna, Yunnan Province, China. The GLAS waveform characteristic parameters were extracted using the wavelet method. The ASTER DEM was used to compute the terrain index for reducing the topographic influence on the GLAS canopy height estimation. A neural network method was applied to assimilate the MODIS BRDF data with the canopy heights for estimating continuous forest heights. Forest leaf area indices (LAIs) were derived from Landsat TM imagery. A series of biomass estimation models were developed and validated using regression analyses between field-estimated biomass, canopy height, and LAI. The GLAS-derived canopy heights in Xishuangbanna correlated well with the field-estimated AGB (R2 = 0.61, RMSE = 52.79 Mg/ha). Combining the GLAS estimated canopy heights and LAI yielded a stronger correlation with the field-estimated AGB (R2 = 0.73, RMSE = 38.20 Mg/ha), which indicates that the accuracy of the estimated biomass in complex terrains can be improved significantly by integrating GLAS and optical remote sensing data. Numéro de notice : A2016-820 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/ijgi5040045 En ligne : https://doi.org/10.3390/ijgi5040045 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82625
in ISPRS International journal of geo-information > vol 5 n° 4 (April 2016)[article]Use of GIS-supported comparative cartography and historical maps in long-term forest cover changes analysis in the Holy cross mountains (Poland) / Tadeusz Ciupa in Baltic forestry, vol 22 n° 1 ([01/02/2016])
[article]
Titre : Use of GIS-supported comparative cartography and historical maps in long-term forest cover changes analysis in the Holy cross mountains (Poland) Type de document : Article/Communication Auteurs : Tadeusz Ciupa, Auteur ; Roman Suligowski, Auteur ; Grzegorz Walek, Auteur Année de publication : 2016 Article en page(s) : pp 63 - 73 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG
[Termes IGN] analyse comparative
[Termes IGN] analyse diachronique
[Termes IGN] carte thématique
[Termes IGN] couvert forestier
[Termes IGN] dix-neuvième siècle
[Termes IGN] géoréférencement
[Termes IGN] MNS SRTM
[Termes IGN] Pologne
[Termes IGN] vectorisation
[Termes IGN] vingtième siècleRésumé : (auteur) In recent years, forest research benefits from access to archived cartographic materials and geographic information systems technology, which both allow to analyze the processes of forest cover changes over time. Available digital elevation models (DEMs) and soil maps make it possible to consider terrain relief and soils characteristics in the research. The present paper analyzes changes of forest cover in the Holy Cross Mountains (central Poland) within the period of 1800–2011 and they relation to altitude and slope gradient classes as well as to genetic soil groups. The source materials consist of topographic maps created in 1800, 1900, 1930, 1983 and thematic maps: Polish Sozological Map in 1: 50,000 scale from 2011, Soil Map of Poland in 1: 300,000 scale and SRTM3 digital elevation model. Scanned maps were georeferenced to metric coordinate system and then forest areas were digitalized by on-screen vectorization. Digital elevation model was used to delineate elevation and slope gradient classes. Finally, the overlay geoprocessing methods were used to analyze the areas of forest cover changes in time, also in addition to altitude zones, slope gradient and genetic soil type classes. Forest cover indicator (%) and mean annual index of forest cover change (ha•year-1) have been calculated. Forest cover was the highest at the beginning of the study period in 1800 and the lowest in 1930. The decrease in forest cover in this period equaled 35.3 %. A slow process of recovery began in 1930 and continues till today. However, the coverage noted in 1800 has not yet been achieved. Also forest cover stability analysis has been performed. Today forest areas of very high stability cover about 21% of the Holy Cross Mountains and 49% of the area covered by trees in 1800. The present analysis has been performed with the use of GIS-supported comparative cartography and historical maps, which have significantly improved the investigations of long-term forest cover changes. Numéro de notice : A2016--097 Affiliation des auteurs : non IGN Thématique : FORET/GEOMATIQUE Nature : Article DOI : sans En ligne : https://www.balticforestry.mi.lt/bf/PDF_Articles/2016-22%5b1%5d/e-Baltic%20Fores [...] Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84650
in Baltic forestry > vol 22 n° 1 [01/02/2016] . - pp 63 - 73[article]High-resolution forest canopy height estimation in an African blue carbon ecosystem / David Lagomasino in Remote sensing in ecology and conservation, vol 1 n° 1 (October 2015)
[article]
Titre : High-resolution forest canopy height estimation in an African blue carbon ecosystem Type de document : Article/Communication Auteurs : David Lagomasino, Auteur ; Temilola Fatoyinbo, Auteur ; Seung-Kuk Lee, Auteur ; Marc Simard, Auteur Année de publication : 2015 Article en page(s) : pp 51 - 60 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques
[Termes IGN] biomasse
[Termes IGN] données localisées 3D
[Termes IGN] estimation statistique
[Termes IGN] hauteur des arbres
[Termes IGN] mangrove
[Termes IGN] MNS SRTM
[Termes IGN] MozambiqueRésumé : (auteur) Mangrove forests are one of the most productive and carbon dense ecosystems that are only found at tidally inundated coastal areas. Forest canopy height is an important measure for modeling carbon and biomass dynamics, as well as land cover change. By taking advantage of the flat terrain and dense canopy cover, the present study derived digital surface models (DSMs) using stereo-photogrammetric techniques on high-resolution spaceborne imagery (HRSI) for southern Mozambique. A mean-weighted ground surface elevation factor was subtracted from the HRSI DSM to accurately estimate the canopy height in mangrove forests in southern Mozambique. The mean and H100 tree height measured in both the field and with the digital canopy model provided the most accurate results with a vertical error of 1.18-1.84 m, respectively. Distinct patterns were identified in the HRSI canopy height map that could not be discerned from coarse shuttle radar topography mission canopy maps even though the mode and distribution of canopy heights were similar over the same area. Through further investigation, HRSI DSMs have the potential of providing a new type of three-dimensional dataset that could serve as calibration/validation data for other DSMs generated from spaceborne datasets with much larger global coverage. HSRI DSMs could be used in lieu of Lidar acquisitions for canopy height and forest biomass estimation, and be combined with passive optical data to improve land cover classifications. Numéro de notice : A2015--101 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.1002/rse2.3 En ligne : http://doi.org/10.1002/rse2.3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=87170
in Remote sensing in ecology and conservation > vol 1 n° 1 (October 2015) . - pp 51 - 60[article]Documents numériques
en open access
High-resolution forest canopy height estimation - pdf éditeurAdobe Acrobat PDF GIS based drainage morphometry and its influence on hydrology in parts of Western Ghats region, Maharashtra, India / Dipak R. Samal in Geocarto international, vol 30 n° 7 - 8 (August - September 2015)
[article]
Titre : GIS based drainage morphometry and its influence on hydrology in parts of Western Ghats region, Maharashtra, India Type de document : Article/Communication Auteurs : Dipak R. Samal, Auteur ; Shirish S. Gedam, Auteur ; R. Nagarajan, Auteur Année de publication : 2015 Article en page(s) : pp 755 - 778 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG
[Termes IGN] analyse multicritère
[Termes IGN] base de données thématiques
[Termes IGN] bassin hydrographique
[Termes IGN] carte topographique
[Termes IGN] corrélation
[Termes IGN] géomorphométrie
[Termes IGN] Ghats occidentaux
[Termes IGN] hydrographie de surface
[Termes IGN] Inde
[Termes IGN] intégration de données
[Termes IGN] Maharashtra (Inde ; état)
[Termes IGN] matrice
[Termes IGN] MNS ASTER
[Termes IGN] système d'information géographiqueRésumé : (Auteur) Various drainage morphometric parameters in the Upper Bhima river basin and its influence on hydrological processes (e.g. runoff, peak flow, time to peak, infiltration, overland flow, etc.) were discussed using geographical information system (GIS) and remote sensing techniques. Survey of India topographical maps and ASTER digital elevation model was incorporated for thematic database generation and morphometric parameter evaluation in GIS environment. The whole study basin was divided into 8 sub-basins so that the spatial variation of morphological parameters and its influence on hydrology could be analyzed. The interrelationship between morphometric variables were computed (p Numéro de notice : A2015-501 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2014.978903 Date de publication en ligne : 15/06/2015 En ligne : http://www.tandfonline.com/doi/full/10.1080/10106049.2014.978903 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77417
in Geocarto international > vol 30 n° 7 - 8 (August - September 2015) . - pp 755 - 778[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 059-2015041 RAB Revue Centre de documentation En réserve L003 Disponible Depth, anisotropy, and water equivalent of snow estimated by radar interferometry and polarimetry / Silvan Leinss (2015)
Titre : Depth, anisotropy, and water equivalent of snow estimated by radar interferometry and polarimetry Type de document : Thèse/HDR Auteurs : Silvan Leinss, Auteur Editeur : Zurich : Eidgenossische Technische Hochschule ETH - Ecole Polytechnique Fédérale de Zurich EPFZ Année de publication : 2015 Collection : Dissertationen ETH num. 23093 Importance : 243 p. Format : 21 x 30 cm Note générale : bibliographie
A thesis submitted to attain the degree of doctor of sciences of ETH ZurichLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] anisotropie
[Termes IGN] image TerraSAR-X
[Termes IGN] interféromètrie par radar à antenne synthétique
[Termes IGN] MNS TerraSAR & TanDEM-X
[Termes IGN] neige
[Termes IGN] polarimétrie radarRésumé : (auteur) Snow contributes to the water supply of almost one-sixth of the world's population and has a strong influence on the energy balance of the earth. Snow provides water for life but also threatens life in the form of avalanches and flooding due to snow melt. Most of the world's snow cover is located in remote and inaccessible regions, therefore large-scale snow monitoring is only possible with remote sensing techniques. In the entire electromagnetic spectrum, ranging from kilometer long radio waves to ultrashort gamma waves, only three atmospheric spectral windows exit through which satellites can observe the surface of the earth. Two of them, the optical and the infrared window, are often blocked by clouds or atmospheric water vapor. Visible or infrared light, which is reflected at the snow surface, is difficult to be used for derivation of any volumetric information of the snow pack. Active and passive microwave systems, which operate in the radio window, have the potential to obtain volumetric information of snow because microwaves can penetrate the snow cover. The aim of this thesis is to determine snow properties, like snow depth, snow anisotropy, and snow water equivalent, by analyzing phase differences of radar signals reflected from snow covered regions. Current radar systems provide not only the backscatter intensity of an object, but also an object-specific scattering phase. The phase contains information about object properties as well as accurate information about the propagation delay time. In this thesis, phase differences resulting from propagation delays are analyzed with respect to different polarizations, observation times and observation geometries. Based on polarimetric phase differences, a method to determine the depth of fresh snow was developed. The copolar phase difference (CPD) obtained from radar images acquired with vertically and horizontally polarized microwaves by the satellites TerraSAR-X and TanDEM-X were analyzed. Positive phase differences could be explained by a horizontal anisotropy in fresh snow, which results from snow settling. As the phase difference is a volumetric property, the magnitude of the phase difference is roughly proportional to the depth of fresh snow. The validation with snow depth measurements on the ground show that the spatial variability of the depth of fresh snow can be determined with a resolution below 100 m with space-borne sensors like TerraSAR-X. Cold temperatures have been found to decrease observed phase differences due to temperature gradient metamorphism. The observed relation between the CPD and fresh snow, snow settling, and temperature gradient metamorphism provides a contact-less and destruction-free tool to observe the anisotropy, which is a metamorphic state of snow. The measurable dielectric anisotropy is directly linked to the structural anisotropy of snow which is responsible for the mechanical stability as well as the thermal conductivity of the snow pack. This makes the anisotropy relevant for the energy balance of snow and snow covered soil. In order to measure the anisotropy, a rigorous electromagnetic model was developed which provides a parameter free link between three-dimensional two-point correlation functions of the microstructure of snow, the effective permittivity tensor, and the macroscopically measured copolar phase difference. For verification of the model, four years of ground-based radar data, acquired by the SnowScat instrument in Sodankylä, Finland, were analyzed with respect to the frequency and incidence angle dependence of the copolar phase. Computer tomography data were used for validation of the anisotropy determined from the copolar phase difference measured by SnowScat. The unique dataset of the currently longest time series of anisotropy measurements provides a new basis for improvement of existing snow models. Four years of anisotropy data were used to develop and validate a thermodynamic snow model based on meteorological input data. The model consists of three terms which describe snow settling, temperature gradient metamorphism, and relaxation based on isotropic water vapor transport. The model was calibrated by balancing the three terms in order to reproduce the measured anisotropy time series. The results of the model, vertically resolved anisotropy pro les of the snow pack, were validated with anisotropy pro les determined by computer tomography. In comparison to the anisotropy, which determines specific properties of the snow volume, the snow water equivalent (SWE) determines how much water is stored in the snow pack. Differential interferometry, where the phase difference of two radar acquisitions separated by a certain time is analyzed, is a promising tool to determine SWE. However, temporal decorrelation of the phase signal is a major drawback of this technique. A decorrelation time of a few days has been observed in space-borne acquisitions from TerraSAR-X which prevents any successful SWE determination. However, using SnowScat as a ground based radar interferometer, it was possible for the first time to measure the accumulation of SWE during four entire winter seasons. A multi-frequency phase unwrapping technique was used for reconstruction of phase wraps which occurred due to intense snow precipitation. The study was performed at exceptionally high frequencies in the X- and Ku-band and with a very high temporal resolution of only 4 hours. The successful demonstration of differential interferometry to determine SWE raises hope to apply the demonstrated technique on data of future radar satellites which operate at longer repeat times of a few days and lower frequencies of a few GHz. Both methods, the CPD analysis as well as differential interferometry, cannot be vi applied for wet snow. Microwave penetration into wet snow is generally small and most of the reflected energy results from scattering at the snow surface. This is interesting for single-pass SAR interferometry, where phase differences are compared, which are measured by two SAR-sensors which simultaneously observe the same scene with slightly different angles. Single-pass SAR interferometry can provide accurate surface models at a horizontal resolution of a few meters. The difference between two digital elevation models (DEM), one obtained during snow free conditions and one obtained during the onset of snow melt, can therefore provide direct information about snow depth. DEM differencing was applied on TanDEM-X acquisitions from spring and autumn and snow depths maps were obtained which agree with the snow- depth-maps provided by the Institute for Snow and Avalanche Research, SLF. A key requirement for successful snow depth estimation is that the snow surface can be recognized as wet. As the backscatter intensity decreases significantly during snow melt, wet snow detection is straight forward and the total accumulated snow depth of wet spring snow can be determined. This thesis shows that the analysis of the phase signal contained in radar acquisitions provides a broad spectrum of information about the snow pack. The developed method for anisotropy determination provides not only a unique opportunity to improve snow models, but also a method to globally sense the metamorphic state of snow. The currently longest radar-derived time series of SWE measurements raise hope to apply differential interferometry for global SWE determination of dry snow. The shown accuracy for snow depth determination from high frequency, interferometric, single-pass SAR systems demonstrates that such systems are important missions for monitoring changes in snow depth and ice thickness in remote alpine and polar regions in order monitor changes of the global distribution of fresh water stored in the form of ice or snow. Numéro de notice : 17199 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère Note de thèse : doctoral thesis : Sciences : ETH Zurich : 2015 En ligne : http://dx.doi.org/10.3929/ethz-a-010603517 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81170 Improved land cover mapping using aerial photographs and satellite images / Katalin Varga in Open geosciences, vol 7 n° 1 (January 2015)PermalinkTopographic correction of ALOS-PALSAR images using InSAR-derived DEM / Anup Das in Geocarto international, vol 30 n° 1 - 2 (January - February 2015)PermalinkEtude qualitative de la précision des modèles numériques de terrain globaux : cas de l'Algérie / M. Haddad in Bulletin des sciences géographiques, n° 29 (janvier - juin 2014)PermalinkEarthEnv-DEM90: A nearly-global, void-free, multi-scale smoothed, 90m digital elevation model from fused ASTER and SRTM data / Natalie Robinson in ISPRS Journal of photogrammetry and remote sensing, vol 87 (January 2014)PermalinkÉlaboration de la cartographie des échos du sol d’un radar météorologique à l’aide du modèle numérique de terrain (SRTM) / Abdenasser Djafri in Revue internationale de géomatique, vol 23 n° 2 (juin - aout 2013)PermalinkImproved topographic mapping through high-resolution SAR interferometry with atmospheric effect removal / Mingsheng Liao in ISPRS Journal of photogrammetry and remote sensing, vol 80 (June 2013)PermalinkFusion d'informations issue de la télédétection radar pour l'observation de déplacements dans la région de Manaus (Amazonie) / F.L. Ramos in Revue Française de Photogrammétrie et de Télédétection, n° 198 - 199 (Septembre 2012)PermalinkUtilisation des SIG pour la modélisation des réseaux hydrologiques et l'analyse spatiale des bassins versants du Sahel de Sfax / Nadia Trabelsi in Géomatique expert, n° 88 (01/09/2012)PermalinkRéduction du chatoiement et apport des données ASAR Envisat et MNE SRTM à la cartographie hydrostructurale du bassin côtier de l'Agnéby (Sud-Est de la côte d'Ivoire) / T. Assoma in Photo interprétation, European journal of applied remote sensing, vol 47 n° 4 (décembre 2011)PermalinkFusion de données topographiques pour la réalisation d'un modèle numérique de terrain : Application à la modélisation de la crue du Niger / Elodie Paris in XYZ, n° 128 (septembre - novembre 2011)Permalink