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The construction of sound speed field based on back propagation neural network in the global ocean / Junting Wang in Marine geodesy, vol 43 n° 6 (November 2020)
[article]
Titre : The construction of sound speed field based on back propagation neural network in the global ocean Type de document : Article/Communication Auteurs : Junting Wang, Auteur ; Tianhe Xu, Auteur ; Wenfeng Nie, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : pp 621 - 642 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] fonction orthogonale
[Termes IGN] interpolation spatiale
[Termes IGN] milieu marin
[Termes IGN] onde acoustique
[Termes IGN] propagation du son
[Termes IGN] réseau neuronal artificiel
[Termes IGN] salinité
[Termes IGN] sondage acoustique
[Termes IGN] température
[Termes IGN] vitesseRésumé : (auteur) The sound speed is a key parameter that affects the underwater acoustic positioning and navigation. Aiming at the high-precision construction of sound speed field in the complex marine environment, this paper proposes a sound speed field model based on back propagation neural network (BPNN) by considering the correlation of learning samples. The method firstly uses measured ocean parameters to construct the temperature and salinity field. Then the spatial position, the temperature and the salinity information are used to construct the global ocean sound speed field based on the back propagation neural network algorithm. During the processing, the learning samples of back propagation neural network are selected based on the correlation between sound speed and distance. The proposed algorithm is validated by the global Argo data as well as compared with the spatial interpolation and the empirical orthogonal function (EOF) algorithm. The results demonstrate that the average root mean squares of the BPNN considering the correlation of learning samples is 0.352 m/s compared to the 1.527 m/s of EOF construction and the 2.661 m/s of spatial interpolation, with an improvement of 76.9% and 86.8%. Therefore, the proposed algorithm can improve the construction accuracy of sound speed field in the complex marine environment. Numéro de notice : A2020-694 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01490419.2020.1815912 Date de publication en ligne : 14/09/2020 En ligne : https://doi.org/10.1080/01490419.2020.1815912 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96242
in Marine geodesy > vol 43 n° 6 (November 2020) . - pp 621 - 642[article]Boreal peatland forests: ditch network maintenance effort and water protection in a forest rotation framework / Jenny Miettinen in Canadian Journal of Forest Research, vol 50 n° 10 (October 2020)
[article]
Titre : Boreal peatland forests: ditch network maintenance effort and water protection in a forest rotation framework Type de document : Article/Communication Auteurs : Jenny Miettinen, Auteur ; Markku Ollikainen, Auteur ; Jukka Arovilita, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : pp 1025 – 1038 Note générale : bibliographie Langues : Français (fre) Anglais (eng) Descripteur : [Termes IGN] aménagement forestier
[Termes IGN] entretien du réseau
[Termes IGN] Finlande
[Termes IGN] forêt boréale
[Termes IGN] forêt équienne
[Termes IGN] nutriment végétal
[Termes IGN] protection des eaux
[Termes IGN] réseau de drainage
[Termes IGN] sédiment
[Termes IGN] tourbière
[Vedettes matières IGN] SylvicultureRésumé : (auteur) Ditch network maintenance promotes forest growth in drained peatland forests but increases nutrient and sediment loads, which are detrimental to water quality. Society needs to balance the harvest revenue from improved forest growth against deteriorating water quality. We examine socially optimal even-aged forest management in drained peatlands when harvesting and ditch network maintenance cause nutrient and sediment loading. The means to reduce loading include establishing overland flow fields and abstaining from ditch network maintenance. We characterize this choice analytically in a rotation framework and examine, in a numerical model, the key factors affecting the choice of forest management and water protection measures. We choose a drained peatland forest site located in northeastern Finland in the vicinity of ecologically vulnerable forest headwater streams. On the given drained forest site, we find a set of parameters under which implementing ditch network maintenance is privately but not socially optimal. Numéro de notice : A2020-745 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1139/cjfr-2019-0339 Date de publication en ligne : 28/08/2020 En ligne : https://doi.org/10.1139/cjfr-2019-0339 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96389
in Canadian Journal of Forest Research > vol 50 n° 10 (October 2020) . - pp 1025 – 1038[article]Challenges in flood modeling over data-scarce regions: how to exploit globally available soil moisture products to estimate antecedent soil wetness conditions in Morocco / El Mahdi El Khalk in Natural Hazards and Earth System Sciences, vol 20 n° 10 (October 2020)
[article]
Titre : Challenges in flood modeling over data-scarce regions: how to exploit globally available soil moisture products to estimate antecedent soil wetness conditions in Morocco Type de document : Article/Communication Auteurs : El Mahdi El Khalk, Auteur ; Yves Tramblay, Auteur ; Christian Massari, Auteur Année de publication : 2020 Article en page(s) : pp 2591 - 2607 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] Advanced scatterometer
[Termes IGN] Atlas marocain
[Termes IGN] bassin hydrographique
[Termes IGN] crue
[Termes IGN] humidité du sol
[Termes IGN] image SMOS
[Termes IGN] inondation
[Termes IGN] Maroc
[Termes IGN] modèle hydrographique
[Termes IGN] modélisation
[Termes IGN] variation saisonnière
[Termes IGN] zone semi-arideRésumé : (auteur) The Mediterranean region is characterized by intense rainfall events giving rise to devastating floods. In Maghreb countries such as Morocco, there is a strong need for forecasting systems to reduce the impacts of floods. The development of such a system in the case of ungauged catchments is complicated, but remote-sensing products could overcome the lack of in situ measurements. The soil moisture content can strongly modulate the magnitude of flood events and consequently is a crucial parameter to take into account for flood modeling. In this study, different soil moisture products (European Space Agency Climate Change Initiative, ESA-CCI; Soil Moisture and Ocean Salinity, SMOS; Soil Moisture and Ocean Salinity by the Institut National de la Recherche Agronomique and Centre d'Etudes Spatiales de la Biosphère, SMOS-IC; Advanced Scatterometer, ASCAT; and ERA5 reanalysis) are compared to in situ measurements and one continuous soil-moisture-accounting (SMA) model for basins located in the High Atlas Mountains, upstream of the city of Marrakech. The results show that the SMOS-IC satellite product and the ERA5 reanalysis are best correlated with observed soil moisture and with the SMA model outputs. The different soil moisture datasets were also compared to estimate the initial soil moisture condition for an event-based hydrological model based on the Soil Conservation Service curve number (SCS-CN). The ASCAT, SMOS-IC, and ERA5 products performed equally well in validation to simulate floods, outperforming daily in situ soil moisture measurements that may not be representative of the whole catchment soil moisture conditions. The results also indicated that the daily time step may not fully represent the saturation state before a flood event due to the rapid decay of soil moisture after rainfall in these semiarid environments. Indeed, at the hourly time step, ERA5 and in situ measurements were found to better represent the initial soil moisture conditions of the SCS-CN model by comparison with the daily time step. The results of this work could be used to implement efficient flood modeling and forecasting systems in semiarid regions where soil moisture measurements are lacking. Numéro de notice : A2020-610 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.5194/nhess-20-2591-2020 Date de publication en ligne : 05/10/2020 En ligne : https://doi.org/10.5194/nhess-20-2591-2020 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95974
in Natural Hazards and Earth System Sciences > vol 20 n° 10 (October 2020) . - pp 2591 - 2607[article]Mapping wetland using the object-based stacked generalization method based on multi-temporal optical and SAR data / Yaotong Cai in International journal of applied Earth observation and geoinformation, vol 92 (October 2020)
[article]
Titre : Mapping wetland using the object-based stacked generalization method based on multi-temporal optical and SAR data Type de document : Article/Communication Auteurs : Yaotong Cai, Auteur ; Xinyu Li, Auteur ; Meng Zhang, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : n° 102164 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image mixte
[Termes IGN] algorithme de généralisation
[Termes IGN] analyse d'image orientée objet
[Termes IGN] cartographie thématique
[Termes IGN] Chine
[Termes IGN] filtre de déchatoiement
[Termes IGN] image radar moirée
[Termes IGN] image Sentinel-MSI
[Termes IGN] image Sentinel-SAR
[Termes IGN] modélisation spatio-temporelle
[Termes IGN] Normalized Difference Vegetation Index
[Termes IGN] prairie
[Termes IGN] rétrodiffusion
[Termes IGN] série temporelle
[Termes IGN] zone humideRésumé : (auteur) Wetland ecosystems have experienced dramatic challenges in the past few decades due to natural and human factors. Wetland maps are essential for the conservation and management of terrestrial ecosystems. This study is to obtain an accurate wetland map using an object-based stacked generalization (Stacking) method on the basis of multi-temporal Sentinel-1 and Sentinel-2 data. Firstly, the Robust Adaptive Spatial Temporal Fusion Model (RASTFM) is used to get time series Sentinel-2 NDVI, from which the vegetation phenology variables are derived by the threshold method. Subsequently, both vertical transmit-vertical receive (VV) and vertical transmit-horizontal receive (VH) polarization backscatters (σ0 VV, σ0 VH) are obtained using the time series Sentinel-1 images. Speckle noise inherent in SAR data, resulting in over-segmentation or under-segmentation, can affect image segmentation and degrade the accuracies of wetland classification. Therefore, we segment Sentinel-2 multispectral images to delineate meaningful objects in this study. Then, in order to reduce data redundancy and computation time, we analyze the optimal feature combination using the Sentinel-2 multispectral images, Sentinel-2 NDVI time series, phenological variables and other vegetation index derived from Sentinel-2 multispectral images, as well as time series Sentinel-1 backscatters at the object level. Finally, the stacked generalization algorithm is utilized to extract the wetland information based on the optimal feature combination in the Dongting Lake wetland. The overall accuracy and Kappa coefficient of the object-based stacked generalization method are 92.46% and 0.92, which are 3.88% and 0.04 higher than that using the pixel-based method. Moreover, the object-based stacked generalization algorithm is superior to single classifiers in classifying vegetation of high heterogeneity areas. Numéro de notice : A2020-748 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1016/j.jag.2020.102164 Date de publication en ligne : 07/06/2020 En ligne : https://doi.org/10.1016/j.jag.2020.102164 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96398
in International journal of applied Earth observation and geoinformation > vol 92 (October 2020) . - n° 102164[article]Uncertainty of forested wetland maps derived from aerial photography / Stephen P. Prisley in Photogrammetric Engineering & Remote Sensing, PERS, vol 86 n° 10 (October 2020)
[article]
Titre : Uncertainty of forested wetland maps derived from aerial photography Type de document : Article/Communication Auteurs : Stephen P. Prisley, Auteur ; Jeffery A. Turner, Auteur ; Mark J. Brown, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : pp 609 - 617 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse spatio-temporelle
[Termes IGN] carte forestière
[Termes IGN] changement d'utilisation du sol
[Termes IGN] délimitation
[Termes IGN] détection de changement
[Termes IGN] Etats-Unis
[Termes IGN] image aérienne
[Termes IGN] incertitude des données
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] précision de la classification
[Termes IGN] zone humideRésumé : (Auteur) Forested wetlands (FWs) are economically and environmentally important, so monitoring of change is done using remote sensing by several U.S. federal programs. To better understand classification and delineation uncertainties in FW maps, we assessed agreement between National Wetlands Inventory maps based on aerial photography and field determinations at over 16 000 Forest Inventory and Analysis plots. Analyses included evaluation of temporal differences and spatial uncertainty in plot locations and wetland boundaries. User's accuracy for the wetlands map was 90% for FW and 68% for nonforested wetlands. High levels of false negatives were observed, with less than 40% of field-identified wetland plots mapped as such. Epsilon band analysis indicated that if delineation of FW boundaries in the southeastern U.S. met the data quality standards (5 meters), then the area within uncertainty bounds accounts for 15% to 30% of estimated FW area. Numéro de notice : A2020-492 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.14358/PERS.86.10.609 Date de publication en ligne : 01/10/2020 En ligne : https://doi.org/10.14358/PERS.86.10.609 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96092
in Photogrammetric Engineering & Remote Sensing, PERS > vol 86 n° 10 (October 2020) . - pp 609 - 617[article]Exemplaires(1)
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