Relevant bibliographies by topics / Observations de terrain

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  2. Dissertations / Theses
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Academic literature on the topic 'Observations de terrain'

Author: Grafiati
Published: 8 February 2025

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Journal articles on the topic "Observations de terrain"

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Huang, Guosheng, Mingli Wu, Zhen Qiao, Songping Fu, Qiujiang Liu, Xiaowei Huai, and Pengcheng Yan. "Characteristics and Simulation of Icing Thickness of Overhead Transmission Lines across Various Micro-Terrains." Energies 17, no. 16 (August 14, 2024): 4024. http://dx.doi.org/10.3390/en17164024.

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The hazard of ice accretion on overhead power circuits is significant, yet predicting it is very difficult. The key reason lies in the shortage of sufficient observational data on ice thickness, and previous studies have also rarely taken into account micro-terrain and micro-meteorological conditions. In response to the challenge of simulating overhead line icing, this study introduces a new icing simulation technique that fully considers the effects of micro-terrain and micro-meteorology. For this technique, typical micro-terrains of overhead line areas are first identified by using high-resolution elevation data, and the icing thickness characteristics in different micro-terrains are analyzed. Subsequently, icing thickness simulations for different micro-terrains are conducted. The results indicate that during the icing process, the icing thickness ranges from 5 mm to 8 mm under three types of micro-terrain, namely, “uplift type”, “alpine drainage divide type” and “canyon wind channel type”, whereas the icing thickness is less than 5 mm in the “flat type” of micro-terrain. This finding suggests that the first three micro-terrain types facilitate icing on overhead transmission lines due to the condensation and uplifting effects of water vapor caused by terrain. However, flat terrain lacks the conditions necessary for water vapor accumulation and thus is not easy to form icing. The results are advantageous for the deployment of overhead power lines in intricate terrain. It is advisable to steer clear of regions susceptible to icing, and endeavor to install circuits in level territories whenever feasible. In addition, the simulated icing thickness under different terrains is in good agreement with the observations. Specifically, the correlation coefficient between simulated and observed icing thickness is significant at the 0.99 confidence level, and the deviations between them are within 0.5 mm. This signifies that the forecasting methodologies employed are dependable and possess significant implications as a reference for disaster prevention and mitigation efforts.
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Zhou, Fangrong, Xiaowei Huai, Pengcheng Yan, Cailing Zhao, Xingliang Jiang, Hao Pan, Yutang Ma, and Hao Geng. "Research on the Identification of Typical Terrain Patterns in Yunnan Province Based on the K-Means Technology." Atmosphere 15, no. 3 (February 20, 2024): 244. http://dx.doi.org/10.3390/atmos15030244.

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Wire icing is a prevalent challenge in both industrial and scientific domains, and it is widely acknowledged that terrain and water vapor are significant contributing factors in the formation of wire icing. Consequently, the identification of terrains that are prone to inducing water vapor uplift serves as the scientific foundation for predicting ice accumulation on power lines. Yunnan Province, a mountainous province in China, features a large elevation difference. In winter, this region is prone to wire, pole and tower icing, which can affect power transmission and cause economic and property losses. Therefore, it is necessary to conduct research on the identification of typical terrain patterns in this region. In previous terrain studies, more attention has been focused on slope and aspect, watershed analysis and terrain profile analysis. When the purpose of the terrain identification is to analyze which terrains are more prone to collecting water vapor, we hope to obtain slightly larger terrain blocks and analyze the water vapor sources for different terrains in order to identify typical terrains that are conducive to icing formation. A new technology for identifying terrain patterns based on the K-means clustering method is proposed in this study to explore the typical terrain in Yunnan province. Additionally, the influences of different terrain patterns on water vapor movement are also analyzed. The results indicate that the typical terrains in Yunnan are “Valley-Air Channel”, “Topographic Uplifting”, “Ravine”, “Mountain Pass” and “Alpine Divide” patterns. The results show that the identified typical terrain is consistent with observations from satellite images, which verifies the effectiveness of this identification method. Among these five typical terrains, the “Valley-Air Channel”, the “Topographic Uplifting” and the “Mountain Pass” terrains are prone to collecting water vapor and forming ice cover. The “Alpine Divide” terrain is also prone to accumulating water vapor on both sides to form ice cover. The identified typical terrain demonstrates that typical terrain patterns near water bodies are more prone to the occurrence of wire, pole and tower icing because these areas are abundant in water vapor, and the extensive water vapor is easily condensed under the effects of terrain uplifting and cooling. In these key areas, existing wires and towers, as well as those to be constructed in the future, deserve our special attention.
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Li, Hui, Lin Chen, Zhaoyang Wang, and Zhongdi Yu. "Mapping of River Terraces with Low-Cost UAS Based Structure-from-Motion Photogrammetry in a Complex Terrain Setting." Remote Sensing 11, no. 4 (February 24, 2019): 464. http://dx.doi.org/10.3390/rs11040464.

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River terraces are the principal geomorphic features for unraveling tectonics, sea level, and climate conditions during the evolutionary history of a river. The increasing availability of high-resolution topography data generated by low-cost Unmanned Aerial Systems (UAS) and modern photogrammetry offer an opportunity to identify and characterize these features. In this paper, we assessed the capabilities of UAS-based Structure-from-Motion (SfM) photogrammetry, coupled with a river terrace detection algorithm for mapping of river terraces over a 1.9 km2 valley of complex terrain setting, with a focus on the performance of this latest technology over such complex terrains. With the proposed image acquisition approach and SfM photogrammetry, we constructed a 3.8 cm resolution orthomosaic and digital surface model (DSM). The vertical accuracy of DSM was assessed against 196 independent checkpoints measured with a real-time kinematic (RTK) GPS. The results indicated that the root mean square error (RMSE) and mean absolute error (MAE) were 3.1 cm and 2.9 cm, respectively. These encouraging results suggest that this low-cost, logistically simple method can deliver high-quality terrain datasets even in the complex terrain, competitive with those obtained using more expensive laser scanning. A simple algorithm was then employed to detect river terraces from the generated DSM. The results showed that three levels of river terraces and a high-level floodplain were identified. Most of the detected river terraces were confirmed by field observations. Despite the highly erosive nature of fluvial systems, this work obtained good results, allowing fast analysis of fluvial valleys and their comparison. Overall, our results demonstrated that the low-cost UAS-based SfM technique could yield highly accurate ultrahigh-resolution topography data over complex terrain settings, making it particularly suitable for quick and cost-effective mapping of micro to medium-sized geomorphic features under such terrains in remote or poorly accessible areas. Methods discussed in this paper can also be applied to produce highly accurate digital terrain data over large spatial extents for some other places of complex terrains.
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Wiersema, David J., Katherine A. Lundquist, and Fotini Katopodes Chow. "Mesoscale to Microscale Simulations over Complex Terrain with the Immersed Boundary Method in the Weather Research and Forecasting Model." Monthly Weather Review 148, no. 2 (January 8, 2020): 577–95. http://dx.doi.org/10.1175/mwr-d-19-0071.1.

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Abstract Improvements to the Weather Research and Forecasting (WRF) Model are made to enable multiscale simulations over highly complex terrain with dynamically downscaled boundary conditions from the mesoscale to the microscale. Over steep terrain, the WRF Model develops numerical errors that are due to grid deformation of the terrain-following coordinates. An alternative coordinate system, the immersed boundary method (IBM), has been implemented into WRF, allowing for simulations over highly complex terrain; however, the new coordinate system precluded nesting within mesoscale simulations using WRF’s native terrain-following coordinates. Here, the immersed boundary method and WRF’s grid-nesting framework are modified to seamlessly work together. This improved framework for the first time allows for large-eddy simulation over complex (urban) terrain with IBM to be nested within a typical mesoscale WRF simulation. Simulations of the Joint Urban 2003 field campaign in Oklahoma City, Oklahoma, are performed using a multiscale five-domain nested configuration, spanning horizontal grid resolutions from 6 km to 2 m. These are compared with microscale-only simulations with idealized lateral boundary conditions and with observations of wind speed/direction and SF6 concentrations from a controlled release from intensive observation period 3. The multiscale simulation, which is configured independent of local observations, shows similar model skill predicting wind speed/direction and improved skill predicting SF6 concentrations when compared with the idealized simulations, which require use of observations to set mean flow conditions. Use of this improved multiscale framework shows promise for enabling large-eddy simulation over highly complex terrain with dynamically downscaled boundary conditions from mesoscale models.
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ORDONEZ, JUAN, and CAMILO ORDONEZ. "ROBOTIC LEGS DESIGN – CONSTRUCTAL CONSIDERATIONS." 14th CONSTRUCTAL LAW CONFERENCE | 10-11 October 2024, Bucharest, Romania 2024, no. 1 (December 18, 2024): 109–12. https://doi.org/10.59277/clc.2024.28.

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In robotic navigation, wheels are highly efficient for engineered surfaces. However, they need to be more efficient when navigating over rough terrains. Evolution has resulted in limbed creatures that are highly adapted to extreme terrains. This paper explores the design of robotic legs for sagittal motion in uneven terrains. The paper builds upon locomotion theories to identify geometrical features of the leg and groups of legs as a function of terrain features. The predictions of the analytical models are compared against observations in the animal kingdom. The study is focused on legs that can be represented with two degrees of freedom, connected via revolute joints. It uses simplified terrain features and reduced-order dynamic models to evaluate the cost of transport associated with the different legs and terrain configurations. Examples of animal and animal-inspired robots to which the model applies include crabs, horses, and some insects. The model is expected to help design more agile robots and be extensible to designing human prostheses and end effectors for robotic manipulators.
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Liu, Peiting, Zhifang Xu, Jiandong Gong, and Wei Chen. "A New Progressive EOFs Quality Control Method for Surface Pressure Data Based on the Barometric Height and Biweight Average Correction." Atmosphere 14, no. 6 (June 15, 2023): 1032. http://dx.doi.org/10.3390/atmos14061032.

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When assimilating surface pressure data in synoptic-scale models, we find the utilization rate of surface pressure data in zones with complex terrains is not high. Therefore, it is particularly important and urgent to carry out quality control of surface pressure data. Numerical weather prediction model analysis and forecasting provide essential data that can be compared with surface observations. The main adverse effects on surface pressure quality control include elevation differences between the model terrain and the observation stations and continuous outliers with the same characteristics in the initiation stage of quality control. Therefore, we propose a progressive empirical orthogonal function (EOF) with simulated observation (EOFs) combining barometric height correction (BHC) and biweight average correction (BAC) methods for the quality control of surface pressure data in this study. From the quality control results of the surface pressure data in regions with complex topography in China during June–August 2013, it was found that the BHC method could effectively reduce the deviations caused by elevation differences between the model terrain and the observation stations, and the BAC method could obviously reduce systematic deviations due to physical processes and the parameterization schemes of the models. The BHC-BAC method integrated the advantages of both methods and had the best correction effect. When continuous outliers with the same characteristics occurred in the initiation stage of quality control, the progressive EOF method might unreasonably eliminate observations. However, the progressive EOFs method could effectively solve this problem and had better performance in data quality control. The progressive EOFs quality control method with the combined BHC-BAC method could obviously reject outliers. The observation increment (deviations between observations and background field) after quality control by the progressive EOFs method was the closest to normal distribution, satisfying the Gaussian distribution assumption of data assimilation.
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Bieringer, Paul E., Peter S. Ray, and Andrew J. Annunzio. "The Effect of Topographic Variability on Initial Condition Sensitivity of Low-Level Wind Forecasts. Part II: Experiments Using Real Terrain and Observations." Monthly Weather Review 141, no. 7 (July 1, 2013): 2156–72. http://dx.doi.org/10.1175/mwr-d-11-00055.1.

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Abstract A study by Bieringer et al., which is Part I of this two-part study, demonstrated analytically using the shallow-water equations and numerically in controlled experiments that the presence of terrain can result in an enhancement of sensitivities to initial condition adjustments. The increased impact of adjustments to initial conditions corresponds with gradients in the flow field induced by the presence of the terrain obstacle. In cross-barrier flow situations the impact of the initial condition adjustments on the final forecast increases linearly as the height of the terrain obstacle increases. While this property associated with initial condition perturbations may be present in an analytic and controlled numerical environment, it is often difficult to realize these benefits in a more operationally realistic setting. This study extends the prior work to a situation with actual terrain, Doppler radar wind observations over the terrain, and observations from a surface mesonet for model verification. The results indicate that the downstream surface wind forecast was improved more when the initial conditions adjusted through the assimilation of Doppler radar data originated from areas with terrain gradients than from regions where the terrain was relatively flat. This result is consistent with the findings presented in Part I and suggests that when varying terrain elevation is present upstream of a target forecast area, a greater benefit (in terms of forecast accuracy) can be made by targeting additional observations in the regions containing variable terrain than regions where the terrain is relatively flat.
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Carr, Michael H. "Mars Global Surveyor observations of Martian fretted terrain." Journal of Geophysical Research: Planets 106, E10 (October 1, 2001): 23571–93. http://dx.doi.org/10.1029/2000je001316.

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Grant, Eleanor R., Andrew N. Ross, Barry A. Gardiner, and Stephen D. Mobbs. "Field Observations of Canopy Flows over Complex Terrain." Boundary-Layer Meteorology 156, no. 2 (March 12, 2015): 231–51. http://dx.doi.org/10.1007/s10546-015-0015-y.

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Lewis, H. W., S. D. Mobbs, and M. Lehning. "Observations of cross‐ridge flows across steep terrain." Quarterly Journal of the Royal Meteorological Society 134, no. 633 (April 2008): 801–16. http://dx.doi.org/10.1002/qj.259.

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Dissertations / Theses on the topic "Observations de terrain"

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Ward, Andrew Craig. "Modified convective models using wind, turbulence and dispersion information for an inland region with complex terrain : thesis." Thesis, Queensland University of Technology, 1991. https://eprints.qut.edu.au/35975/1/35975_Ward_1991.pdf.

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Four dispersion models have been investigated using data from a variety of sites. The models consisted of a standard Gaussian model, a Gaussian model modified for Australian conditions by the incorporation of empirical formulations for plume rise and spread, and two convective models. Comparison of the models' predictions with laboratory results suggested that the convective models generally were able to predict better the variation of concentration with distance and buoyancy. Residual analyses were used to examine model biases. A performance measure and a ranking procedure were developed in order to rank the predictive ability of the models. Improvements in the models were made by the incorporation of results from the examination of plume spread formulations, inversion interaction schemes, optimisation, and sensitivity analyses. A simple scheme was developed to assist in the choice of a model under particular meteorological and source conditions. Overall, the models which treated separately plume motion in updraughts and downdraughts were able to predict better the ground level concentration in a variety of conditions. Two simple slab models for predicting the depth of the convective boundary layer were compared with radiosonde and lidar measurements.
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Escadafal, Richard. "Caracterisation de la surface des sols arides par observations de terrain et par teledetection." Paris 6, 1989. http://www.theses.fr/1989PA066175.

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Martin, Claire. "La famille des Melastomataceae : des observations sur le terrain à l'analyse du genre Leandra Raddi." Paris, Muséum national d'histoire naturelle, 2007. http://www.theses.fr/2006MNHN0030.

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La famille des Melastomataceae comprend environ 4500-5000 espèces réparties en 150-166 genres divisés en 9 tribus. La tribu néotropicale des Miconieae comprend environ 1800-2000 espèces. La délimitation des genres qui la composent est souvent obscure et arbitraire, et rend l`identification des espèces souvent difficile, spécialement pour les genres morphologiquement proches : Leandra Raddi, Miconia Ruiz & Pavon et Ossaea DC. De nombreuses observations sur le terrain ont permis de constater l`incroyable diversité des espèces de Melastomataceae et leur aptitude à conquérir tous les milieux. Ces observations ont abouti à une analyse de la structure architecturale de certaines espèces colonisatrices de zones perturbées. Après les premiers travaux sur l'architecture, une analyse phylogénétique du genre Leandra a été entreprise. Cette étude ne pouvait se faire sans réaliser en parallèle un travail nomenclatural approfondi (réalisation de référentiels taxonomiques et lectotypifications). L'analyse phylogénétique moléculaire du genre Leandra a été réalisée sur le gène nrITS, elle inclut 224 espèces de la tribu des Miconieae dont 63 espèces de Leandra et démontre la polyphylie du genre. Les résultats de cette première analyse reliée aux caractères morphologiques des graines étudiées chez les espèces de Leandra et des trois autres genres proches cités précédemment ont permis d'émettre l'hypothèse que la morphologie des graines pouvait constituer un caractère valable afin d`aider à clarifier la problématique délimitation des genres.
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Fauconnier, Julien. "Anisotropie, fusion partielle et déformation de la croûte continentale : étude expérimentale et observations de terrain." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066560/document.

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La localisation de la déformation est une caractéristique nécessaire de la tectonique. Pour localiser la déformation, une roche doit subir un affaiblissement. Le processus affaiblissant principal des roches est l'interconnexion de phases faibles. Dans le cas de la croûte continentale, les phases faibles étant le plus souvent responsables de la localisation sont les micas et les liquides silicatés résultant de la fusion partielle. Bien qu'il existe des études expérimentales sur la rhéologie des micas, il y a très peu d'études sur l'impact des micas sur la localisation dans les conditions de la croûte continentale inférieure. De même, les précédentes études expérimentales montrent l'effet de la fusion partielle sur la résistance des roches mais elles utilisent toutes un matériel de départ isotrope. Or la croûte subissant la fusion partielle dans les orogènes est susceptible d'être préalablement déformée et donc anisotrope. Dans le but d'apporter de nouvelles données sur le comportement mécanique et les microstructures de la croûte continentale anisotrope, ainsi que sur l'effet des micas sur la localisation de la déformation, cette thèse propose de réaliser une série d’expériences en presse de Griggs. Cette approche expérimentale est aussi couplée à un travail de terrain sur la zone de faille de Møre og Trøndelag (Norvège). Cette structure étant un zone de cisaillement d'échelle crustale dont la cinématique est partiellement synchrone de la fusion partielle, elle est adaptée à l'étude naturelle des relations entre fusion partielle et déformation
Strain localization is a necessary feature of tectonic. To be able to localize deformation, rocks must undergo weakening. The main weakening process is weak phase interconnection. For continental crust, weak phases that are the most often responsible of strain localization are micas and melt. Although previous experimental studies exist about rheological properties of micas, none are about the effect of micas on the strain localization in the lower continental crust conditions. Previous experimental studies about the effect of partial melting were always done with isotropic starting material. But continental crust which undergo partial melting is very likely to be deformed before melting and therefore to be highly anisotropic. In the aim to bring new data about mechanical behavior and microstructures of anisotropic continental crust, as well as the effect of micas on strain localization, this thesis propose to conduct a series of experiments in a Griggs apparatus. This experimental approach is also coupled with field work on the Møre og Trøndelag Fault Zone (Norway). This crustal scale shear zone was partially synchronous with partial melting and therefore is well suited for studying relation ship between deformation and partial melting
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Fauconnier, Julien. "Anisotropie, fusion partielle et déformation de la croûte continentale : étude expérimentale et observations de terrain." Electronic Thesis or Diss., Paris 6, 2016. http://www.theses.fr/2016PA066560.

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La localisation de la déformation est une caractéristique nécessaire de la tectonique. Pour localiser la déformation, une roche doit subir un affaiblissement. Le processus affaiblissant principal des roches est l'interconnexion de phases faibles. Dans le cas de la croûte continentale, les phases faibles étant le plus souvent responsables de la localisation sont les micas et les liquides silicatés résultant de la fusion partielle. Bien qu'il existe des études expérimentales sur la rhéologie des micas, il y a très peu d'études sur l'impact des micas sur la localisation dans les conditions de la croûte continentale inférieure. De même, les précédentes études expérimentales montrent l'effet de la fusion partielle sur la résistance des roches mais elles utilisent toutes un matériel de départ isotrope. Or la croûte subissant la fusion partielle dans les orogènes est susceptible d'être préalablement déformée et donc anisotrope. Dans le but d'apporter de nouvelles données sur le comportement mécanique et les microstructures de la croûte continentale anisotrope, ainsi que sur l'effet des micas sur la localisation de la déformation, cette thèse propose de réaliser une série d’expériences en presse de Griggs. Cette approche expérimentale est aussi couplée à un travail de terrain sur la zone de faille de Møre og Trøndelag (Norvège). Cette structure étant un zone de cisaillement d'échelle crustale dont la cinématique est partiellement synchrone de la fusion partielle, elle est adaptée à l'étude naturelle des relations entre fusion partielle et déformation
Strain localization is a necessary feature of tectonic. To be able to localize deformation, rocks must undergo weakening. The main weakening process is weak phase interconnection. For continental crust, weak phases that are the most often responsible of strain localization are micas and melt. Although previous experimental studies exist about rheological properties of micas, none are about the effect of micas on the strain localization in the lower continental crust conditions. Previous experimental studies about the effect of partial melting were always done with isotropic starting material. But continental crust which undergo partial melting is very likely to be deformed before melting and therefore to be highly anisotropic. In the aim to bring new data about mechanical behavior and microstructures of anisotropic continental crust, as well as the effect of micas on strain localization, this thesis propose to conduct a series of experiments in a Griggs apparatus. This experimental approach is also coupled with field work on the Møre og Trøndelag Fault Zone (Norway). This crustal scale shear zone was partially synchronous with partial melting and therefore is well suited for studying relation ship between deformation and partial melting
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Richer, de Forges Anne. "Exploration du potentiel de données d'observations de terrain pour caractériser ou cartographier des propriétés ou des comportements des sols." Electronic Thesis or Diss., Orléans, 2024. http://www.theses.fr/2024ORLE1049.

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Lors de l'élaboration de cartographies des sols ou de la description des sols sur le terrain, de très nombreuses variables sont observées, collectées et enregistrées en base de données. Au fil du temps, ces données sur les sols deviennent disponibles en masse mais certaines n'ont jamais été étudiées dans leur globalité, ni valorisées pour caractériser ou cartographier des propriétés, des fonctionnements ou des comportements des sols. Ces données sont essentiellement qualitatives et souvent ordinales. L'hypothèse de notre travail est qu'il est possible de catégoriser ces variables, de les mettre en relation avec des données quantitatives et de les valoriser en cartographie des sols par modélisation statistique (ou digital soil mapping : DSM).Nous évaluons le bénéfice de l'apport de ces données incertaines en prenant deux exemples fondés sur la texture et la compacité. Nous simulons les conséquences d'utilisation de la texture de terrain sur la calibration et les performances d'une fonction de pédotransfert. Nous montrons également le potentiel important de cette donnée en DSM, tant comme donnée d'entrée, que comme donnée de validation de prédictions de fractions granulométriques. Cette masse de données, de sources parfois hétégogènes, permet également de révéler des structures spatiales non capturées par les variables quantitatives disponibles. Nous utilisons un test de terrain d'estimation de la compacité des sols pour mettre en évidence des clusters de comportement physique qui sont ensuite interprétés et cartographiés à l'échelle nationale.Par ces exemples, nous démontrons que l'utilisation en masse de données qualitatives peut apporter de nouvelles connaissances et être valorisée par l'exploration et le DSM. Nous confirmons également le potentiel de données issues de la télédétection, telle que la spectrogammamétrie aéroportée, comme covariable pour le DSM de la granulométrie des horizons de surface des sols. Nous montrons en particulier qu'il est possible d'extraire des bases de données des informations utilisables et spatialisables à partir de données qualitatives incertaines, sans nécessairement recourir à de nouvelles acquisitions plus coûteuses
When carrying soil survey or describing soils in the field, a large number of variables are observed, recorded and stored in databases. Over time, this data on soils becomes available overwhelmingly. However, this data has never been studied in its entirety, nor used to characterize or map soil properties, functioning or behavior. These data are essentially qualitative and often ordinal. The hypothesis of our work is that it is possible to categorize these variables, to relate them to quantitative data and to use them in digital soil mapping (DSM).We evaluate the benefit of the contribution of this uncertain data by taking two examples based on soil texture and compactness. We simulate the consequences of using the hand-feel texture on the calibration and performance of a pedotransfer function. We also show the significant potential of this data in DSM of particle-size fractions, both as input data and as validation data. This mass of data, sometimes from heterogeneous sources, also makes it possible to reveal spatial structures not captured by the available quantitative variables. We use a field test to estimate soil compactness to bring out clusters of physical behavior which are then interpreted and mapped on a national scale.Through these examples, we demonstrate that the mass use of qualitative data can provide new knowledge and be enhanced by exploration and the DSM. We also confirm the potential of data from remote sensing, such as airborne spectrogammametry, as a covariate for the DSM of particle-size of topsoil. In particular, we show that it is possible to extract usable and spatially relevant information from uncertain qualitative data, without necessarily resorting to new, more costly acquisitions
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Homan, Paul B. "Evaluation of high density surface observations in complex terrain and their contribution to the MM5 model." Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion.exe/07Mar%5FHoman.pdf.

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Davranche, Mélanie. "Impacts des processus aux interfaces solide/liquide sur la mobilité des éléments : Observations de terrain-Expérimentation-modélisation." Habilitation à diriger des recherches, Université Rennes 1, 2008. http://tel.archives-ouvertes.fr/tel-00289457.

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One of the key research issues in surface geochemistry is to understand the processes responsible of the surface water compositions to both improve fundamental knowledge of controlling mechanisms and protection of water resources. Processes occurring at solid-solution interface are predominant among the known involved chemical mechanisms. Solids, such as soil colloids, particles, sediments or colloids occurring as suspension in waters, present very large specific surfaces. This latter point gives them strong complexation or sequestration properties for elements such as metals, trace elements...These solids include mineral (oxyhydroxydes Fe and Mn, silicates, carbonates ...), organic colloid (humic substances...) and biological cells (algae, bacteria...) bound or not in between them. Sorption, co-precipitation and surface precipitation are the three major processes at interfaces involving these solid surfaces. They partly control the mobility and dissolved concentrations of metals and trace elements in waters and soil solutions. However, these processes are themselves controlled by physico-chemical parameters such as pH, Eh, T..., the solid nature and the interactions in between. The present work has therefore been focused on assessing the influence of these factors on the reactivity of elements at solid/solution interfaces. To address this issue, a combined approach involving laboratory experiments and modelling to answer to the questions identified in the field, was used. Firstly, the impact of redox condition variations on the mobilization of metals sourced in minerals (natural and synthetic oxyhydroxydes Fe and Mn, and slags from metallurgic industry) was experimentally evaluated. In a second step, this work was focused on the in situ monitoring of the iron cycle in a natural wetland soil. This implied the development of an innovative tool allowing the insertion of synthetic iron oxides directly in soil horizons. This research has been conducted to identify the impact of the iron oxides reductive dissolution and/or mineralogical changes on the mobilization of associated trace elements. Since organic matter release is often linked to iron reductive dissolution in wetland soil solutions, two experimental studies were also conducted: (i) on the redox condition impact on the dynamics of organic matter and trace element mobility and (ii) on the impact of organic complexation on the rare earth element (REE) speciation in solution. This work is ended by a research project dedicated to the rare earth element partitioning at solid-water interface and its impact on REE geochemical behaviour and associated fingerprinting properties.
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Lévy, Léa. "Propriétés électriques des roches volcaniques altérées : observations et interprétations basées sur des mesures en laboratoire, terrain et forage au volcan Krafla, Islande." Thesis, Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLEE002/document.

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Afin de cartographier la structure souterraine des volcans et détecter des ressources géothermiques de haute température, on utilise souvent l’imagerie de résistivité électrique. La résistivité électrique des volcans est affectée par plusieurs facteurs: volume et salinité de l’eau interstitielle, abondance de minéraux conducteurs, température de la roche et présence de magma. Ce travail de thèse tente de contraindre l'interprétation des structures de résistivité électrique autour des volcans actifs, afin de développer des outils innovants pour l'exploration des ressources géothermiques. La contribution des minéraux conducteurs est au cœur de la thèse: conducteurs ioniques solides (minéraux argileux, en particulier la smectite) ou semi-conducteurs électroniques (pyrite, oxydes de fer), mais l’influence de la porosité, de la salinité, de la température et de la présence de magma est aussi étudiée. La thèse utilise le volcan Krafla comme terrain d’étude pour affiner les interprétations des structures de résistivité électriques, du fait de la disponibilité de carottes, de données, de bibliographie et d’infrastructure. La smectite et la pyrite sont formées par altération hydrothermale des roches volcaniques et témoignent ainsi des convections hydrothermales. Les oxydes de fer en revanche sont plutôt formés lors de la cristallisation du magma et sont dissous lors des circulations hydrothermales. La contribution de la smectite à la conductivité électrique de roches volcaniques, saturées en eau à différentes salinités, est d'abord étudiée en laboratoire (à température ambiante) par spectroscopie d’impédance électrique « résistivité complexe ». Des variations non linéaires de la conductivité électrique à 1 kHz avec la salinité sont observées et discutées. La conduction interfoliaire est suggérée comme un mécanisme important par lequel la smectite conduit le courant électrique. L'influence de la pyrite et des oxydes de fer sur les effets de polarisation provoquée est ensuite analysée en utilisant l'angle de phase de l'impédance, qui dépend de la fréquence. Un angle de phase maximal supérieur à 20 mrad est attribué à la pyrite si la roche est conductrice et aux oxydes de fer si la roche est résistive. L'angle de phase maximal augmente d'environ 22 mrad pour chaque pourcent de pyrite ou d'oxyde de fer. Ces résultats de laboratoire en domaine fréquentiel sont appliqués à l’interprétation de tomographies de résistivité complexe sur le terrain en domaine temporel. Smectite, pyrite et oxydes de fer ont pu être identifiés jusqu'à 200 m de profondeur. La température in-situ, plus élevées qu’en laboratoire, semble augmenter la conductivité de la smectite. De manière générale, la tomographie de résistivité complexe est recommandée comme méthode complémentaire aux sondages électromagnétiques pour l'exploration géothermique
Electromagnetic soundings are widely used to image the underground structure of volcanoes and look for hightemperature geothermal resources. The electrical resistivity of volcanoes is affected by several characteristics of rocks: volume and salinity of pore fluid, abundance of conductive minerals, rock temperature and presence of magma. This thesis aims at improving the interpretation of electrical resistivity structures around active volcanoes, in order to develop innovative tools for the assessment of geothermal resources. I focus on conductive minerals, which can either be solid ionic conductors (clay minerals, in particular smectite) or electronic semi-conductors (pyrite and iron-oxides), but I also investigate the effects of porosity, salinity, temperature and presence of magma. I use Krafla volcano as a laboratory area, where extensive literature, borehole data, core samples, surface soundings and infrastructures are available. Smectite and pyrite are formed upon hydrothermal alteration of volcanic rocks and thus witness hydrothermal convection. On the other hand, iron-oxides are mostly formed during the primary crystallization of magma and dissolved by hydrothermal fluids. The contribution of smectite to the electrical conductivity of volcanic rocks saturated with pore water at different salinity is first investigated in the laboratory (room temperature) by electrical impedance spectroscopy “complex resistivity”. Non-linear variations of the conductivity at 1 kHz with salinity are observed and discussed. Interfoliar conduction is suggested as an important mechanism by which smectite conducts electrical current. The influence of pyrite and iron-oxides on induced polarization effects is then analyzed, using the frequency-dependent phase-angle of the impedance. A maximum phase-angle higher than 20 mrad is attributed to pyrite if the rock is conductive and to ironoxides if the rock is resistive. The maximum phase-angle increases by about 22 mrad for each additional per cent of pyrite or iron-oxide. These laboratory frequency-domain findings are partly upscaled to interpret field time-domain complex resistivity tomography at Krafla: smectite, pyrite and iron-oxides can be identified down to 200 m. The in-situ temperature, higher than in laboratory conditions, appears to significantly increase the conductivity associated to smectite. In general, time-domain complex resistivity measurements are recommended as a complementary method to electromagnetic soundings for geothermal exploration
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Schlögel, Romy. "Quantitative landslide hazard assessment with remote sensing observations and statistical modelling." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAH009/document.

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La création d’inventaires de glissements de terrain sert de base à l’évaluation quantitative de l’aléa et à la gestion du risque. Les cartes d’inventaires de mouvements gravitaires sont produites en utilisant des méthodes conventionnelles (campagnes de mesures de terrain, interprétation visuelle de photographies aériennes) et par des techniques de télédétection plus innovantes. Une des techniques les plus prometteuses pour la détection et la cartographie des glissements de terrain fait appel à la mesure de la déformation du sol par interférométrie radar satellitaire (InSAR). Cette thèse est consacrée à la constitution d’un inventaire multi-dates à partir de données multi-sources (incluant les données InSAR) en vue d’évaluer de façon quantitative l’aléa glissement de terrain. Les méthodes associent l’analyse de produits d’Observation de la Terre et des modélisations statistiques pour la caractérisation de l’aléa dans la vallée de l’Ubaye, une région rurale et montagneuse des Alpes du Sud. Elles ont été développées à l’échelle du versant (1:5.000-1:2.000) et à l’échelle régionale (1:25.000- 1:10.000). Pour la création des inventaires, cette étude propose une interprétation combinée de séries temporelles d’images SAR, de photographies aériennes, de cartes géomorphologiques, de rapports historiques et de campagnes de terrain. A l’échelle locale, une méthodologie d'interprétation guidée par la géomorphologie et utilisant l’InSAR a été proposée pour identifier les champs de déplacement des glissements de terrain et mesurer leur évolution. A l’échelle régionale, la distribution spatio-temporelle des glissements de terrain a été caractérisée et l’aléa a été calculé à partir des probabilités d’occurrence spatiale et temporelle pour une intensité donnée des phénomènes. L’occurrence spatiale est estimée grâce à un modèle multivarié (régression logistique). L’occurrence temporelle des mouvements gravitaires est évaluée grâce à un modèle de probabilité de Poisson permettant de calculer la probabilité de dépassement (incluant ou non un seuil de surface) pour plusieurs périodes de retour. Plusieurs unités d'analyse spatiale ont été utilisées pour la modélisation ; les résultats démontrent clairement leur influence sur les résultats. L’analyse de l’aléa a été réalisée sur quelques cas spécifiques. Des relations entre les (ré)activations de glissements de terrain et les facteurs déclenchants sont proposées
The analysis of landslide inventories is the basis for quantitative hazard assessment. Landslide inventory maps are prepared using conventional methods (field surveys, visual interpretation of aerial photographs) and new remote sensing techniques. One of the most promising techniques for landslide detection and mapping is related to the measurement of the ground deformation by satellite radar interferometry (InSAR).This doctoral thesis is dedicated to the preparation of a multi-date inventory, from multi-source data, including InSAR, for a quantitative assessment of landslide hazard. The methods associate the analysis of Earth Observation products and statistical modelling for the characterization of landslide hazard in a rural and mountainous region of the South French Alps. They have been developed at the slope (1:5000-1:2000) and the regional (1:25.000-1:10.000) scales. For the creation of a multi-date inventory, this study developed a combined interpretation of time series of SAR images, aerial photographs, geomorphological maps, historical reports and field surveys. At the slope-scale, a geomorphologically-guided methodology using InSAR was proposed to identify landslide displacement patterns and measure their kinematic evolution. At regional scale, spatio-temporal distribution of landslides is characterised and hazard is assessed by computing spatial and temporal probabilities of occurrence for a given intensity of the phenomena. The spatial occurrence is evaluated using a multivariate model (logistic regression). The temporal occurrence of landslide is estimated with a Poisson probability model to compute exceedance probabilities for several return periods. Different mapping units were used in the modelling, and their influence on the results is discussed. Analysis of landslide hazard is then proposed for some particular hotspots. Relationships between landslide (re)activations and triggering factors are envisaged
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Books on the topic "Observations de terrain"

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Troxel, S. W. Observations of plume dispersion in complex terrain by NOAA lidar during the 1984 Full Scale Plume Study at Tracy Power Plant. Boulder, Colo: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories, 1986.

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Melgarejo, José W. An analytical model of the boundary layer above sloping terrain with an application to observations in Antarctica. Norrköpping: SMHI, 1986.

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Sardan, Jean-Pierre Olivier de. La rigueur du qualitatif: Les contraintes empiriques de l'interprétation socio-anthropologique. Louvain-La-Neuve: Academia-Bruylant, 2008.

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Kuznar, Lawrence A. Reclaiming a scientific anthropology. Walnut Creek, CA: AltaMira Press, 1997.

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Plouff, Donald. Field estimates of gravity terrain corrections and Y2K-compatible method to convert from gravity readings with multiple base stations to tide- and long-term drift-corrected observations. Menlo Park, CA: U.S. Dept. of the Interior, U.S. Geological Survey, 2000.

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Geological Survey (U.S.), ed. Field estimates of gravity terrain corrections and Y2K-compatible method to convert from gravity readings with multiple base stations to tide- and long-term drift-corrected observations. Menlo Park, CA: U.S. Dept. of the Interior, U.S. Geological Survey, 2000.

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Geological Survey (U.S.), ed. Field estimates of gravity terrain corrections and Y2K-compatible method to convert from gravity readings with multiple base stations to tide- and long-term drift-corrected observations. Menlo Park, CA: U.S. Dept. of the Interior, U.S. Geological Survey, 2000.

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Johnson, Victoria. Collaborative research on road weather observations and predictions by universities, state DOTs and National Weather Service Forecast Offices. McLean, Va: Turner-Fairbank Highway Research Center, 2004.

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Pertti, Heinonen, Ziglio G, and Beken André van der, eds. Hydrological and limnological aspects of lake monitoring. Chichester: Wiley, 2000.

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Didier, Fassin, and Bensa Alban, eds. Les politiques de l'enquête: Épreuves ethnographiques. Paris: La Découverte, 2008.

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Book chapters on the topic "Observations de terrain"

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Whiteman, C. David. "Observations of Thermally Developed Wind Systems in Mountainous Terrain." In Atmospheric Processes over Complex Terrain, 5–42. Boston, MA: American Meteorological Society, 1990. http://dx.doi.org/10.1007/978-1-935704-25-6_2.

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Noonan, J. A., W. L. Physick, J. N. Carras, and D. J. Williams. "Dispersion Modelling and Observations from Elevated Sources in Coastal Terrain." In Air Pollution Modeling and Its Application X, 533–40. Boston, MA: Springer US, 1994. http://dx.doi.org/10.1007/978-1-4615-1817-4_56.

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Gao, Gui. "Target Detection and Terrain Classification of Single-Channel SAR Images." In Characterization of SAR Clutter and Its Applications to Land and Ocean Observations, 75–101. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-1020-1_3.

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Santabàrbara, J. M., J. F. Hernández, J. Calbó, L. Cremades, T. Mikkelsen, and J. M. Baldasano. "Wind Flow over Rolling Terrain: A Comparison of Three Recent Models and Full-Scale Observations." In Air Pollution Modeling and Its Application XI, 583–91. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4615-5841-5_60.

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Vigne, Jean‑Denis, Jean Guilaine, Antigone Marangou, Philippe Béarez, Maria Rousou, Yodrik Franel, Régis Touquet, and François Briois. "Les occupations de la culture de Sotira (5e millénaire av. n. è.) et de ­l’Antiquité et leur impact sur les dépôts ­pré-céramiques." In Klimonas, 59–66. Paris: CNRS Éditions, 2024. http://dx.doi.org/10.4000/129jx.

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Ce chapitre résume les observations de terrain et l’étude du mobilier témoignant de l’occupation des trois terrasses de Klimonas après l’abandon du village PPNA. Deux périodes sont bien documentées. Le Néolithique avec céramique de la culture Sotira est représenté par les restes d’un, voire de plusieurs bâtiments implantés sur la terrasse moyenne, accompagnés de nombreux creusements ayant parfois sérieusement endommagé les vestiges du Néolithique pré-céramique. Après une nouvelle phase d’abandon, le versant a fait l’objet d’activités agricoles (terrasses, labours, fosses de plantation) de façon plus ou moins continue entre l’Âge du Fer et la période protobyzantine. Cette troisième phase n’a toutefois entraîné que des dégâts mineurs pour les vestiges pré-céramiques, les murs de terrasse ayant parfois contribué à leur protection.
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Huntley, David, Drew Rotheram-Clarke, Kelvin Sattler, and David Elwood. "Surficial Geology and Geomorphology of the North Slide, Thompson River Valley, British Columbia, Canada: Application of Fundamental Geoscience Information to Interpretations of Geospatial Monitoring Results." In Progress in Landslide Research and Technology, 221–38. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-44296-4_10.

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AbstractOur study focuses on a slow-moving landslide in the Thompson River valley, south-central British Columbia, Canada, that has posed a hazard to the national railway transportation corridor since 1880. Real-time kinematic global navigation satellite systems, unoccupied aerial vehicles, and satellite synthetic aperture radar interferometry time-series show significant displacement encroaching on railway infrastructure. In this paper, geospatial relationships between landslide distribution and specific terrain features, and the environmental conditions triggering instability are determined from field-based geological observations. We describe how earth material stratigraphy, textures, and penetrative planar structures are important controls on sub-surface drainage, and how these factors influence the style, timing, and rate of slope displacement. West of the railway tracks, slide scarps extend across the toe slope, corresponding to narrow zones of high displacement, presence of perennial springs and seepage, and cutbank erosion along the river channel. Fluvial incision exposes weak, failure-prone units at the base of the fill sequence, and with ongoing channel migration promotes instability by altering landslide toe geometry. Currently, the zone of potential displacement does not extend upslope into the inactive (1880) main slide body, east of the tracks. Seasonal variations in hydrogeological conditions influence the spatial and temporal patterns of surface water and groundwater flow, in turn controlling the distribution of translational-rotational displacement of slide blocks, and rates of movement on reactivated shear surfaces that extend under Thompson River. Slope failure occurs along weak, sub-horizontal shear zones within poorly drained glaciolacustrine clay and silt units, overlain by rapidly drained glaciofluvial outwash gravel, and imperfectly drained till diamicton. River levels exert a complex control on landslide stability, influencing hydraulic gradients within the basal glaciolacustrine unit, particularly along rupture surfaces within it. Ground displacement occurs while river levels are at their lowest between February and March, before peak flows in June, or after July until December while storm-fed river levels progressively lower to the next winter minimum. Groundwater levels remain elevated in the slide body throughout the year, contained in porous gravel and sand beds, and along brittle fractures and sub-horizonal shear zones in silt-clay varve beds. Geospatial and temporal change-detection monitoring of active landslides and at-risk infrastructure, when benchmarked with terrain and hydrogeological observations, is a cost-effective hazard management practice that provides important geoscience information to help develop appropriate early warning, mitigation, adaptation, and risk reduction measures.
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Kloch, G., and J. Krynski. "On the Determination of the Terrain Correction Using the Spherical Approach." In Gravity, Geoid and Earth Observation, 389–95. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-10634-7_52.

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Vantsevich, V., D. Gorsich, A. Lozynskyy, L. Demkiv, T. Borovets, and S. Klos. "Agile Tyre Mobility: Observation and Control in Severe Terrain Environments." In NATO Science for Peace and Security Series B: Physics and Biophysics, 247–58. Dordrecht: Springer Netherlands, 2020. http://dx.doi.org/10.1007/978-94-024-2021-0_22.

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Steyn, Douw, Ekaterina Batchvarova, Marina Baldi, Bob Banta, Xiaoming Cai, Sven-Erik Gryning, and Ray Hoff. "Observation and Modelling of Boundary Layer Depth in a Region with Complex Terrain and Coastline." In Air Pollution Modeling and Its Application XII, 311–19. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4757-9128-0_32.

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Pramanik, Anilendu, Deepti Majumdar, Tirthankar Chatterjee, Bodhisattwa Chowdhury, and Dhurjati Majumdar. "Dynamic Analysis of Load Carriage on Physiology and Biomechanics During Simulated Terrain Walking: A Continuous Observational Approach." In Design Science and Innovation, 171–84. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-6982-8_16.

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Conference papers on the topic "Observations de terrain"

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Zhang, Hongru, and Li Fan. "Exploring in Uneven Terrain: A Novel Map Representation and Decision-Making with Frontier Observations." In 2024 International Conference on Advanced Robotics and Mechatronics (ICARM), 1069–74. IEEE, 2024. http://dx.doi.org/10.1109/icarm62033.2024.10715859.

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Rajak, Akanksha M., and Deepak Subramani. "Comparison of Convolutional Autoencoder Architectures for Representation Learning of MODIS Aqua and Terra Observations." In IGARSS 2024 - 2024 IEEE International Geoscience and Remote Sensing Symposium, 7576–79. IEEE, 2024. http://dx.doi.org/10.1109/igarss53475.2024.10640481.

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Chen, Qingqing, Fang Miao, Zi-Xin Xu, Hao Wang, Ling Yang, and Zhiya Tang. "Downscaling of Remote Sensing Soil Moisture Products Based on TVDI in Complex Terrain Areas." In 2019 International Conference on Meteorology Observations (ICMO). IEEE, 2019. http://dx.doi.org/10.1109/icmo49322.2019.9026012.

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Romick, G., D. Morrison, Robert Sears, R. O'Neil, R. Hegblom, and E. Richards. "Multispectral observations of atmospheric, terrain, and cloud clutter from MSX." In 36th AIAA Aerospace Sciences Meeting and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1998. http://dx.doi.org/10.2514/6.1998-289.

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Emmitt, G. D., and K. Godwin. "Advanced airborne Doppler Wind Lidar signal processing for observations in complex terrain." In SPIE Remote Sensing, edited by Upendra N. Singh and Gelsomina Pappalardo. SPIE, 2014. http://dx.doi.org/10.1117/12.2068226.

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Wyszkowska, Patrycja, and Robert Duchnowski. "Assessing vertical terrain displacement from TLS data by applying Msplit estimation – theoretical analysis." In 5th Joint International Symposium on Deformation Monitoring. Valencia: Editorial de la Universitat Politècnica de València, 2022. http://dx.doi.org/10.4995/jisdm2022.2022.13677.

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Terrestrial laser scanning (TLS) is a measurement technique that has become popular in the last decades. Measurement results, usually as a point cloud, contain many points measured. When the TLS technique is used to determine terrain surface (e.g., by determining terrain profiles), one should realize that some points measured do not concern the terrain surface itself, but trees, shrubs, or generally the vegetation cover. Considering terrain surface determination, they should be regarded as outliers. Some other observations can also be outliers of different origins; for example, they might be disturbed by gross errors. We should consider such observation types when the data are processed. Two leading solutions in such a context are data cleaning and the application of robust estimation methods. Robust M-estimation is the most popular for the latter approach. As an alternative, one can also consider the application of Msplit estimation, in which the functional model is split into two competing ones. Hence, the paper aims to analyze how Msplit estimation can assess vertical terrain displacement based on terrain profile determination from TLS data. We consider processing data in separate sets (two measurement epochs) or one combined set, a natural approach in Msplit estimation. The analyses based on simulated TLS data proved that the first solution seems better. Furthermore, the application of Msplit estimation can also provide more satisfactory results than the classical methods used in such a context.
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Koracin, Darko, Nash'at Ahmad, Vlad Isakov, John Hallett, Mary Cairns, Sherri De, and Steven Cohn. "Predictability of local wind shear and turbulence and comparison with observations in complex terrain." In 34th Aerospace Sciences Meeting and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1996. http://dx.doi.org/10.2514/6.1996-509.

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McMichael, Joseph G., Yonggyu Gim, Darmindra D. Arumugam, and Jeffrey J. Plaut. "Radar autofocus algorithm incorporating terrain knowledge for correction of Mars' ionospheric distortion in MARSIS observations." In 2017 IEEE Radar Conference (RadarConf17). IEEE, 2017. http://dx.doi.org/10.1109/radar.2017.7944326.

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Burgess, Margo M., Scott Wilkie, Rick Doblanko, and Ibrahim Konuk. "Field Observations of Cyclical Pipe-Soil Interactions in Permafrost Terrain, KP 5, Norman Wells Pipeline, Canada." In 2000 3rd International Pipeline Conference. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/ipc2000-119.

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The Norman Wells pipeline is an 869 km long, small diameter, buried, ambient temperature, oil pipeline operated by Enbridge Pipeline (NW) Inc. in the discontinuous permafrost zone of northwestern Canada. Since operation began in 1985, average oil temperatures entering the line have been maintained slightly below 0°C, initially through constant chilling year round and since 1993 through a seasonal cycling of temperatures through a range from −4 to +9°C. At one location, 5 km from the inlet at Norman Wells, on level terrain in an area of widespread permafrost, uplift of a 20 m segment of line was observed in the early 1990s. The uplift gradually increased and by 1997 the pipe was exposed 0.5 m above the ground surface. Detailed studies at the site have included field investigations of terrain and thermal conditions, repeated pipe and ground surface elevation surveys, and annual Geopig surveys. The field work has revealed that the section of line was buried in low density soils, thawed to depths of 4 m on-right-of-way, and not subjected to complete refreezing in winter. The thaw depths are related to surface or near-surface flows from a nearby natural spring, as well as to the development of a thaw bulb around the pipe in the cleared right-of-way. Icings indicative of perennial water flow occur commonly at this location in the winter. The pipe experienced annual cycles of heave and settlement (on the order of 0.5 m) due to seasonal freezing and thawing within the surrounding low density soils. The pipe reached its highest elevation at the end of each winter freezing season, and its lowest elevation at the end of the summer thaw period. Superimposed on this heave/settlement cycle was an additional step-like cycle of increasing pipe strain related to thermal expansion and contraction of the pipe. A remedial program was initiated in the winter of 1997–98 in order to curtail the cumulative uplift of the pipe, reduce the increasing maximum annual pipe strain and ensure pipe safety. A 0.5 m cover of sandbags and coarse rock was placed over the exposed pipe segment. Continued pipe elevation monitoring and annual Geopig surveys have indicated that both seasonal heave/settlement and strains have been reduced subsequent to the remedial loading. Introduction of a gravel berm has also altered both the surrounding hydrologic and ground thermal regimes.
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Waddington, Betsy, Luc Toussaint, Rami Ghazali, and Alex Baumgard. "Performance of Terrain Mapping Estimation of Depth to Bedrock in Pipeline Construction Planning: A Case Study." In 2024 15th International Pipeline Conference. American Society of Mechanical Engineers, 2024. https://doi.org/10.1115/ipc2024-133769.

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Abstract Terrain mapping is the delineation of polygons with unique surficial geology, landforms and processes, and is often conducted at the start of a project to provide preliminary ground information, particularly in areas that have not been subject to significant development. Depth to bedrock, one of the attributes typically assigned to terrain mapping polygons, can be a key input in estimating rock excavation volumes through the design phase of a project. In this case study, design-level depth to bedrock estimation for three short new pipeline alignments routed through southeastern British Columbia are compared to detailed ground condition observations collected through construction. Possible causes of discrepancies are then discussed, leading to a review of the approach to conducting design-phase estimates for future projects.
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Reports on the topic "Observations de terrain"

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Bégin, C., S. G. Evans, M. Parent, D. Demers, G. Grondin, D. E. Lawrence, J M Aylsworth, Y. Michaud, G R Brooks, and R. Couture. Le glissement de terrain d'avril 1996 à Saint-Boniface-de-Shawinigan, Québec : observations et données préliminaires. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1996. http://dx.doi.org/10.4095/207890.

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Eylander, John, Michael Lewis, Maria Stevens, John Green, and Joshua Fairley. An investigation of the feasibility of assimilating COSMOS soil moisture into GeoWATCH. Engineer Research and Development Center (U.S.), September 2021. http://dx.doi.org/10.21079/11681/41966.

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This project objective evaluated the potential of improving linked weather-and-mobility model predictions by blending soil moisture observations from a Cosmic-ray Soil Moisture Observing System (COSMOS) sensor with weather-informed predictions of soil moisture and soil strength from the Geospatial Weather-Affected Terrain Conditions and Hazards (GeoWATCH). Assimilating vehicle-borne COSMOS observations that measure local effects model predictions of soil moisture offered potential to produce more accurate soil strength and vehicle mobility forecast was the hypothesis. This project compared soil moisture observations from a COSMOS mobile sensor driven around an area near Iowa Falls, IA, with both GeoWATCH soil moisture predictions and in situ probe observations. The evaluation of the COSMOS rover data finds that the soil moisture measurements contain a low measurement bias while the GeoWATCH estimates more closely matched the in situ data. The COSMOS rover captured a larger dynamic range of soil moisture conditions as compared to GeoWATCH, capturing both very wet and very dry soil conditions, which may better flag areas of high risk for mobility considerations. Overall, more study of the COSMOS rover is needed to better understand sensor performance in a variety of soil conditions to determine the feasibility of assimilating the COSMOS rover estimates into GeoWATCH.
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Alexander and Kiefner. L51554 Field Observations on the Two-Phase Hovenweep CO2 Gathering System During Summer Operation. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), January 1988. http://dx.doi.org/10.55274/r0010290.

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While laboratory-scale studies of single-phase flow have resulted in good correlations for the design of large-diameter pipeline systems, similar approaches for two-phase flow have not been as useful. Although theoretical modeling and simulation of single-phase turbulent flow has not yet been accomplished, empirical observation of many small-scale examples has lead to effective correlations through dimensional analysis. These correlations for a single-phase often do scale-up adequately for design of pipelines. However, when an additional phase is present, this approach has not worked well. It is likely that a better understanding of the fundamental interaction of two-turbulent phases will be necessary if small-scale studies are to be used for the design of large, high-pressure pipeline systems. A more immediate way of gaining some knowledge of two-phase flow in large diameter pipes of the complexity present in the field is to over-design a pipeline system and construct it, field tune it to specifications, then observe its behavior. This is obviously a risky and expensive approach. However, many such systems have been constructed. It is on these successful two-phase pipeline systems that our attention should be focused in the immediate future if we are to improve two-phase pipeline design now of new but similar systems. Such is the focus of this study of the Hovenweep CO2 Gathering System. The Hovenweep CO2 Gathering System was selected for study as a pipeline system that could add to the knowledge of the nature of steady-state two-phase flow in large diameter high pressure pipeline systems with hilly terrain. Characterization includes measurement of the following variables: 1. gas and liquid flow rates; 2. typical gas and liquid compositions; 3. liquid volume fractions; 4. pressure drop across each test segment; 5. temperature.
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Sharpe, D. R., G. Leduc, C. S. Smart, and J. Shaw. Georgian Bay bedrock erosion: evidence for regional floods, Ontario. Natural Resources Canada/CMSS/Information Management, 2023. http://dx.doi.org/10.4095/331409.

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We provide an updated presentation of the spectacular erosion forms at French River Ontario (Kor et al. 1991) based on new methods of data collection and wider observations. This work includes ~ 10 more detailed study sites, documentation of the range of forms over a larger area, the use of extensive drone image capture and ground surveys, as well as a detailed inventory of forms. Key sites are illustrated using video images. The update extends the conclusions of the Kor paper regarding the significance and scale of subglacial meltwater erosion with some novel findings. We document the importance of plucking (including hydraulic plucking) and, the control of structure on s-forms, which were not highlighted in the Kor study. Apparent cavitation erosion forms are prominent across the study area and provide support for inferred high-velocity meltwater flow. A growing interpretative framework includes discussion of evidence to test a theorized hydraulic sequence of sheet-channel-distributed flow, followed by re-grounding of glacial ice as meltwater flow waned. This hydraulic sequence may also be complementary to observations in thick sediment terrain down flow.
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Pugin, A. J. M., G. R. Brooks, and K. D. Brewer. Origin of mass movements and faulted glaciolacustrine deposits in the upper Lake Timiskaming area, Ontario- Quebec, using high-resolution seismic reflection. Natural Resources Canada/CMSS/Information Management, 2024. http://dx.doi.org/10.4095/p0f205dx57.

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Trois levés sismiques à haute résolution ont été réalisés sur le cours supérieur du lac Témiscamingue en 2019, 2021 et 2022 à l'aide d'une technologie de pénétration développée à la Commission géologique du Canada. Le but de ces levés était d'étudier l'origine des sédiments glaciolacustres faillés précédemment signalés. De telles structures de déformation peuvent être liées à un effondrement dû à la fonte lente de la glace enfouie, à des mouvements de masse gravitationnelle ou à un mouvement de failles profondes du substrat rocheux. De nouvelles observations révèlent une vallée profonde, allongée et érodée (tunnel) de 1,3 à 2,5 km de large et 28 km de long et située le long du bord escarpé ouest du lac. Le thalweg de cette vallée s'étend jusqu'à -150 m d'altitude et est rempli de jusqu'à ~240 m de sédiments. Plus de sédiments sont présents dans la partie supérieure du lac par rapport à la partie inférieure ; le point de division étant défini par une moraine qui forme un rétrécissement peu profond. Les marges du lac présentent quatre niveaux de terrasse qui sont cartographiés dans la zone de la baie Paulson du lac. Une grille étroite de levés de lignes sismiques révèle des réseaux de glissements de terrain enfouis et inactifs qui sont le produit de mouvements gravitationnels rampants de sédiments glaciolacustres en association avec des failles d'extension. Les levés révèlent également des trous de kettle (fonte des glaces), des cavités rocheuses et du diamicton à la base d'une séquence sédimentaire glaciolacustre. D'éventuelles structures d'affouillement et de remplissage d'icebergs sont également identifiées dans les dépôts glaciolacustres. Toutes les failles et mouvements de masse liés à la gravité observés lors des levés peuvent être expliqués par des processus glacio-tectoniques ou de mouvements de masse. Certains glissements de terrain pourraient avoir été déclenchés par des séismes induits par le rebond isostatique de la croûte terrestre lié à la fonte de l'inlandsis laurentien. Il n’existe aucun exemple de failles rocheuses profondes atteignant la surface proche et se prolongeant dans les sédiments glaciolacustres ou lacustres récents dans l’ensemble de données sismiques.
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Venäläinen, Ari, Sanna Luhtala, Mikko Laapas, Otto Hyvärinen, Hilppa Gregow, Mikko Strahlendorff, Mikko Peltoniemi, et al. Sää- ja ilmastotiedot sekä uudet palvelut auttavat metsäbiotaloutta sopeutumaan ilmastonmuutokseen. Finnish Meteorological Institute, January 2021. http://dx.doi.org/10.35614/isbn.9789523361317.

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Climate change will increase weather induced risks to forests, and thus effective adaptation measures are needed. In Säätyö project funded by the Ministry of Agriculture and Forestry, we have summarized the data that facilitate adaptation measures, developed weather and climate services that benefit forestry, and mapped what kind of new weather and climate services are needed in forestry. In addition, we have recorded key further development needs to promote adaptation. The Säätyö project developed a service product describing the harvesting conditions of trees based on the soil moisture assessment. The output includes an analysis of the current situation and a 10-day forecast. In the project we also tested the usefulness of long forecasts beyond three months. The weather forecasting service is sidelined and supplemented by another co-operation project between the Finnish Meteorological Institute and Metsäteho called HarvesterSeasons (https://harvesterseasons.com/). The HarvesterSeasons service utilizes long-term forecasts of up to 6 months to assess terrain bearing conditions. A test version of a wind damage risk tool was developed in cooperation with the Department of Forest Sciences of the University of Eastern Finland and the Finnish Meteorological Institute. It can be used to calculate the wind speeds required in a forest area for wind damage (falling trees). It is currently only suitable for researcher use. In the Säätyö project the possibility of locating the most severe wind damage areas immediately after a storm was also tested. The method is based on the spatial interpolation of wind observations. The method was used to analyze storms that caused forest damages in the summer and fall of 2020. The produced maps were considered illustrative and useful to those responsible for compiling the situational picture. The accumulation of snow on tree branches, can be modeled using weather data such as rainfall, temperature, air humidity, and wind speed. In the Säätyö project, the snow damage risk assessment model was further developed in such a way that, in addition to the accumulated snow load amount, the characteristics of the stand and the variations in terrain height were also taken into account. According to the verification performed, the importance of abiotic factors increased under extreme snow load conditions (winter 2017-2018). In ordinary winters, the importance of biotic factors was emphasized. According to the comparison, the actual snow damage could be explained well with the tested model. In the interviews and workshop, the uses of information products, their benefits, the conditions for their introduction and development opportunities were mapped. According to the results, diverse uses and benefits of information products and services were seen. Information products would make it possible to develop proactive forest management, which would reduce the economic costs caused by wind and snow damages. A more up-to-date understanding of harvesting conditions, enabled by information products, would enhance the implementation of harvesting and harvesting operations and the management of timber stocks, as well as reduce terrain, trunk and root damage. According to the study, the introduction of information is particularly affected by the availability of timeliness. Although the interviewees were not currently willing to pay for the information products developed in the project, the interviews highlighted several suggestions for the development of information products, which could make it possible to commercialize them.
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Mbaye, Safiétou, Rémi Kouabenan, and Philippe Sarnin. L'explication naïve et la perception des risques comme des voies pour améliorer les pratiques de REX: des études dans l'industrie chimique et l'industrie nucléaire. Fondation pour une culture de sécurité industrielle, September 2009. http://dx.doi.org/10.57071/311rex.

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L’analyse de l’accident soulève de nombreux enjeux dont le poids préfigure également des biais possibles dans l’explication causale et laisse apparaître que l’explication de l’accident peut difficilement être neutre. En l’occurrence, les difficultés rencontrées dans la conduite du REX relèvent en grande partie de conflits qui surviennent lors des analyses d’accidents. Ce document présente quatre études de terrain qui visaient à comprendre l’origine des conflits entre les acteurs du REX lors des analyses d’accidents et à mieux appréhender le rôle de la perception des risques et du climat de sécurité dans la motivation des acteurs à s’impliquer davantage dans les pratiques de REX. Les études sont conduites dans l’industrie chimique et l’industrie nucléaire et portent sur plus de 1000 agents de tous niveaux hiérarchiques (cadres, agents de maîtrise, techniciens, ouvriers) et tous domaines d’activité (prévention, production, maintenance, qualité). La méthodologie repose sur des entretiens, des observations de comité REX, une expérimentation et l’administration de deux questionnaires. Il en ressort que les démarches de REX sont davantage subies qu’elles ne sont portées par les responsables du traitement des accidents en raison des coûts qu’elles engendrent en temps et en énergie, mais aussi à cause du manque d’opérationnalité des règles de traitement des accidents. Il s’avère ensuite que l’absence de dialogue autour des causes des accidents entretient des doutes sur la crédibilité du REX auprès des opérateurs. Mais avant tout, il est clairement établi que la peur d’endosser la responsabilité de l’accident détermine fortement l’explication de l’accident qui devient notamment très défensive. Par exemple, les cadres et les ouvriers se renvoient systématiquement la causalité des accidents: plus ils se sentent menacés par l’analyse d’accident, plus ils en attribuent la survenue à des facteurs internes à l’autre groupe hiérarchique. Les études révèlent également comment les croyances sur les risques conduisent les individus à être plus attentifs au REX sur les accidents directement liés au cœur de métier de leur industrie et moins attentifs au REX sur les accidents de la vie courante, pourtant plus nombreux et plus graves. Enfin, nous montrons en quoi un bon climat de sécurité peut favoriser l’implication des acteurs dans les pratiques de REX.
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Percival, J. A., and J. B. Whalen. Observations on the North Caribou terrane-Uchi Subprovince interface in western Ontario and eastern Manitoba. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2000. http://dx.doi.org/10.4095/211160.

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Renaud, Alexander, Michael Forte, Nicholas Spore, Brittany Bruder, Katherine Brodie, Jessamin Straub, and Jeffrey Ruby. Evaluation of Unmanned Aircraft Systems for flood risk management : results of terrain and structure assessments. Engineer Research and Development Center (U.S.), August 2022. http://dx.doi.org/10.21079/11681/45000.

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The 2017 Duck Unmanned Aircraft Systems (UAS) Pilot Experiment was conducted by the US Army Engineer Research and Development Center (ERDC), Coastal and Hydraulics Laboratory, Field Research Facility (FRF), to assess the potential for different UAS to support US Army Corps of Engineers coastal and flood risk management. By involving participants from multiple ERDC laboratories, federal agencies, academia, and private industry, the work unit leads were able to leverage assets, resources, and expertise to assess data from multiple UAS. This report compares datasets from several UAS to assess their potential to survey and observe coastal terrain and structures. In this report, UAS data product accuracy was analyzed within the context of three potential applications: (1) general coastal terrain survey accuracy across the FRF property; (2) small-scale feature detection and observation within the experiment infrastructure area; and (3) accuracy for surveying coastal foredunes. The report concludes by presenting tradeoffs between UAS accuracy and the cost to operate to aid in selection of the best UAS for a particular task. While the technology and exact UAS models vary through time, the lessons learned from this study illustrate that UAS are available at a variety of costs to satisfy varying coastal management data needs.
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Davidson, A., and J. W. F. Ketchum. Observations on the Maberly Shear Zone, a terrane boundary within the central metasedimentary belt, Grenville Province, Ontario. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1993. http://dx.doi.org/10.4095/134253.

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