Pour voir les autres types de publications sur ce sujet consultez le lien suivant : Deep Earth dynamics.
Articles de revues sur le sujet « Deep Earth dynamics »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleurs articles de revues pour votre recherche sur le sujet « Deep Earth dynamics ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les articles de revues sur diverses disciplines et organisez correctement votre bibliographie.
1
Ihnatyshyn, V., D. Malytskyi et Y. Koval'. « Oash deep fault zone : earth`s crust dynamics ». Visnyk of Taras Shevchenko National University of Kyiv. Geology, no 65 (2014) : 36–39. http://dx.doi.org/10.17721/1728-2713.65.07.
Texte intégral
2
Lay, Thorne, Quentin Williams et Edward J. Garnero. « The core–mantle boundary layer and deep Earth dynamics ». Nature 392, no 6675 (avril 1998) : 461–68. http://dx.doi.org/10.1038/33083.
Texte intégral
3
Heine, Christian, R. Dietmar Müller, Bernhard Steinberger et Lydia DiCaprio. « Integrating deep Earth dynamics in paleogeographic reconstructions of Australia ». Tectonophysics 483, no 1-2 (mars 2010) : 135–50. http://dx.doi.org/10.1016/j.tecto.2009.08.028.
Texte intégral
4
Saito, Tatsuhiko, et Tatsuya Kubota. « Tsunami Modeling for the Deep Sea and Inside Focal Areas ». Annual Review of Earth and Planetary Sciences 48, no 1 (30 mai 2020) : 121–45. http://dx.doi.org/10.1146/annurev-earth-071719-054845.
Texte intégralRésumé :
This article reviews tsunami modeling and its relation to recent developments of deep-ocean observations. Unlike near-coast observations, deep-ocean observations have enabled the capture of short-wavelength dispersive tsunamis and reflected waves from the coast. By analyzing these waves, researchers can estimate tsunami sources and earthquake slip distributions more reliably with higher spatial resolution. In addition, fractional tsunami speed reduction due to the elasticity of the Earth medium is now clearly detected. Densely and widely distributed tsunami sensors make it possible to observe tsunamis inside the earthquake focal area, and understanding tsunami generation mechanisms is increasingly important. In order to describe the generation field, we should consider seismic waves overlapping tsunami signals in addition to vertical and horizontal displacements at the sea bottom. The importance of elastic dynamics, in addition to fluid dynamics, is increasing in order for researchers to fully understand tsunami phenomena using the new offshore and inside focal area observations. ▪ Deep-ocean observations have advanced tsunami propagation modeling. ▪ New deep-ocean observations in earthquake focal areas are expected to detect in situ tsunami generation caused by megathrust earthquakes. ▪ The importance of elastic dynamics, in addition to fluid dynamics, is increasing to help researchers fully understand mechanics in tsunami generation and propagation. ▪ Tsunami modeling including earthquake rupture and seismic waves contributes to mega-thrust earthquake investigation and disaster mitigation.
5
Zhan, Zhongwen. « Mechanisms and Implications of Deep Earthquakes ». Annual Review of Earth and Planetary Sciences 48, no 1 (30 mai 2020) : 147–74. http://dx.doi.org/10.1146/annurev-earth-053018-060314.
Texte intégralRésumé :
Deep earthquakes behave like shallow earthquakes but must have fundamentally different physical processes. Their rupture behaviors, magnitude-frequency statistics, and aftershocks are diverse and imperfectly dependent on various factors, such as slab temperature, depth, and magnitude. The three leading mechanisms for deep earthquakes (i.e., transformational faulting, dehydration embrittlement, and thermal runaway) can each explain portions of the observations but have potentially fundamental difficulties explaining the rest. This situation calls for more serious consideration of hypotheses that involve more than one mechanism. For example, deep earthquakes may initiate by one mechanism, but the ruptures may propagate via another mechanism once triggered. To make further progress, it is critical to evaluate the hypotheses, both single- or dual-mechanism, under conditions as close to those of real slabs as possible to make accurate and specific predictions that are testable using seismic or other geophysical observations. Any new understanding of deep earthquakes promises new constraints on subduction zone structure and dynamics. ▪ Deep earthquakes display the complex structure and dynamics of subduction zones in terms of geometry, stress state, rheology, hydration, and phase changes. ▪ Phase transformation, dehydration, and thermal runaway are the leading mechanisms for deep earthquakes, but all have major gaps or fundamental difficulties. ▪ Deep earthquakes may involve dual-mechanism processes, as hinted at by the diverse rupture and statistic properties and the break of self-similarity. ▪ Further progresses would benefit from specific and testable predictions that consider realistic slab conditions with insights from geodynamics, petrology, and mineral physics.
6
Zhatnuev, N. S. « The dynamics of deep magmas ». Doklady Earth Sciences 430, no 2 (février 2010) : 176–80. http://dx.doi.org/10.1134/s1028334x10020066.
Texte intégral
7
Anghelea, Anca, Ewelina Dobrowolska, Gunnar Brandt, Martin Reinhardt, Miguel Mahecha, Tejas Morbagal Harish et Stephan Meissl. « Deep Earth System Data Laboratory (DeepESDL) ». International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVIII-4-2024 (21 octobre 2024) : 13–18. http://dx.doi.org/10.5194/isprs-archives-xlviii-4-2024-13-2024.
Texte intégralRésumé :
Abstract. The Deep Earth System Data Lab (DeepESDL) provides an AI-ready, collaborative environment for researchers aiming to study the Earth's complex dynamics using various datasets and empirical approaches. Recently opened to Early Adopters, it builds on projects like CAB-LAB and ESDL, utilizing well-established Python and Julia technology stacks. DeepESDL offers programmatic access to extensive analysis-ready data cubes and computational resources, enabling researchers to focus on analysis without extensive preparations. Scientists can use persistently available data cubes or generate user-tailored cubes from own data or publicly available datasets. The goal is to streamline data processing through empirical or AI methods within high-dimensional Earth Observation workflows. DeepESDL addresses the complete research cycle, from discovery of earth data to powerful analyses, collaborative scientific research, advanced data visualisation and publication of results, promoting FAIR and Open Science. Apart from serving as a research environment, DeepESDL showcases scientific use cases and supports educational purposes through capacity building, academic programs, and Open Science initiatives. This paper presents an overview of DeepESDL.
8
Ferreira, Antónia, João Rolim, Paula Paredes et Maria do Rosário Cameira. « Assessing Spatio-Temporal Dynamics of Deep Percolation Using Crop Evapotranspiration Derived from Earth Observations through Google Earth Engine ». Water 14, no 15 (27 juillet 2022) : 2324. http://dx.doi.org/10.3390/w14152324.
Texte intégralRésumé :
Excess irrigation may result in deep percolation and nitrate transport to groundwater. Furthermore, under Mediterranean climate conditions, heavy winter rains often result in high deep percolation, requiring the separate identification of the two sources of deep percolated water. An integrated methodology was developed to estimate the spatio-temporal dynamics of deep percolation, with the actual crop evapotranspiration (ETc act) being derived from satellite images data and processed on the Google Earth Engine (GEE) platform. GEE allowed to extract time series of vegetation indices derived from Sentinel-2 enabling to define the actual crop coefficient (Kc act) curves based on the observed lengths of crop growth stages. The crop growth stage lengths were then used to feed the soil water balance model ISAREG, and the standard Kc values were derived from the literature; thus, allowing the estimation of irrigation water requirements and deep drainage for independent Homogeneous Units of Analysis (HUA) at the Irrigation Scheme. The HUA are defined according to crop, soil type, and irrigation system. The ISAREG model was previously validated for diverse crops at plot level showing a good accuracy using soil water measurements and farmers’ irrigation calendars. Results show that during the crop season, irrigation caused 11 ± 3% of the total deep percolation. When the hotspots associated with the irrigation events corresponded to soils with low suitability for irrigation, the cultivated crop had no influence. However, maize and spring vegetables stood out when the hotspots corresponded to soils with high suitability for irrigation. On average, during the off-season period, deep percolation averaged 54 ± 6% of the annual precipitation. The spatial aggregation into the Irrigation Scheme scale provided a method for earth-observation-based accounting of the irrigation water requirements, with interest for the water user’s association manager, and at the same time for the detection of water losses by deep percolation and of hotspots within the irrigation scheme.
9
Syrris, Vasileios, et Sveinung Loekken. « Editorial of Special Issue “Machine and Deep Learning for Earth Observation Data Analysis” ». Remote Sensing 13, no 14 (14 juillet 2021) : 2758. http://dx.doi.org/10.3390/rs13142758.
Texte intégral
10
Nakagawa, Takashi, et Tomoeki Nakakuki. « Dynamics in the Uppermost Lower Mantle : Insights into the Deep Mantle Water Cycle Based on the Numerical Modeling of Subducted Slabs and Global-Scale Mantle Dynamics ». Annual Review of Earth and Planetary Sciences 47, no 1 (30 mai 2019) : 41–66. http://dx.doi.org/10.1146/annurev-earth-053018-060305.
Texte intégralRésumé :
In this review, we address the current status of numerical modeling of the mantle transition zone and uppermost lower mantle, focusing on the hydration mechanism in these areas. The main points are as follows: ( a) Slab stagnation and penetration may play significant roles in transporting the water in the whole mantle, and ( b) a huge amount of water could be absorbed into the deep mantle to preserve the surface seawater over the geologic timescale. However, for further understanding of water circulation in the deep planetary interior, more mineral physics investigations are required to reveal the mechanism of water absorption in the lower mantle and thermochemical interaction across the core–mantle boundary region, which can provide information on material properties to the geodynamics community. Moreover, future investigations should focus on determining the amount of water in the early planetary interior, as suggested by the planetary formation theory of rocky planets. Moreover, the supplying mechanism of water during planetary formation and its evolution caused by plate tectonics are still essential issues because, in geodynamics modeling, a huge amount of water seems to be required to preserve the surface seawater in the present day and to not be dependent on an initial amount of water in Earth's system. ▪ Slab stagnation and penetration of the hydrous lithosphere are essential for understanding the global-scale material circulation. ▪ Thermal feedback caused by water-dependent viscosity is a main driving mechanism of water absorption in the mantle transition zone and uppermost lower mantle. ▪ The hydrous state in the early rocky planets remains to be determined from cosmo- and geochemistry and planetary formation theory. ▪ Volatile cycles in the deep planetary interior may affect the evolution of the surface environment.
11
Akhverdiev, A. T. « ORIGIN OF GLOBAL DEEP FAULTS AND THEIR SIGNIFICANCE IN EARTH DEGASIFICATION ». Мінеральні ресурси України, no 4 (28 décembre 2018) : 32–36. http://dx.doi.org/10.31996/mru.2018.4.32-36.
Texte intégralRésumé :
There are origin and formation conditions of global deep faults, their distribution patterns and also their importance in the Earth degasification from standpoint of conception of Earth Crust evolution dynamics (CECED) in article. According to this conception geodynamic forces form during Earth rotation and all geological processes includig transition of lithospheric masses and their destruction, are followed by: formation of global deep faults; intracrustal anomalous processes represented by plumes, sutures, diapers, etc; volcanic-plutonic processes and earth quakes; by formation of fold mountain systems, etc.
12
Sanloup, Chrystele. « High-pressure experimental geosciences : state of the art and prospects ». Bulletin de la Société Géologique de France 183, no 3 (1 mai 2012) : 175–87. http://dx.doi.org/10.2113/gssgfbull.183.3.175.
Texte intégralRésumé :
Abstract This paper aims at reviewing the current advancements of high pressure experimental geosciences. The angle chosen is that of in situ measurements at the high pressure (P) and high temperature (T) conditions relevant of the deep Earth and planets, measurements that are often carried out at large facilities (X-ray synchrotrons and neutron sources). Rather than giving an exhaustive catalogue, four main active areas of research are chosen: the latest advancements on deep Earth mineralogy, how to probe the properties of melts, how to probe Earth dynamics, and chemical reactivity induced by increased P-T conditions. For each area, techniques are briefly presented and selected examples illustrate their potentials, and what that tell us about the structure and dynamics of the planet.
13
Keller, Klaus, Casey Helgeson et Vivek Srikrishnan. « Climate Risk Management ». Annual Review of Earth and Planetary Sciences 49, no 1 (30 mai 2021) : 95–116. http://dx.doi.org/10.1146/annurev-earth-080320-055847.
Texte intégralRésumé :
Accelerating global climate change drives new climate risks. People around the world are researching, designing, and implementing strategies to manage these risks. Identifying and implementing sound climate risk management strategies poses nontrivial challenges including ( a) linking the required disciplines, ( b) identifying relevant values and objectives, ( c) identifying and quantifying important uncertainties, ( d) resolving interactions between decision levers and the system dynamics, ( e) quantifying the trade-offs between diverse values under deep and dynamic uncertainties, ( f) communicating to inform decisions, and ( g) learning from the decision-making needs to inform research design. Here we review these challenges and avenues to overcome them. ▪ People and institutions are confronted with emerging and dynamic climate risks. ▪ Stakeholder values are central to defining the decision problem. ▪ Mission-oriented basic research helps to improve the design of climate risk management strategies.
14
Tackley, Paul J., Michael M. Ammann, John P. Brodholt, David P. Dobson et Diana Valencia. « Habitable Planets : Interior Dynamics and Long-Term Evolution ». Proceedings of the International Astronomical Union 8, S293 (août 2012) : 339–49. http://dx.doi.org/10.1017/s1743921313013136.
Texte intégralRésumé :
AbstractHere, the state of our knowledge regarding the interior dynamics and evolution of habitable terrestrial planets including Earth and super-Earths is reviewed, and illustrated using state-of-the-art numerical models. Convection of the rocky mantle is the key process that drives the evolution of the interior: it causes plate tectonics, controls heat loss from the metallic core (which generates the magnetic field) and drives long-term volatile cycling between the atmosphere/ocean and interior. Geoscientists have been studying the dynamics and evolution of Earth's interior since the discovery of plate tectonics in the late 1960s and on many topics our understanding is very good, yet many first-order questions remain. It is commonly thought that plate tectonics is necessary for planetary habitability because of its role in long-term volatile cycles that regulate the surface environment. Plate tectonics is the surface manifestation of convection in the 2900-km deep rocky mantle, yet exactly how plate tectonics arises is still quite uncertain; other terrestrial planets like Venus and Mars instead have a stagnant lithosphere- essentially a single plate covering the entire planet. Nevertheless, simple scalings as well as more complex models indicate that plate tectonics should be easier on larger planets (super-Earths), other things being equal. The dynamics of terrestrial planets, both their surface tectonics and deep mantle dynamics, change over billions of years as a planet cools. Partial melting is a key process influencing solid planet evolution. Due to the very high pressure inside super-Earths' mantles the viscosity would normally be expected to be very high, as is also indicated by our density function theory (DFT) calculations. Feedback between internal heating, temperature and viscosity leads to a superadiabatic temperature profile and self-regulation of the mantle viscosity such that sluggish convection still occurs.
15
Auclair-Desrotour, P., S. Mathis, J. Laskar et J. Leconte. « Oceanic tides from Earth-like to ocean planets ». Astronomy & ; Astrophysics 615 (juillet 2018) : A23. http://dx.doi.org/10.1051/0004-6361/201732249.
Texte intégralRésumé :
Context. Oceanic tides are a major source of tidal dissipation. They drive the evolution of planetary systems and the rotational dynamics of planets. However, two-dimensional (2D) models commonly used for the Earth cannot be applied to extrasolar telluric planets hosting potentially deep oceans because they ignore the three-dimensional (3D) effects related to the ocean’s vertical structure. Aims. Our goal is to investigate, in a consistant way, the importance of the contribution of internal gravity waves in the oceanic tidal response and to propose a modelling that allows one to treat a wide range of cases from shallow to deep oceans. Methods. A 3D ab initio model is developed to study the dynamics of a global planetary ocean. This model takes into account compressibility, stratification, and sphericity terms, which are usually ignored in 2D approaches. An analytic solution is computed and used to study the dependence of the tidal response on the tidal frequency and on the ocean depth and stratification. Results. In the 2D asymptotic limit, we recover the frequency-resonant behaviour due to surface inertial-gravity waves identified by early studies. As the ocean depth and Brunt–Väisälä frequency increase, the contribution of internal gravity waves grows in importance and the tidal response becomes 3D. In the case of deep oceans, the stable stratification induces resonances that can increase the tidal dissipation rate by several orders of magnitude. It is thus able to significantly affect the evolution time scale of the planetary rotation.
16
Mandea, Mioara, Véronique Dehant et Anny Cazenave. « GRACE—Gravity Data for Understanding the Deep Earth’s Interior ». Remote Sensing 12, no 24 (21 décembre 2020) : 4186. http://dx.doi.org/10.3390/rs12244186.
Texte intégralRésumé :
While the main causes of the temporal gravity variations observed by the Gravity Recovery and Climate Experiment (GRACE) space mission result from water mass redistributions occurring at the surface of the Earth in response to climatic and anthropogenic forces (e.g., changes in land hydrology, ocean mass, and mass of glaciers and ice sheets), solid Earth’s mass redistributions were also recorded by these observations. This is the case, in particular, for the glacial isostatic adjustment (GIA) or the viscous response of the mantle to the last deglaciation. However, it has only recently been shown that the gravity data also contain the signature of flows inside the outer core and their effects on the core–mantle boundary (CMB). Detecting deep Earth’s processes in GRACE observations offers an exciting opportunity to provide additional insight into the dynamics of the core–mantle interface. Here, we present one aspect of the GRACEFUL (GRavimetry, mAgnetism and CorE Flow) project, i.e., the possibility to use gravity field data for understanding the dynamic processes inside the fluid core and core–mantle boundary of the Earth, beside that offered by the geomagnetic field variations.
17
Frolova, Margarita A., Nikita S. Tsvetov, Roman G. Kushlyaev et Svetlana V. Drogobuzhskaya. « Study of the process of dissolution of lanthanum hydroxide in deep eutectic solvents ». Transactions of the Kоla Science Centre of RAS. Series : Engineering Sciences 13, no 1/2022 (27 décembre 2022) : 260–64. http://dx.doi.org/10.37614/2949-1215.2022.13.1.045.
Texte intégralRésumé :
Deep eutectic solvents are potentially promising media for metals from various materials, including rocks. Of particular interest is the possibility of extracting rare earth elements, the demand for which is growing due to the expansion of their consumption. However, there are little data on the solubility of rare earth element compounds in deep eutectic. The purpose of this work is to study the process of dissolution of compounds of rare earth elements, in particular lanthanum hydroxide, in deep eutectic solvents. The dynamics of the dissolution of lanthanum hydroxide in deep eutectic solvents based on choline chloride and malonic, malic, tartaric and citric acids, was investigated. It was found that the concentration of lanthanum when using a deep eutectic solvent with tartaric acid almost immediately reaches a plateau, with malonic and malic acid it gradually decreases, and with citric acid it increases. The highest concentration of lanthanum is achieved by using a mixture of choline chloride with citric acid — 10.9 g / l.
18
Scipioni, Roberto, Lars Stixrude et Michael P. Desjarlais. « Electrical conductivity of SiO2 at extreme conditions and planetary dynamos ». Proceedings of the National Academy of Sciences 114, no 34 (7 août 2017) : 9009–13. http://dx.doi.org/10.1073/pnas.1704762114.
Texte intégralRésumé :
Ab intio molecular dynamics simulations show that the electrical conductivity of liquid SiO2 is semimetallic at the conditions of the deep molten mantle of early Earth and super-Earths, raising the possibility of silicate dynamos in these bodies. Whereas the electrical conductivity increases uniformly with increasing temperature, it depends nonmonotonically on compression. At very high pressure, the electrical conductivity decreases on compression, opposite to the behavior of many materials. We show that this behavior is caused by a novel compression mechanism: the development of broken charge ordering, and its influence on the electronic band gap.
19
Liu, Lei, Longxing Yang, Chunqiang Zhuang, Guangshu Yang, Li Yi, Hong Liu, Fengxia Sun, Xiaoyu Gu et Hanyu Wang. « Diffusion of CO2 in Magnesite under High Pressure and High Temperature from Molecular Dynamics Simulations ». Geofluids 2021 (16 juin 2021) : 1–9. http://dx.doi.org/10.1155/2021/6621425.
Texte intégralRésumé :
CO2 transports in the Earth’s interior play a crucial role in understanding the deep carbon cycle and the global climate changes. Currently, CO2 transports inside of the Earth under extreme condition of pressure and temperature have not been understood well. In this study, the molecular dynamics (MD) calculations were performed to study CO2 transports under different CO2 pressures in slit-like magnesite pores with different pore sizes at 350~2500 K and 3~50 GPa are presented. Diffusion of CO2 in magnesite was improved as the temperature increases but showed the different features as a function of pressure. The diffusion coefficients of CO2 in magnesite were found in the range of 9 × 10 − 12 m 2 s − 1 ~ 28000 × 10 − 12 m 2 s − 1 . Magnesite with the pore size of 20~25 Å corresponds to the highest transports. Anisotropic diffusion of CO2 in magnesite may help to understand the inhomogeneous distribution of carbon in the upper mantle. The time of CO2 diffusion from the mantle to Earth surface was estimated to be around several tens of Ma and has an important effect on deep carbon cycle. The simulation of CO2 transports based on the Earth condition provides new insights to revealing the deep carbon cycle in the Earth’s interiors.
20
van der Voort, Tessa Sophia, Utsav Mannu, Frank Hagedorn, Cameron McIntyre, Lorenz Walthert, Patrick Schleppi, Negar Haghipour et Timothy Ian Eglinton. « Dynamics of deep soil carbon – insights from <sup>14</sup>C time series across a climatic gradient ». Biogeosciences 16, no 16 (29 août 2019) : 3233–46. http://dx.doi.org/10.5194/bg-16-3233-2019.
Texte intégralRésumé :
Abstract. Quantitative constraints on soil organic matter (SOM) dynamics are essential for comprehensive understanding of the terrestrial carbon cycle. Deep soil carbon is of particular interest as it represents large stocks and its turnover times remain highly uncertain. In this study, SOM dynamics in both the top and deep soil across a climatic (average temperature ∼ 1–9 ∘C) gradient are determined using time-series (∼20 years) 14C data from bulk soil and water-extractable organic carbon (WEOC). Analytical measurements reveal enrichment of bomb-derived radiocarbon in the deep soil layers on the bulk level during the last 2 decades. The WEOC pool is strongly enriched in bomb-derived carbon, indicating that it is a dynamic pool. Turnover time estimates of both the bulk and WEOC pool show that the latter cycles up to a magnitude faster than the former. The presence of bomb-derived carbon in the deep soil, as well as the rapidly turning WEOC pool across the climatic gradient, implies that there likely is a dynamic component of carbon in the deep soil. Precipitation and bedrock type appear to exert a stronger influence on soil C turnover time and stocks as compared to temperature.
21
Novella, Davide, Sylvie Demouchy et Nathalie Bolfan-Casanova. « Deep Hydrogen Reservoirs and Longevity ». Elements 20, no 4 (1 août 2024) : 235–40. http://dx.doi.org/10.2138/gselements.20.4.235.
Texte intégralRésumé :
The oceans are voluminous H2O reservoirs that regulate climate and life on Earth. Yet much larger H2O reservoirs, potentially accounting for several oceans, may exist in the Earth’s mantle and core in the form of H atoms trapped into the structure of nominally anhydrous minerals (NAMs) and metallic alloys. Determining the size of these ‘hidden oceans’ is key to understanding planetary evolution and surface dynamics and can be done by combining data from rare natural samples with experimental and theoretical models. The longevity of these deep H reservoirs is controlled by H transport rates over geological times, which are dominated by percolation rates, once H partitions into melts, or by plate mobility, if H remains locked in NAMs.
22
Wang, Hao, et Tarek A. Elgohary. « A Simple and Accurate Apollo-Trained Neural Network Controller for Mars Atmospheric Entry ». International Journal of Aerospace Engineering 2020 (9 septembre 2020) : 1–15. http://dx.doi.org/10.1155/2020/3793740.
Texte intégralRésumé :
We present a new method to design the controller for Mars capsule atmospheric entry using deep neural networks and flight-proven Apollo entry data. The controller is trained to modulate the bank angle with data from the Apollo entry simulations. The neural network controller reproduces the classical Apollo results over a variation of entry state initial conditions. Compared to the Apollo controller as a baseline, the present approach achieves the same level of accuracy for both linear and nonlinear entry dynamics. The Apollo-trained controller is then applied to Mars entry missions. As in Earth environment, the controller achieves the desired level of accuracy for Mars missions using both linear and nonlinear entry dynamics with higher uncertainties in the entry states and the atmospheric density. The deep neural network is only trained with data from Apollo reentry simulation in an Earth model and works in both Earth and Mars environments. It achieves the desired landing accuracy for a Mars capsule. This method works with both linear and nonlinear integration and can generate the bank angle commands in real-time without a prestored trajectory.
23
Zerkle, Aubrey L. « Biogeodynamics : bridging the gap between surface and deep Earth processes ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 376, no 2132 (octobre 2018) : 20170401. http://dx.doi.org/10.1098/rsta.2017.0401.
Texte intégralRésumé :
Life is sustained by a critical and not insubstantial set of elements, nearly all of which are contained within large rock reservoirs and cycled between Earth's surface and the mantle via subduction zone plate tectonics. Over geologic time scales, plate tectonics plays a critical role in recycling subducted bioactive elements lost to the mantle back to the ocean–biosphere system, via outgassing and volcanism. Biology additionally relies on tectonic processes to supply rock-bound ‘nutrients’ to marine and terrestrial ecosystems via uplift and erosion. Thus, the development of modern-style plate tectonics and the generation of stable continents were key events in the evolution of the biosphere on Earth, and similar tectonic processes could be crucial for the development of habitability on exoplanets. Despite this vital ‘biogeodynamic’ connection, directly testing hypotheses about feedbacks between the deep Earth and the biosphere remains challenging. Here, I discuss potential avenues to bridge the biosphere–geosphere gap, focusing specifically on the global cycling and bioavailability of major nutrients (nitrogen and phosphorus) over geologic time scales. This article is part of a discussion meeting issue ‘Earth dynamics and the development of plate tectonics’.
24
McAllister, Meredith L. « A Study Of Undergraduate Students Alternative Conceptions Of Earths Interior Using Drawing Tasks ». Journal of Astronomy & ; Earth Sciences Education (JAESE) 1, no 1 (19 janvier 2015) : 23. http://dx.doi.org/10.19030/jaese.v1i1.9104.
Texte intégralRésumé :
Learning fundamental geoscience topics such as plate tectonics, earthquakes, and volcanoes requires students to develop a deep understanding of the conceptual models geologists use when describing the structure and dynamics of Earths interior. Despite the importance of these mental models underlying much of the undergraduate geoscience curriculum, surprisingly little research related to this complex idea exists in the discipline-based science education research literature. To better understand non-science-majoring undergraduates' conceptual models of Earths interior, student-generated drawings and interviews were used to probe student understanding of the Earth. Ninety-two semi-structured interviews were conducted with non-science-major college students at the beginning of an entry-level geology course at a large Midwestern university. Students were asked to draw a picture of Earths interior and provide think-aloud explanations of their drawings. The results reveal that students hold a wide range of alternative conceptions about Earth, with only a small fraction having scientifically accurate ideas. Students understandings ranged from conceptualizing Earths interior as consisting of horizontal layers of rock and dirt, to more sophisticated views with Earths interior being composed of concentric layers with unique physical and chemical characteristics. Processes occurring within Earth, such as "convection," were rarely mentioned or explained. These results provide a first-steps basis from which to further explore college students thinking and contribute to the growing body of knowledge on earth science teaching and geoscience education research.
25
Hoeser, Thorsten, Felix Bachofer et Claudia Kuenzer. « Object Detection and Image Segmentation with Deep Learning on Earth Observation Data : A Review—Part II : Applications ». Remote Sensing 12, no 18 (18 septembre 2020) : 3053. http://dx.doi.org/10.3390/rs12183053.
Texte intégralRésumé :
In Earth observation (EO), large-scale land-surface dynamics are traditionally analyzed by investigating aggregated classes. The increase in data with a very high spatial resolution enables investigations on a fine-grained feature level which can help us to better understand the dynamics of land surfaces by taking object dynamics into account. To extract fine-grained features and objects, the most popular deep-learning model for image analysis is commonly used: the convolutional neural network (CNN). In this review, we provide a comprehensive overview of the impact of deep learning on EO applications by reviewing 429 studies on image segmentation and object detection with CNNs. We extensively examine the spatial distribution of study sites, employed sensors, used datasets and CNN architectures, and give a thorough overview of applications in EO which used CNNs. Our main finding is that CNNs are in an advanced transition phase from computer vision to EO. Upon this, we argue that in the near future, investigations which analyze object dynamics with CNNs will have a significant impact on EO research. With a focus on EO applications in this Part II, we complete the methodological review provided in Part I.
26
Muslimov, Renat Kh, et Irina N. Plotnikova. « Replenishment of oil deposits from the position of a new concept of oil and gas formation ». Georesursy 21, no 4 (30 octobre 2019) : 40–48. http://dx.doi.org/10.18599/grs.2019.4.40-48.
Texte intégralRésumé :
The article is devoted to the problem of replenishing of oil reserves and considers it (the problem) in the aspect of deep degassing of the Earth. Based on an analysis of the results of a long-term study of the Precambrian crystalline basement in the territory of Tatarstan and adjacent areas, a number of new criteria are formulated that allow us to identify the processes of deep degassing of the Earth within the studied region. The article provides a brief overview of current views on the problem of replenishing oil reserves, considers options for possible sources and the mechanism of replenishment of hydrocarbons in the developed deposits. The arguments in favor of the modern process of deep degassing within the South Tatar arch and adjacent territories are examined, which are unequivocally confirmed by: the dynamics of the hydrochemical parameters of the deep waters of the crystalline basement obtained in the monitoring mode at five deep wells; uneven heat flux and its anomalies, recorded according to many years of research under the guidance of N.N. Khristoforova. The degassing processes are also confirmed by the dynamics of gas saturation of decompressed zones of the crystalline basement recorded in well 20009-Novoelkhovskaya, the dynamics of gas saturation of oil of the sedimentary cover and the composition of the gas dissolved in it, identified by oil studies in piezometric wells located in different areas of the Romashkinskoye field; the seismicity of the territory of Tatarstan, as well as its neotectonic activity. As criteria proving the existence of a process of replenishing the reserves of the developed oil fields of the South Tatar Arch, the features of the deep structure of the earth’s crust according to seismic data, as well as the results of geochemical studies of oils are considered.
27
Zhao, Dapeng. « Global tomographic images of mantle plumes and subducting slabs : insight into deep Earth dynamics ». Physics of the Earth and Planetary Interiors 146, no 1-2 (août 2004) : 3–34. http://dx.doi.org/10.1016/j.pepi.2003.07.032.
Texte intégral
28
Gain, Sarah E. M., William L. Griffin et Suzanne Y. O'Reilly. « Deep-earth methane and mantle dynamics : insights from northern Israel, southern Tibet and Kamchatka »,. Journal and proceedings of the Royal Society of New South Wales 149, no 1-2 (décembre 2016) : 17–33. http://dx.doi.org/10.5962/p.361751.
Texte intégral
29
Hallmann, Christian, Lorenz Schwark et Kliti Grice. « Community dynamics of anaerobic bacteria in deep petroleum reservoirs ». Nature Geoscience 1, no 9 (10 août 2008) : 588–91. http://dx.doi.org/10.1038/ngeo260.
Texte intégral
30
Arveson, Sarah M., Jie Deng, Bijaya B. Karki et Kanani K. M. Lee. « Evidence for Fe-Si-O liquid immiscibility at deep Earth pressures ». Proceedings of the National Academy of Sciences 116, no 21 (8 mai 2019) : 10238–43. http://dx.doi.org/10.1073/pnas.1821712116.
Texte intégralRésumé :
Seismic observations suggest that the uppermost region of Earth’s liquid outer core is buoyant, with slower velocities than the bulk outer core. One possible mechanism for the formation of a stably stratified layer is immiscibility in molten iron alloy systems, which has yet to be demonstrated at core pressures. We find immiscibility between liquid Fe-Si and Fe-Si-O persisting to at least 140 GPa through a combination of laser-heated diamond-anvil cell experiments and first-principles molecular dynamics simulations. High-pressure immiscibility in the Fe-Si-O system may explain a stratified layer atop the outer core, complicate differentiation and evolution of the deep Earth, and affect the structure and intensity of Earth’s magnetic field. Our results support silicon and oxygen as coexisting light elements in the core and suggest that SiO2 does not crystallize out of molten Fe-Si-O at the core-mantle boundary.
31
Richard, A., S. Galle, M. Descloitres, J. M. Cohard, J. P. Vandervaere, L. Séguis et C. Peugeot. « Riparian forest and permanent groundwater : a key coupling for balancing the hillslope water budget in Sudanian West Africa ». Hydrology and Earth System Sciences Discussions 10, no 5 (2 mai 2013) : 5643–86. http://dx.doi.org/10.5194/hessd-10-5643-2013.
Texte intégralRésumé :
Abstract. Forests are thought to play an important role in the regional dynamics of the West African monsoon, through their capacity to extract water from permanent aquifers located deep in the soil and pump it into the atmosphere even during the dry season. This is especially true for riparian forests located at the bottom of the hillslopes. This coupling between the riparian forests and the permanent aquifers is investigated, looking for quantifying its contribution to the catchment water balance. To this end, use is made of the observations available from a comprehensively instrumented hillslope through the framework of the AMMA-CATCH (African Monsoon Multidisciplinary Analysis – Coupling the Tropical Atmosphere and the Hydrological Cycle) observing system. Attention is paid to measurements of actual evapotranspiration, soil moisture and deep groundwater level. A vertical 2-D approach is followed using the physically-based Hydrus 2-D model in order to simulate the hillslope hydrodynamics, the model being calibrated and evaluated through a multi-criteria approach. The model correctly simulates the hydrodynamics of the hillslope as far as soil moisture dynamics, deep groundwater fluctuation and actual evapotranspiration dynamics are concerned. In particular, the model is able to reproduce the observed hydraulic disconnection between the deep permanent groundwater table and the river. A virtual experiment shows that the riparian forest depletes the deep groundwater table level through transpiration occurring throughout the year so that the permanent aquifer and the river are not connected. Moreover the riparian forest and the deep groundwater table form a coupled transpiration system: the riparian forest transpiration is due to the water redistribution at the hillslope scale feeding the deep groundwater through lateral saturated flow. The annual cycle of the transpiration origin is also quantified. The riparian forest which covers only 5% of the hillslope generates 37% of the annual transpiration, this proportion reaching 57% during the dry season. In a region of intense anthropogenic pressure, forest clearing and its replacement by cropping could impact significantly the water balance at catchment scale with a possible feedback on the regional monsoon dynamics.
32
Horita, Juske, et Veniamin B. Polyakov. « Carbon-bearing iron phases and the carbon isotope composition of the deep Earth ». Proceedings of the National Academy of Sciences 112, no 1 (15 décembre 2014) : 31–36. http://dx.doi.org/10.1073/pnas.1401782112.
Texte intégralRésumé :
The carbon budget and dynamics of the Earth’s interior, including the core, are currently very poorly understood. Diamond-bearing, mantle-derived rocks show a very well defined peak at δ13C ≈ −5 ± 3‰ with a very broad distribution to lower values (∼−40‰). The processes that have produced the wide δ13C distributions to the observed low δ13C values in the deep Earth have been extensively debated, but few viable models have been proposed. Here, we present a model for understanding carbon isotope distributions within the deep Earth, involving Fe−C phases (Fe carbides and C dissolved in Fe−Ni metal). Our theoretical calculations show that Fe and Si carbides can be significantly depleted in 13C relative to other C-bearing materials even at mantle temperatures. Thus, the redox freezing and melting cycles of lithosphere via subduction upwelling in the deep Earth that involve the Fe−C phases can readily produce diamond with the observed low δ13C values. The sharp contrast in the δ13C distributions of peridotitic and eclogitic diamonds may reflect differences in their carbon cycles, controlled by the evolution of geodynamical processes around 2.5–3 Ga. Our model also predicts that the core contains C with low δ13C values and that an average δ13C value of the bulk Earth could be much lower than ∼−5‰, consistent with those of chondrites and other planetary body. The heterogeneous and depleted δ13C values of the deep Earth have implications, not only for its accretion−differentiation history but also for carbon isotope biosignatures for early life on the Earth.
33
Hou, Songyan, Thomas Krabichler et Marcus Wunsch. « Deep Partial Hedging ». Journal of Risk and Financial Management 15, no 5 (19 mai 2022) : 223. http://dx.doi.org/10.3390/jrfm15050223.
Texte intégralRésumé :
Using techniques from deep learning, we show that neural networks can be trained successfully to replicate the modified payoff functions that were first derived in the context of partial hedging by Föllmer and Leukert. Not only does this approach better accommodate the realistic setting of hedging in discrete time, it also allows for the inclusion of transaction costs as well as general market dynamics. It needs to be noted that, without further modifications, the approach works only if the risk aversion is beyond a certain level.
34
Joye, Samantha B. « The Geology and Biogeochemistry of Hydrocarbon Seeps ». Annual Review of Earth and Planetary Sciences 48, no 1 (30 mai 2020) : 205–31. http://dx.doi.org/10.1146/annurev-earth-063016-020052.
Texte intégralRésumé :
Hydrocarbon seeps, deep sea extreme environments where deeply sourced fluids discharge at the seabed, occur along continental margins across the globe. Energy-rich reduced substrates, namely hydrocarbons, support accelerated biogeochemical dynamics, creating unique geobiological habitats. Subseafloor geology dictates the surficial expression of seeps, generating hydrocarbon (gas and/or oil) seeps, brine seeps, and mud volcanoes. Biogeochemical processes across the redox spectrum are amplified at hydrocarbon seeps due to the abundance and diversity of reductant; anaerobic metabolism dominates within the sediment column since oxygen is consumed rapidly near the sediment surface. Microbial activity is constrained by electron acceptor availability, with rapid recycling required to support observed rates of hydrocarbon consumption. Geobiologic structures, from gas hydrate to solid asphalt to authigenic minerals, form as a result of hydrocarbon and associated fluid discharge. Animal-microbial associations and symbioses thrive at hydrocarbon seeps, generating diverse and dense deep sea oases that provide nutrition to mobile predators. ▪ Hydrocarbon seeps are abundant deep sea oases that support immense biodiversity and where specialization and adaptation create extraordinary lifestyles. ▪ Subseafloor geology shapes and defines the geochemical nature of fluid seepage and regulates the flux regime, which dictate the surface expression. ▪ High rates of anaerobic oxidation of methane require coupling to multiple processes and promote diversity in the anaerobic methanotroph microbial community. ▪ The recent discovery of novel phyla possessing hydrocarbon oxidation potential signals that aspects of seep biogeochemistry and geobiology remain to be discovered.
35
Gaina, Carmen, Conall Mac Niocaill, Clinton P. Conrad, Bernhard Steinberger et Henrik H. Svensen. « Linking plate tectonics and volcanism to deep earth dynamics – A tribute to Trond H. Torsvik ». Tectonophysics 760 (juin 2019) : 1–3. http://dx.doi.org/10.1016/j.tecto.2019.03.002.
Texte intégral
36
Emerson, Steven, Kathy Fischer, Clare Reimers et David Heggie. « Organic carbon dynamics and preservation in deep-sea sediments ». Deep Sea Research Part A. Oceanographic Research Papers 32, no 1 (janvier 1985) : 1–21. http://dx.doi.org/10.1016/0198-0149(85)90014-7.
Texte intégral
37
Kountoura, K., et I. Zacharias. « Annual hypoxia dynamics in an enclosed gulf ». Biogeosciences Discussions 9, no 4 (25 avril 2012) : 5049–71. http://dx.doi.org/10.5194/bgd-9-5049-2012.
Texte intégralRésumé :
Abstract. Hypoxia in coastal environments is a worldwide problem and is expected to worsen in future. Due to the stratification of the water column in many enclosed or semi-enclosed gulfs, deep waters are isolated and hypoxic or anoxic conditions frequently become dominant. The most common method for the oxygenation of these isolated anoxic water masses is vertical mixing. However, there are enclosed gulfs which rarely have the appropriate energy to ensure the mixing of the entire water column. The main purpose of this paper is to find if there are any other hydrodynamic processes which can cause oxygenation of deep waters, apart from vertical mixing. In order to achieve this aim, an enclosed gulf, Amvrakikos in Western Greece, was chosen to be the case study area and bimonthly physicochemical data were collected for one year and used in combination with a three-dimensional model in order to simulate the hydrodynamic circulation of the system. According to our results, another hydrodynamic process can lead to the oxygenation of the deepest water in an enclosed gulf. This process is the horizontal intrusion of well oxygenated water from the open sea. The key factor in determining the success of this horizontal intrusion is the density difference between the deepest area of the enclosed gulf and the open sea outside the gulf. From autumn to winter, when the open sea water is denser than that inside the gulf, the well oxygenated open sea water inflows into the gulf near the bottom sea floor and re-oxygenates the isolated deep waters through mixing. However, from spring to summer, when the deep water of the gulf is characterized by higher density in comparison with the open sea water, the inflow of well oxygenated water stops, causing the development of hypoxic/anoxic conditions during the summer months.
38
Kang, Botao, Pengcheng Liu, Chenxi Li, Yiyi Sun, Peng Xiao et Jiawei Tang. « A Prediction Method for Flow-Stop Time in Deep-Water Volatile Oilfields : A Case Study of Akpo Oilfield in Niger Delta Basin ». Geofluids 2021 (14 juillet 2021) : 1–14. http://dx.doi.org/10.1155/2021/2941565.
Texte intégralRésumé :
Due to the difference in oil and water density, the wellhead pressure continues to decrease with water-cut rising in deep-water volatile oilfields. Once it is close to the lower limit, the production well will stop flowing. This phenomenon seriously affects the production and recoverable reserves. By taking the dynamic relative permeability which can reflect the macroscopic movement of oil and water in the reservoir as an intermediate bridge, production performance has been combined with dominant reservoir factors, including reservoir structure, reservoir connectivity, and heterogeneity. By the statistical analysis of actual data, this paper clarified the quantitative relationships between dominant reservoir factors and production performance and established the refined prediction methods for production dynamics including water-cut and liquid production rate. A prediction method for the wellhead pressure was further established, and the flow-stop time of single well can be accurately predicted. The results can be used in annual production forecast and recoverable reserve evaluation. This method had been successfully applied in Akpo oilfields in the Niger Basin. The results show that the production dynamics are significantly affected by reservoir factors in deep-water turbidite sandstone reservoir and the prediction method considering reservoir factors will be much more applicable. In deep-water volatile oilfields, the flow-stop risk of the production well in middle and high water-cut stages is very great and is mainly affected by the water-cut and liquid production rate. Judging from the application effect of Akpo oilfields, this method has high prediction accuracy and can be used to guide optimization and adjustment in deep-water oilfields.
39
Heron, Philip J. « Mantle plumes and mantle dynamics in the Wilson cycle ». Geological Society, London, Special Publications 470, no 1 (2019) : 87–103. http://dx.doi.org/10.1144/sp470-2018-97.
Texte intégralRésumé :
AbstractThis review discusses the thermal evolution of the mantle following large-scale tectonic activities such as continental collision and continental rifting. About 300 myr ago, continental material amalgamated through the large-scale subduction of oceanic seafloor, marking the termination of one or more oceanic basins (e.g. Wilson cycles) and the formation of the supercontinent Pangaea. The present day location of the continents is due to the rifting apart of Pangaea, with the dispersal of the supercontinent being characterized by increased volcanic activity linked to the generation of deep mantle plumes. The discussion presented here investigates theories regarding the thermal evolution of the mantle (e.g. mantle temperatures and sub-continental plumes) following the formation of a supercontinent. Rifting, orogenesis and mass eruptions from large igneous provinces change the landscape of the lithosphere, whereas processes related to the initiation and termination of oceanic subduction have a profound impact on deep mantle reservoirs and thermal upwelling through the modification of mantle flow. Upwelling and downwelling in mantle convection are dynamically linked and can influence processes from the crust to the core, placing the Wilson cycle and the evolution of oceans at the forefront of our dynamic Earth.
40
Ribeiro, Tiago, et Nir Orion. « Educating for a Holistic View of the Earth System : A Review ». Geosciences 11, no 12 (24 novembre 2021) : 485. http://dx.doi.org/10.3390/geosciences11120485.
Texte intégralRésumé :
The global society of today struggles with grand challenges, such as climate change, the degradation of ecosystems, and the loss of bio- and geodiversity, as identified in several documents. The search for solutions to these and other problems on the way to sustainable development necessarily involves a better understanding of the Earth system and its dynamics. The Earth system is composed of five highly dependent and interrelated subsystems that exchange matter and energy. This notion is at the base of what in the literature is named Earth System Science (ESS). Humanity has been profoundly altering the dynamics of this system, leading to the proposal of a new geological epoch—the Anthropocene. Developing a holistic understanding of the complex and tangled relationships between subsystems and the role of human impacts is the target of study of Earth System Education (ESE). With the assumptions of ESS, ESE is emerging as a new approach in science education. Based on a deep knowledge of the planet and the development of specific competencies, such as system thinking, it is possible to perform more actively and consciously in the relationships that citizens develop with the Earth system, enabling the existence of a more viable future for humanity.
41
Ichaoui, Mohamed, Frank Schiefer et Georg-Peter Ostermeyer. « A Novel Mesoscopic Drill Bit Model for Deep Drilling Applications ». Modelling 4, no 2 (20 juin 2023) : 296–322. http://dx.doi.org/10.3390/modelling4020017.
Texte intégralRésumé :
This paper deals with the development of a novel mesoscopic model of polycrystalline diamond compact (PDC) drill bits that can be implemented in complex drill string models for simulations to analyse the influence of rock inhomogeneities or the impact of anti-whirl bits on drill string dynamics. In contrast to existing modelling approaches, the model is developed at a mesoscopic level, where the basic bit–rock interaction is taken from the macroscopic bit model and the cutting characteristics are summarised at a microscopic cutting level into a simplified configuration via cutting blades. This model can therefore effectively describe asymmetries and thus interactions between the torsional and lateral dynamics of the drill bit, and is particularly suitable for investigating the effects of drilling into rock inhomogeneities and fault zones on drilling dynamics. By integration into a complex drill string model, simulation studies of drilling through a sandwich formation were carried out. The simulation results allow detailed stability statements and show the influence of formation properties and bit design on torsional and lateral drill string dynamics.
42
Ashkenazy, Yosef, Hezi Gildor, Martin Losch et Eli Tziperman. « Ocean Circulation under Globally Glaciated Snowball Earth Conditions : Steady-State Solutions ». Journal of Physical Oceanography 44, no 1 (1 janvier 2014) : 24–43. http://dx.doi.org/10.1175/jpo-d-13-086.1.
Texte intégralRésumé :
Abstract Between ~750 and 635 million years ago, during the Neoproterozoic era, the earth experienced at least two significant, possibly global, glaciations, termed “Snowball Earth.” While many studies have focused on the dynamics and the role of the atmosphere and ice flow over the ocean in these events, only a few have investigated the related associated ocean circulation, and no study has examined the ocean circulation under a thick (~1 km deep) sea ice cover, driven by geothermal heat flux. Here, a thick sea ice–flow model coupled to an ocean general circulation model is used to study the ocean circulation under Snowball Earth conditions. The ocean circulation is first investigated under a simplified zonal symmetry assumption, and (i) strong equatorial zonal jets and (ii) a strong meridional overturning cell are found, limited to an area very close to the equator. The authors derive an analytic approximation for the latitude–depth ocean dynamics and find that the extent of the meridional overturning circulation cell only depends on the horizontal eddy viscosity and β (the change of the Coriolis parameter with latitude). The analytic approximation closely reproduces the numerical results. Three-dimensional ocean simulations, with reconstructed Neoproterozoic continental configuration, confirm the zonally symmetric dynamics and show additional boundary currents and strong upwelling and downwelling near the continents.
43
Vočadlo, Lidunka, Atul Patel et Geoffrey D. Price. « Molecular dynamics : some recent developments in classical and quantum mechanical simulation of minerals ». Mineralogical Magazine 59, no 397 (décembre 1995) : 597–605. http://dx.doi.org/10.1180/minmag.1995.059.397.03.
Texte intégralRésumé :
AbstractWe review some of the most recent developments in classical and quantum mechanical molecular dynamics simulations, in particular as applied to Earth-forming phases at conditions prevalent in the Earth's deep interior. We pay special attention to the modelling of high pressures and temperatures, elucidating the problems associated with both the classical and quantum approaches in view of the empirical potentials required for the former, and the limitations of finite temperature calculations for the latter. We show the current status of such calculations for major phases such as MgSiO3 perovskite.
44
Kurtzman, D., L. Netzer, N. Weisbrod, A. Nasser, E. R. Graber et D. Ronen. « Characterization of deep aquifer dynamics using principle component analysis of sequential multilevel data ». Hydrology and Earth System Sciences Discussions 8, no 5 (25 octobre 2011) : 9481–503. http://dx.doi.org/10.5194/hessd-8-9481-2011.
Texte intégralRésumé :
Abstract. Two sequential multilevel profiles were obtained in an observation well opened to a 130 m thick, unconfined, contaminated aquifer, in Tel Aviv, Israel. While the general profile characteristics of major ions, trace elements, and Volatile Organic Compounds (VOC) were maintained in the two sampling campaigns conducted 295 days apart, the vertical locations of high concentration gradients were shifted between the two profiles. Principle Component Analysis (PCA) of the chemical variables resulted in a first Principal Component (PC) which was responsible for ∼60% of the variability, and was highly correlated with depth. PCA revealed three distinct depth-dependent water bodies in both multilevel profiles, which were found to be shifted vertically between the sampling events. This shift cut across a clayey bed which separated between the top and intermediate water bodies in the first profile, and was located entirely within the intermediate water body in the second profile. Continuous Electrical Conductivity (EC) monitoring in a packed off section of the observation well revealed an event in which a distinct water body flowed through the monitored section (v ∼ 150 m yr−1). Compilation of the aforementioned data and analysis lead to a conclusion that the observed changes in the profiles resulted from dominantly lateral flow of water bodies in the aquifer rather than vertical flow. The significance of this study is twofold: (a) it demonstrates the utility of sequential multilevel observations from deep wells and the efficacy of PCA for evaluating this data. (b) The fact that distinct water bodies of 10–100 m vertical and horizontal dimensions flow under contaminated sites has implications for monitoring and remediation.
45
von Storch, Jin-Song, Hideharu Sasaki et Jochem Marotzke. « Wind-Generated Power Input to the Deep Ocean : An Estimate Using a 1/10° General Circulation Model ». Journal of Physical Oceanography 37, no 3 (1 mars 2007) : 657–72. http://dx.doi.org/10.1175/jpo3001.1.
Texte intégralRésumé :
Abstract Recent studies on the wind-generated power input to the geostrophic and nongeostrophic ocean circulation components have used expressions derived from Ekman dynamics. The present work extends and unifies previous studies by deriving an expression from the kinetic energy budget of the upper layer based on the primitive equations. Using this expression, the wind-generated power available to the deep ocean is estimated from an integration with the 1/10° ocean general circulation model of the Earth Simulator Center. The result shows that the total power generated by the wind at the sea surface is about 3.8 TW. About 30% of this power (1.1 TW) is passed through a surface layer of about 110-m thickness to the ocean beneath. Approximating the wind-generated power to the deep ocean using Ekman dynamics produces two large errors of opposite signs, which cancel each other to a large extent.
46
Cuevas del Valle, Sergio, Hodei Urrutxua, Pablo Solano-López, Roger Gutierrez-Ramon et Ahmed Kiyoshi Sugihara. « Relative Dynamics and Modern Control Strategies for Rendezvous in Libration Point Orbits ». Aerospace 9, no 12 (5 décembre 2022) : 798. http://dx.doi.org/10.3390/aerospace9120798.
Texte intégralRésumé :
Deep space missions are recently gaining increasing interest from space agencies and industry, their maximum exponent being the establishment of a permanent station in cis-lunar orbit within this decade. To that end, autonomous rendezvous and docking in multi-body dynamical environments have been defined as crucial technologies to expand and maintain human space activities beyond near Earth orbit. Based on analytical and numerical formulations of the relative dynamics in the Circular Restricted Three Body Problem (CR3BP), a family of optimal, linear and nonlinear, continuous and impulsive, guidance and control techniques are developed for the design of end-to-end rendezvous trajectories between co-orbiting spacecraft in this multi-body dynamical environment. To this end, several modern control techniques are effectively designed and adapted to this problem, with particular emphasis on the design of low cost rendezvous manoeuvres. Finally, the designed hybrid rendezvous strategies, combining both discrete and continuous control techniques, are effectively tested and validated under several start-to-end deep space testbench mission scenarios, where their performance is compared and quantitatively assessed with a set of performance indices.
47
Wookey, James, et David P. Dobson. « Between a rock and a hot place : the core–mantle boundary ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 366, no 1885 (25 septembre 2008) : 4543–57. http://dx.doi.org/10.1098/rsta.2008.0184.
Texte intégralRésumé :
The boundary between the rocky mantle and iron core, almost 2900 km below the surface, is physically the most significant in the Earth's interior. It may be the terminus for subducted surface material, the source of mantle plumes and a control on the Earth's magnetic field. Its properties also have profound significance for the thermochemical and dynamic evolution of the solid Earth. Evidence from seismology shows that D″ (the lowermost few hundred kilometres of the mantle) has a variety of anomalous features. Understanding the origin of these observations requires an understanding of the elastic and deformation properties of the deep Earth minerals. Core–mantle boundary pressures and temperatures are achievable in the laboratory using diamond anvil cell (DAC) apparatus. Such experiments have led to the recent discovery of a new phase, ‘post-perovskite’, which may explain many hitherto poorly understood properties of D″. Experimental work is also done using analogue minerals at lower pressures and temperatures; these circumvent some of the limits imposed by the small sample size allowed by the DAC. A considerable contribution also comes from theoretical methods that provide a wealth of otherwise unavailable information, as well as verification and refinement of experimental results. The future of the study of the lowermost mantle will involve the linking of the ever-improving seismic observations with predictions of material properties from theoretical and experimental mineral physics in a quantitative fashion, including simulations of the dynamics of the deep Earth. This has the potential to dispel much of the mystery that still surrounds this remote but important region.
48
МИХАЙЛОВ, П. Г., Ж. У. ЖУБАНДЫКОВА et А. А. ТУКИБАЙ. « ЖЕР ҚҰРЫЛЫСЫНА ГЕОЭКОЛОГИЯЛЫҚ ЗЕРТТЕУЛЕР ЖҮРГІЗУ ТӘСІЛДЕРІ ». Industrial transport of Kazakhstan, no 2(75) (14 juin 2022) : 123–29. http://dx.doi.org/10.58420/itk.2022.75.2.010.
Texte intégralRésumé :
Приводятся результаты многолетних исследований. Совместно с сотрудниками лаборатории глубинного геологического строения и динамики литосферы была построена цифровая модель рельефа земли. Көпжылдық зерттеулердің нәтижелері келтірілген. Литосфераның терең геологиялық құрылымы мен динамикасы зертханасының қызметкерлерімен бірге жер бедерінің цифрлық моделі салынды. The results of many years of research are presented. Together with the staff of the Laboratory of deep geological structure and Dynamics of the lithosphere, a digital model of the relief of the earth was built.
49
Chen, Yurong, Feng Zhang, Xinba Li, Chuanrong Zhang, Ninghua Chen, Zhenhong Du, Renyi Liu et Bo Wang. « Deep Understanding of Urban Dynamics from Imprint Urban Toponymic Data Using a Spatial–Temporal–Semantic Analysis Approach ». ISPRS International Journal of Geo-Information 10, no 5 (28 avril 2021) : 278. http://dx.doi.org/10.3390/ijgi10050278.
Texte intégralRésumé :
Urban land use is constantly changing via human activities. These changes are recorded by imprint data. Traditionally, urban dynamics studies focus on two-dimensional spatiotemporal analysis. Based on our best knowledge, there is no study in the literature that uses imprint data for better understanding urban dynamics. In this research, we propose a spatial–temporal–semantic triple analytical framework to better understand urban dynamics by making full use of the imprint data, toponyms. The framework includes a text classification method and geographical analysis methods to understand urban dynamics in depth. Based on the inherent temporal and spatial information, we enrich semantic information with street names to explain urban dynamics in multiple dimensions. Taking Hangzhou city as an example, we used street names to reproduce the city changes over the past century. The results obtained through analysis of street names may accurately reflect the real development process of Hangzhou. This research demonstrates that imprint data left by urban development may play a pivotal role in better understanding urban dynamics.
50
Bar-On, Yinon M., Rob Phillips et Ron Milo. « The biomass distribution on Earth ». Proceedings of the National Academy of Sciences 115, no 25 (21 mai 2018) : 6506–11. http://dx.doi.org/10.1073/pnas.1711842115.
Texte intégralRésumé :
A census of the biomass on Earth is key for understanding the structure and dynamics of the biosphere. However, a global, quantitative view of how the biomass of different taxa compare with one another is still lacking. Here, we assemble the overall biomass composition of the biosphere, establishing a census of the ≈550 gigatons of carbon (Gt C) of biomass distributed among all of the kingdoms of life. We find that the kingdoms of life concentrate at different locations on the planet; plants (≈450 Gt C, the dominant kingdom) are primarily terrestrial, whereas animals (≈2 Gt C) are mainly marine, and bacteria (≈70 Gt C) and archaea (≈7 Gt C) are predominantly located in deep subsurface environments. We show that terrestrial biomass is about two orders of magnitude higher than marine biomass and estimate a total of ≈6 Gt C of marine biota, doubling the previous estimated quantity. Our analysis reveals that the global marine biomass pyramid contains more consumers than producers, thus increasing the scope of previous observations on inverse food pyramids. Finally, we highlight that the mass of humans is an order of magnitude higher than that of all wild mammals combined and report the historical impact of humanity on the global biomass of prominent taxa, including mammals, fish, and plants.