A Numerical Framework for Modeling Folds in Structural Geology   总被引：1，自引：1，他引：0  

Øyvind Hjelle  Steen A. Petersen  Are Magnus Bruaset 《Mathematical Geosciences》2013,45(3):255-276

A numerical framework for modeling folds in structural geology is presented. This framework is based on a novel and recently published Hamilton–Jacobi formulation by which a continuum of layer boundaries of a fold is modeled as a propagating front. All the fold classes from the classical literature (parallel folds, similar folds, and other fold types with convergent and divergent dip isogons) are modeled in two and three dimensions as continua defined on a finite difference grid. The propagating front describing the fold geometry is governed by a static Hamilton–Jacobi equation, which is discretized by upwind finite differences and a dynamic stencil construction. This forms the basis of numerical solution by finite difference solvers such as fast marching and fast sweeping methods. A new robust and accurate scheme for initialization of finite difference solvers for the static Hamilton–Jacobi equation is also derived. The framework has been integrated in simulation software, and a numerical example is presented based on seismic data collected from the Karama Block in the North Makassar Strait outside Sulawesi.  相似文献   

The Paleo Heat Flow Contents in Vitrinite Reflectance Observations     

Magnus Wangen  Torbj?rn Throndsen  Gotskalk Halvorsen 《Mathematical Geology》2007,39(5):491-511

The heat flow content in vitrinite reflectance (VR) observations is studied based on a simple model of burial at a constant rate. The model is made dimensionless, and it has just one parameter except for the paleo heat flow. The question of existence and uniqueness of a solution is studied, and there exist in general no paleo heat flow that will reproduce a given VR-depth curve. But a solution is unique if it exists. A computed VR-depth function is shown to be smooth, even for piecewise constant heat flow histories. The paleo heat flow can be obtained from a VR-depth function after two times with derivations. It is also shown how the present day thermal gradient can be obtained by derivation of a VR-depth representation. The one-parameter model allows for approximate expressions for the optimal paleo heat flow as a step function. The results obtained from the one-parameter model is also compared with similar results from a real case study from the North Sea using a state-of-the-art basin simulator.  相似文献   

Pressure and temperature evolution in sedimentary basins   总被引：1，自引：0，他引：1  

Magnus Wangen 《Geophysical Journal International》1992,110(3):601-613

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Secondary migration of hydrocarbons in inclined layers     

Magnus Wangen 《Geophysical Journal International》1995,121(3):663-674

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Use of Microwave Radiances from Metop-C and Fengyun-3 C/DSatellites for a Northern European Limited-areaData Assimilation System     

Magnus LINDSKOG  Adam DYBBROE  Roger RANDRIAMAMPIANINA 《大气科学进展》2021,38(8):1415-1428

正1Swedish Meteorological and Hydrological Institute, Folkborgsv?gen 17, 60361 Norrk?ping, Sweden2Norwegian Meteorological Institute, Henrik Mohns Plass 1, 0371 Oslo, Norway  相似文献   

Worldwide status and perspective on gadoid culture   总被引：3，自引：2，他引：3  

Rosenlund  Grethe; Skretting  Magnus 《ICES Journal of Marine Science》2006,63(2):194-197

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Estimation of chlorophyll-a concentration in the Zhujiang Estuary from SeaWiFS data   总被引：1，自引：0，他引：1  

Chen Chuqun  Shi Ping  Magnus Larson  Lennart J&#;nsson 《海洋学报(英文版)》2002,21(1):55-65

The chlorophyll-a concentration is generally overestimated for the southern China coastalwaters if the default algorithm of the SeaDAS is employed. An algorithm is developed for retrieval of chlorophyll-a concentration in the Zhujiang Estuary, Guangdong Province, China, by using simulated reflectance data. The simulated reflectance is calculated corresponding to the SeaWiFS wavelength bands, via a general model by inputting measured water components, i.e. , the suspended sediment, chlorophyll-a, and yellow substance (DOC) concentration data of 130 samples. Empirical relationships of the chlorophyll-a concentration to 240 different band combinations are investigated based on the simulated reflectance data, and the band combination, R_5R_6/R_3R_4, is found to be the optimum one for the development of an algorithm valid for the Zhujiang Estuary. This algorithm is then employed to determine the chlorophyll-a concentration from SeaWiFS data. The estimated concentrations have a better accuracy than those obtai  相似文献   

Observation-based evaluation of surface wave effects on currents and trajectory forecasts   总被引：4，自引：2，他引：2  

Johannes R?hrs  Kai H?kon Christensen  Lars Robert Hole  G?ran Brostr?m  Magnus Drivdal  Svein Sundby 《Ocean Dynamics》2012,62(10-12):1519-1533

Knowledge of upper ocean currents is needed for trajectory forecasts and is essential for search and rescue operations and oil spill mitigation. This paper addresses effects of surface waves on ocean currents and drifter trajectories using in situ observations. The data set includes colocated measurements of directional wave spectra from a wave rider buoy, ocean currents measured by acoustic Doppler current profilers (ADCPs), as well as data from two types of tracking buoys that sample the currents at two different depths. The ADCP measures the Eulerian current at one point, as modelled by an ocean general circulation model, while the tracking buoys are advected by the Lagrangian current that includes the wave-induced Stokes drift. Based on our observations, we assess the importance of two different wave effects: (a) forcing of the ocean current by wave-induced surface fluxes and the Coriolis–Stokes force, and (b) advection of surface drifters by wave motion, that is the Stokes drift. Recent theoretical developments provide a framework for including these wave effects in ocean model systems. The order of magnitude of the Stokes drift is the same as the Eulerian current judging from the available data. The wave-induced momentum and turbulent kinetic energy fluxes are estimated and shown to be significant. Similarly, the wave-induced Coriolis–Stokes force is significant over time scales related to the inertial period. Surface drifter trajectories were analysed and could be reproduced using the observations of currents, waves and wind. Waves were found to have a significant contribution to the trajectories, and we conclude that adding wave effects in ocean model systems is likely to increase predictability of surface drifter trajectories. The relative importance of the Stokes drift was twice as large as the direct wind drag for the used surface drifter.  相似文献   

Application of a mass-balance model to predict PCDD/F turnover in a Baltic coastal estuary     

O. Magnus Karlsson  J. Mikael Malmaeus  Sarah Josefsson  Karin Wiberg  Lars Håkanson 《Estuarine, Coastal and Shelf Science》2010

A dynamical, process-based mass-balance model was applied to quantify the transports of polychlorinated-p-dibenzodioxins and dibenzofurans (PCDD/Fs) to, within and from the Kallrigafjärden Bay, a coastal estuary in the Baltic Sea, and to predict the PCDD/F levels in the water and sediments of the bay. Before the modelling, a one-year sampling programme was implemented in 2007–2008 to measure the flows of PCDD/Fs in tributaries entering the system, the fluxes from the adjacent sea and the levels in water, sediment and fish within the estuary. The collected data set was used as input data to the model and for validation purposes.  相似文献   

A numerical model of nearshore waves, currents, and sediment transport   总被引：1，自引：0，他引：1  

Pham Thanh Nam  Magnus Larson  Hans Hanson  Le Xuan Hoan   《Coastal Engineering》2009,56(11-12):1084-1096

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