Northern Gulf of Mexico continental slope   总被引：1，自引：0，他引：1  

Arnold H. Bouma  Harry H. Roberts 《Geo-Marine Letters》1990,10(4):177-181

The hummocky continental slope in the northwestern Gulf of Mexico is the result of active salt tectonism and accompanying faulting. Fluid and gassy hydrocarbons rise through the sediment column and along faults causing the formation of gas hydrates, gassy sediments, mud volcanoes and mounds, chemosynthetic communities and authigenic carbonates, reefs, and hardgrounds. Salt activity coupled with processes associated with relative sea level fluctuations create a feedback relationship resulting in the above-mentioned phenomena as well as others such as seafloor erosion at great water depths.  相似文献   

A simple formula for the estimation of pore pressures and their dissipation     

Arnold Verruijt 《Applied Ocean Research》1980,2(2):57-62

In the soil underneath a heavy structure pore water pressures may be generated by the loads on the structure. Such pore pressures lead to a reduction of the effective stresses, and therefore may influence the stability of the structure. The paper describes the mechanisms involved in the generation and dissipation of pore pressures. Analytical solutions of the complete problem are applicable only to very simple conditions, so that usually recourse has to be made to numerical methods. In order to check the validity of such solutions a simplified analytical method may be used. The establishment of such a simplified solution is illustrated in the paper. The approach provides the possibility of evaluating the influence of the various parameters involved in describing the problem. The simplified solution in principle applies to a wide class of three-dimensional problems, for which the progress of the consolidation process can be estimated.  相似文献   

On the coupling of uncoupled flow and transport solvers     

Fahmi Naifar  Peter Wilders  Arnold W. Heemink  Guus S. Stelling   《Estuarine, Coastal and Shelf Science》2007,74(4):732

The coupling of flow and transport solvers we are dealing with in this paper represents a whole intermediate processing step taking place between the two. We develop new techniques to ensure mass conservation of the transport while using totally different numerical schemes in the flow and in the transport solvers. We also present a method which allows the use of larger time steps for the transport computation than the one used for the flow leading therefore to faster computations and considerable reduction in disk space for the storage of flow data. These techniques are applied and tested in the numerical application of 2D and 3D problems.  相似文献   

Simultaneous calibration of surface flow and baseflow simulations: a revisit of the SWAT model calibration framework     

Xuesong Zhang  Raghavan Srinivasan  Jeff Arnold  R. Cesar Izaurralde  David Bosch 《水文研究》2011,25(14):2313-2320

Accurate analysis of water flow pathways from rainfall to streams is critical for simulating water use, climate change impact, and contaminants transport. In this study, we developed a new scheme to simultaneously calibrate surface flow (SF) and baseflow (BF) simulations of soil and water assessment tool (SWAT) by combing evolutionary multi‐objective optimization (EMO) and BF separation techniques. The application of this scheme demonstrated pronounced trade‐off of SWAT's performance on SF and BF simulations. The simulated major water fluxes and storages variables (e.g. soil moisture, evapotranspiration, and groundwater) using the multiple parameters from EMO span wide ranges. Uncertainty analysis was conducted by Bayesian model averaging of the Pareto optimal solutions. The 90% confidence interval (CI) estimated using all streamflows substantially overestimate the uncertainty of low flows on BF days while underestimating the uncertainty of high flows on SF days. Despite using statistical criteria calculated based on streamflow for model selection, it is important to conduct diagnostic analysis of the agreement of SWAT behaviour and actual watershed dynamics. The new calibration technique can serve as a useful tool to explore the trade‐off between SF and BF simulations and provide candidates for further diagnostic assessment and model identification. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Modification and testing of a one‐dimensional energy and mass balance model for supraglacial snowpacks     

Andrew M. Fox  Ian C. Willis  Neil S. Arnold 《水文研究》2008,22(16):3194-3209

A one‐dimensional energy and mass balance snow model (SNTHERM) has been modified for use with supraglacial snowpacks and applied to a point on Haut Glacier d'Arolla, Switzerland. It has been adapted to incorporate the underlying glacier ice and a site‐specific, empirically derived albedo routine. Model performance was tested against continuous measurements of snow depth and meltwater outflow from the base of the snowpack, and intermittent measurements of surface albedo and snowpack density profiles collected during the 1993 and 2000 melt seasons. Snow and ice ablation was simulated accurately. The timing of the daily pattern of meltwater outflow was well reproduced, although magnitudes were generally underestimated, possibly indicating preferential flow into the snowpack lysimeter. The model was used to assess the quantity of meltwater stored temporally within the unsaturated snowpack and meltwater percolation rates, which were found to be in agreement with dye tracer experiments undertaken on this glacier. As with other energy balance studies on alpine valley glaciers, the energy available for melt was dominated by net radiation (64%), with a sizable contribution from sensible heat flux (36%) and with a negligible latent heat flux overall, although there was more complex temporal variation on diurnal timescales. A basic sensitivity analysis indicated that melt rates were most sensitive to radiation, air temperature and snowpack density, indicating the need to accurately extrapolate/interpolate these variables when developing a spatially distributed framework for this model. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Change at the helm     

Arnold H. Bouma  Burg W. Flemming 《Geo-Marine Letters》1998,18(4):265-266

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Satellite laser ranging to GPS and GLONASS   总被引：5，自引：4，他引：1  

Krzysztof Sośnica  Daniela Thaller  Rolf Dach  Peter Steigenberger  Gerhard Beutler  Daniel Arnold  Adrian Jäggi 《Journal of Geodesy》2015,89(7):725-743

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CODE’s new solar radiation pressure model for GNSS orbit determination   总被引：10，自引：8，他引：2  

D. Arnold  M. Meindl  G. Beutler  R. Dach  S. Schaer  S. Lutz  L. Prange  K. Sośnica  L. Mervart  A. Jäggi 《Journal of Geodesy》2015,89(8):775-791

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Lagrangian modelling of multi-dimensional advection-diffusion with space-varying diffusivities: theory and idealized test cases     

Darya Spivakovskaya  Arnold W. Heemink  Eric Deleersnijder 《Ocean Dynamics》2007,57(3):189-203

To efficiently simulate the advection-diffusion processes along and across density surfaces, we need to deal with a diffusivity tensor containing off-diagonal elements (Redi, J Phys Oceanogr, 12:1154–1158, 1982). In the present paper, the Lagrangian model, in case of a space-varying diffusivity tensor, is developed. This random walk model is applied for two idealized test cases for which the analytical solutions are known. Results of the testing show that the Lagrangian approach provides accurate and effective solutions of advection-diffusion problems for general diffusivity tensor.  相似文献   

Gravimetric deflections of the vertical in high mountains determined by free-air anomalies     

K. Arnold 《Journal of Geodesy》1962,36(1):73-74

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