The Western Irish Namurian Basin reassessed – a discussion     

Ole J. Martinsen  John D. Collinson 《Basin Research》2002,14(4):523-542

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IAG Newsletter     

Ole Baltazar Andersen 《Journal of Geodesy》2001,74(11-12):823-825

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IAG Newsletter     

Ole Baltazar Andersen 《Journal of Geodesy》2001,75(7-8):450-455

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Effects of asthenospheric heat flow in basin modelling exemplified with the Danish Basin     

Ole Valdemar Vejbk 《Earth and Planetary Science Letters》1989,95(1-2)

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Mapping the shape, size, and density of fish schools by echo integration and a high-resolution sonar   总被引：1，自引：0，他引：1  

Misund  Ole Arve; Aglen  Asgeir; Fronaes  Erik 《ICES Journal of Marine Science》1995,52(1):11-20

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Constraining Surface Interpolations Using Elastic Plate Bending Solutions with Applications to Geologic Folding   总被引：3，自引：2，他引：1  

J. Ole Kaven  Rafe Mazzeo  David D. Pollard 《Mathematical Geosciences》2009,41(1):1-14

Geologic surface interpolations can be augmented by adding physical constraints to available data. Here a method is outlined that allows one to constrain surface interpolations for two geologic surfaces based on the apparent thickness of the bounded layer. The resulting interpolation scheme is posed as a quadratic programming in which the interpolation of each surface is solved approximately and subject to linear constraints on the apparent thickness. Results can be further improved by adding cubic polynomials to the interpolating functions to regularize the problem. In one-dimensional interpolations of geologic folds, the method improves the results over unconstrained interpolations by eliminating interpenetrations (negative apparent thicknesses) and regions of small apparent thicknesses. In a two-dimensional application for the monocline at Raplee Ridge, UT, the capability of this method is illustrated by overcoming interpenetration of two surfaces, the tops of the Mendenhall oil sand and the Unnamed limestone. The minimum curvature spline interpolation is applied to topographic data taken from an airborne laser swath mapping (ALSM) survey and interpolated by detailed geologic mapping. This method can be extended to allow for multiple layers.  相似文献   

Impact of GODAE products on nested HYCOM simulations of the West Florida Shelf     

George R. HalliwellJr  Alexander Barth  Robert H. Weisberg  Patrick Hogan  Ole Martin Smedstad  James Cummings 《Ocean Dynamics》2009,59(1):139-155

Nested non-assimilative simulations of the West Florida Shelf for 2004–2005 are used to quantify the impact of initial and boundary conditions provided by Global Ocean Data Assimilation Experiment ocean products. Simulations are nested within an optimum interpolation hindcast of the Atlantic Ocean, the initial test of the US Navy Coupled Ocean Data Assimilation system for the Gulf of Mexico, and a global ocean hindcast that used the latter assimilation system. These simulations are compared to one that is nested in a non-assimilative Gulf of Mexico model to document the importance of assimilation in the outer model. Simulations are evaluated by comparing model results to moored Acoustic Doppler Current Profiler measurements and moored sea surface temperature time series. The choice of outer model has little influence on simulated velocity fluctuations over the inner and middle shelf where fluctuations are dominated by the deterministic wind-driven response. Improvement is documented in the representation of alongshore flow variability over the outer shelf, driven in part by the intrusion of the Loop Current and associated cyclones at the shelf edge near the Dry Tortugas. This improvement was realized in the simulation nested in the global ocean hindcast, the only outer model choice that contained a realistic representation of Loop Current transport associated with basin-scale wind-driven gyre circulation and the Atlantic Meridional Overturning Circulation. For temperature, the non-assimilative outer model had a cold bias in the upper ocean that was substantially corrected in the data-assimilative outer models, leading to improved temperature representation in the simulations nested in the assimilative outer models.  相似文献   

Computed tomography scan imaging of natural open fractures in a porous rock; geometry and fluid flow   总被引：2，自引：0，他引：2  

Ole Petter Wennberg  Lars Rennan  Remy Basquet 《Geophysical Prospecting》2009,57(2):239-249

Computed tomography scan imaging techniques have been used on core samples to investigate the effect of natural open fractures on reservoir flow in the Snøhvit Gas Condensate Field. Firstly, computed tomography (CT) scanning was used to describe the 3D geometrical properties of the fracture network including orientation and fracture density. Two types of fractures were observed: F1 fractures are short and stylolite related and F2 fractures are longer, cross-cutting the core and without any obvious relationship to stylolites. Secondly, monitoring of single and two phase flow experiments on samples containing these two types of natural open fractures was performed under 10 and 80 bar net confining pressure while using CT scanning. 1-phase miscible flooding experiment shows approximately 3 times higher flooding velocity in an open F2 fracture than in the matrix. 2-phase flooding by gas injection into a 100% water saturated core gave early gas breakthrough due to flow in the fracture and thereafter very little water production. The flow experiments showed that the presence of open fractures has a significant local effect on fluid flow even in a case with relatively high matrix porosity (200–300 mD). The sample containing F1 fractures showed a complex flow pattern influenced both by open fractures and stylolites. The CT scan data enables an exact representation of the fracture network in core scale simulation models and therefore improves the understanding of fracture influence on flow in a fractured porous medium. CT scanning of core samples provides an effective tool for integrating geology and fluid flow properties of a porous fractured medium.  相似文献   

Pedotransfer functions estimating soil hydraulic properties using different soil parameters   总被引：1，自引：0，他引：1  

Christen D. Børgesen  Bo V. Iversen  Ole H. Jacobsen  Marcel G. Schaap 《水文研究》2008,22(11):1630-1639

Estimates of soil hydraulic properties using pedotransfer functions (PTF) are useful in many studies such as hydrochemical modelling and soil mapping. The objective of this study was to calibrate and test parametric PTFs that predict soil water retention and unsaturated hydraulic conductivity parameters. The PTFs are based on neural networks and the Bootstrap method using different sets of predictors and predict the van Genuchten/Mualem parameters. A Danish soil data set (152 horizons) dominated by sandy and sandy loamy soils was used in the development of PTFs to predict the Mualem hydraulic conductivity parameters. A larger data set (1618 horizons) with a broader textural range was used in the development of PTFs to predict the van Genuchten parameters. The PTFs using either three or seven textural classes combined with soil organic mater and bulk density gave the most reliable predictions of the hydraulic properties of the studied soils. We found that introducing measured water content as a predictor generally gave lower errors for water retention predictions and higher errors for conductivity predictions. The best of the developed PTFs for predicting hydraulic conductivity was tested against PTFs from the literature using a subdata set of the data used in the calibration. The test showed that the developed PTFs gave better predictions (lower errors) than the PTFs from the literature. This is not surprising since the developed PTFs are based mainly on hydraulic conductivity data near saturation and sandier soils than the PTFs from the literature. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Improved prediction of vegetation composition in NW European softwater lakes by combining location,water and sediment chemistry     

Cristina?PulidoEmail author  Kaj?Sand-Jensen  Esther?C.?H.?E.?T.?Lucassen  Jan?G.?M.?Roelofs  Klaus?P.?Brodersen  Ole?Pedersen 《Aquatic Sciences - Research Across Boundaries》2012,74(2):351-360

Isoetids, as indicators of near-pristine softwater lakes, have a high priority in national and international (European Water Directive Framework) assessments of ecological lake quality. Our main goal was to identify the most important environmental factors that influence the composition of plant communities and specifically determine the presence and abundance of the isoetid Lobelia dortmanna in NW European softwater lakes. Geographical position and composition of surface water, porewater, sediment and plant communities were examined in 39 lakes in four regions (The Netherlands, Denmark, West Norway and East Norway) distributed over a 1,200-km long distance. We confirmed that lake location was accompanied by significant changes in environmental variables between NW European lakes. Lake location was the single most important determinant of vegetation composition and it had significant individual contributions independent of the coupling to environmental variables. This influence of location was supported by a significant decline of community similarity with geographical distance between pairs of lakes at regional, inter-regional and international scales. Combining the geographical position with environmental variables for surface water, porewater and sediment significantly improved prediction of vegetation composition. Specifically, the combination of latitude, surface water alkalinity, porewater phosphate and redox potential offered the highest correlation (BIO ENV correlation 0.66) to vegetation composition. This complex analysis can also account for high sediment variability in the littoral zone of individual lakes, by using site-specific physico-chemical sediment factors, and offer better predictions of vegetation composition when lake water chemistry is relatively homogeneous among lakes within regions.  相似文献