12 results on '"Quak, Ewald"'
Search Results
2. Topography, Hydrography, Circulation and Modelling of the Baltic Sea
- Author
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Soomere, Tarmo, Quak, Ewald, Myrberg, Kai, Lehmann, Andreas, Soomere, Tarmo, Quak, Ewald, Myrberg, Kai, and Lehmann, Andreas
- Abstract
The hydrography and dynamics of the Baltic Sea, although ruled by the same principles and forcing factors as any part of the World Ocean, contain several distinguishing features. Apart from the complicated geometry and bathymetry of the basin, two major factors contribute to the complexity of the processes here. The interplay between inflowing saline, dense waters from the North Sea in the bottom layer with the excess of light, and fresh riverine waters coming into the system in the upper layer leads to the formation of a permanent two-layer structure of density separated by a sharp jump layer (halocline). Due to the layered structure, the direct atmospheric forcing is restricted to the upper layer with a typical thickness of 40–80 m, while in the bottom layer advection and mixing processes govern the patterns of the hydrographic fields. On the top of the upper layer, a well-mixed surface layer, with a typical thickness of 15–20 m, is formed due to summer-time heating, whereas at the bottom of this layer a rather sharp jump layer of temperature (thermocline) exists. During autumn the vertical temperature gradient vanishes due to thermal convection and turbulent mixing. There are four mechanisms which induce currents in the Baltic Sea: the wind stress at the sea surface, the surface pressure gradient, the thermohaline horizontal gradient of density and the tidal forces. The currents are steered furthermore by the Coriolis acceleration, topography and friction, forming a general (cyclonic) circulation in this stratified system with positive fresh water budget. Due to the shallowness of the Baltic Sea, bottom friction damps the currents remarkably. Voluminous river runoffs can produce local changes in the sea level height and consequently also in currents. Inflowing waters penetrate at depths where the density of the ambient water matches the inflowing water masses. Due to the small baroclinic Rossby radius (2–10 km), the proper descriptions of mesoscale eddies, fronts
- Published
- 2013
3. Topography, Hydrography, Circulation and Modelling of the Baltic Sea
- Author
-
Soomere, Tarmo, Quak, Ewald, Myrberg, Kai, Lehmann, Andreas, Soomere, Tarmo, Quak, Ewald, Myrberg, Kai, and Lehmann, Andreas
- Abstract
The hydrography and dynamics of the Baltic Sea, although ruled by the same principles and forcing factors as any part of the World Ocean, contain several distinguishing features. Apart from the complicated geometry and bathymetry of the basin, two major factors contribute to the complexity of the processes here. The interplay between inflowing saline, dense waters from the North Sea in the bottom layer with the excess of light, and fresh riverine waters coming into the system in the upper layer leads to the formation of a permanent two-layer structure of density separated by a sharp jump layer (halocline). Due to the layered structure, the direct atmospheric forcing is restricted to the upper layer with a typical thickness of 40–80 m, while in the bottom layer advection and mixing processes govern the patterns of the hydrographic fields. On the top of the upper layer, a well-mixed surface layer, with a typical thickness of 15–20 m, is formed due to summer-time heating, whereas at the bottom of this layer a rather sharp jump layer of temperature (thermocline) exists. During autumn the vertical temperature gradient vanishes due to thermal convection and turbulent mixing. There are four mechanisms which induce currents in the Baltic Sea: the wind stress at the sea surface, the surface pressure gradient, the thermohaline horizontal gradient of density and the tidal forces. The currents are steered furthermore by the Coriolis acceleration, topography and friction, forming a general (cyclonic) circulation in this stratified system with positive fresh water budget. Due to the shallowness of the Baltic Sea, bottom friction damps the currents remarkably. Voluminous river runoffs can produce local changes in the sea level height and consequently also in currents. Inflowing waters penetrate at depths where the density of the ambient water matches the inflowing water masses. Due to the small baroclinic Rossby radius (2–10 km), the proper descriptions of mesoscale eddies, fronts
- Published
- 2013
- Full Text
- View/download PDF
4. Topography, Hydrography, Circulation and Modelling of the Baltic Sea
- Author
-
Soomere, Tarmo, Quak, Ewald, Myrberg, Kai, Lehmann, Andreas, Soomere, Tarmo, Quak, Ewald, Myrberg, Kai, and Lehmann, Andreas
- Abstract
The hydrography and dynamics of the Baltic Sea, although ruled by the same principles and forcing factors as any part of the World Ocean, contain several distinguishing features. Apart from the complicated geometry and bathymetry of the basin, two major factors contribute to the complexity of the processes here. The interplay between inflowing saline, dense waters from the North Sea in the bottom layer with the excess of light, and fresh riverine waters coming into the system in the upper layer leads to the formation of a permanent two-layer structure of density separated by a sharp jump layer (halocline). Due to the layered structure, the direct atmospheric forcing is restricted to the upper layer with a typical thickness of 40–80 m, while in the bottom layer advection and mixing processes govern the patterns of the hydrographic fields. On the top of the upper layer, a well-mixed surface layer, with a typical thickness of 15–20 m, is formed due to summer-time heating, whereas at the bottom of this layer a rather sharp jump layer of temperature (thermocline) exists. During autumn the vertical temperature gradient vanishes due to thermal convection and turbulent mixing. There are four mechanisms which induce currents in the Baltic Sea: the wind stress at the sea surface, the surface pressure gradient, the thermohaline horizontal gradient of density and the tidal forces. The currents are steered furthermore by the Coriolis acceleration, topography and friction, forming a general (cyclonic) circulation in this stratified system with positive fresh water budget. Due to the shallowness of the Baltic Sea, bottom friction damps the currents remarkably. Voluminous river runoffs can produce local changes in the sea level height and consequently also in currents. Inflowing waters penetrate at depths where the density of the ambient water matches the inflowing water masses. Due to the small baroclinic Rossby radius (2–10 km), the proper descriptions of mesoscale eddies, fronts
- Published
- 2013
- Full Text
- View/download PDF
5. Topography, Hydrography, Circulation and Modelling of the Baltic Sea
- Author
-
Soomere, Tarmo, Quak, Ewald, Myrberg, Kai, Lehmann, Andreas, Soomere, Tarmo, Quak, Ewald, Myrberg, Kai, and Lehmann, Andreas
- Abstract
The hydrography and dynamics of the Baltic Sea, although ruled by the same principles and forcing factors as any part of the World Ocean, contain several distinguishing features. Apart from the complicated geometry and bathymetry of the basin, two major factors contribute to the complexity of the processes here. The interplay between inflowing saline, dense waters from the North Sea in the bottom layer with the excess of light, and fresh riverine waters coming into the system in the upper layer leads to the formation of a permanent two-layer structure of density separated by a sharp jump layer (halocline). Due to the layered structure, the direct atmospheric forcing is restricted to the upper layer with a typical thickness of 40–80 m, while in the bottom layer advection and mixing processes govern the patterns of the hydrographic fields. On the top of the upper layer, a well-mixed surface layer, with a typical thickness of 15–20 m, is formed due to summer-time heating, whereas at the bottom of this layer a rather sharp jump layer of temperature (thermocline) exists. During autumn the vertical temperature gradient vanishes due to thermal convection and turbulent mixing. There are four mechanisms which induce currents in the Baltic Sea: the wind stress at the sea surface, the surface pressure gradient, the thermohaline horizontal gradient of density and the tidal forces. The currents are steered furthermore by the Coriolis acceleration, topography and friction, forming a general (cyclonic) circulation in this stratified system with positive fresh water budget. Due to the shallowness of the Baltic Sea, bottom friction damps the currents remarkably. Voluminous river runoffs can produce local changes in the sea level height and consequently also in currents. Inflowing waters penetrate at depths where the density of the ambient water matches the inflowing water masses. Due to the small baroclinic Rossby radius (2–10 km), the proper descriptions of mesoscale eddies, fronts
- Published
- 2013
- Full Text
- View/download PDF
6. Patterns of current-induced transport in the surface layer of the Gulf of Finland
- Author
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Soomere, Tarmo, Delpeche, Nicole, Viikmaee, Bert, Quak, Ewald, Meier, H. E. Markus, Döös, Kristofer, Soomere, Tarmo, Delpeche, Nicole, Viikmaee, Bert, Quak, Ewald, Meier, H. E. Markus, and Döös, Kristofer
- Abstract
The Lagrangian trajectory model TRACMASS based on an Eulerian field of velocities (calculated using the Rossby Centre Ocean Model), combined with relevant statistical analysis, is used for the identification of transport patterns in the surface layer of the Gulf of Finland from 1987-1991. The analysis of velocity fields and properties of net and bulk transport (the distance between the start and end positions of a trajectory, and the total length of the trajectory, respectively) shows the presence of semi-persistent (with a typical lifetime from a week to a few months) features of the surface-layer dynamics, a part of which evidently cannot be extracted directly from the velocity fields. The modelled surface dynamics mostly hosts an Ekman-type drift and, in yearly average, contains an anticyclonic gyre occupying the western part of the gulf. The prevailing transport directions to the east and slightly to the south match the direction of the Ekman surface drift created by predominant south-western winds. The spatial patterns of the net transport substantially vary over different seasons. The most intense net transport along the coasts occurs in the western and central parts of the gulf but contains relatively intense largely meridional transport pathways in some seasons., authorCount :6
- Published
- 2011
7. Data fitting by wavelet shrinkage using GM-waves
- Author
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Moguchaya, T. N., Gundersen, J., Grip, Niklas, Dechevsky, L.T., Bang, B., Lakså, A., Quak, Ewald, Tong, B., Moguchaya, T. N., Gundersen, J., Grip, Niklas, Dechevsky, L.T., Bang, B., Lakså, A., Quak, Ewald, and Tong, B.
- Abstract
We present a new wavelet software system, GM-Waves, and illustrate some of its features in the context of the study of methods for wavelet shrinkage and their application to curve and surface fitting, smoothing and denoising by wavelets., Godkänd; 2005; 20071214 (ysko)
- Published
- 2005
8. Data fitting by wavelet shrinkage using GM-waves
- Author
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Moguchaya, T. N., Gundersen, J., Grip, Niklas, Dechevsky, L.T., Bang, B., Lakså, A., Quak, Ewald, Tong, B., Moguchaya, T. N., Gundersen, J., Grip, Niklas, Dechevsky, L.T., Bang, B., Lakså, A., Quak, Ewald, and Tong, B.
- Abstract
We present a new wavelet software system, GM-Waves, and illustrate some of its features in the context of the study of methods for wavelet shrinkage and their application to curve and surface fitting, smoothing and denoising by wavelets., Godkänd; 2005; 20071214 (ysko)
- Published
- 2005
9. An Example Concerning the L (sub p)-Stability of Piecewise Linear B-Wavelets
- Author
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TARTU UNIV (ESTONIA) DEPT OF MATHEMATICS, Oja, Peeter, Quak, Ewald, TARTU UNIV (ESTONIA) DEPT OF MATHEMATICS, Oja, Peeter, and Quak, Ewald
- Abstract
In this paper we consider B-wavelets of order 2, i.e. piecewise linear spline prewavelets of smallest support, over nonuniform knot sequences. We discuss an example showing that for 1 is less than p is less than or equal to infinity, there is no absolute L(sub p)-stability for these B-wavelets. This means that regardless what specific scaling of the B-wavelets is chosen, the corresponding stability constants cannot be made independent of the knot sequences involved., The original document contains color images. All DTIC reproductions will be in black and white. Presented at Algorithms for Approximation IV held in Huddersfield, UK on 16-20 Jul 2001. This article is from ADA412833 Algorithms For Approximation IV. Proceedings of the 2001 International Symposium
- Published
- 2001
10. The evolution and testing of a medium sized numerical package
- Author
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Langtangen, Hans Petter, Bruaset, Are Magnus, Quak, Ewald, Barnes, David J., Hopkins, Tim, Langtangen, Hans Petter, Bruaset, Are Magnus, Quak, Ewald, Barnes, David J., and Hopkins, Tim
- Abstract
We investigate the evolution of a medium sized software package, LAPACK, through its public releases over the last six years and establish a correlation, at a subprogram level, between a simply computable software metric value and the number of coding errors detected in the released routines. We also quantify the code changes made between issues of the package and attempt to categorize the reasons for these changes. We then consider the testing strategy used with LAPACK. Currently this consists of a large number of mainly self-checking driver programs along with sets of configuration files. These suites of test codes run a very large number of test cases and consume significant amounts of cpu time. We attempt to quantify how successful this testing strategy is from the viewpoint of the coverage of the executable statements within the routines being tested.
- Published
- 2000
11. The Evolution and Testing of a Medium Sized Numerical Package
- Author
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Langtangen, Hans Petter, Bruaset, Are Magnus, Quak, Ewald, Barnes, David J., Hopkins, Tim, Langtangen, Hans Petter, Bruaset, Are Magnus, Quak, Ewald, Barnes, David J., and Hopkins, Tim
- Abstract
We investigate the evolution of a medium sized software package, sc LAPACK, through its public releases over the last six years and establish a correlation, at a subprogram level, between a simply computable software metric value and the number of coding errors detected in the released routines. We also quantify the code changes made between issues of the package and attempt to categorize the reasons for these changes. We then consider the testing strategy used with sc LAPACK. Currently this consists of a large number of mainly self-checking driver programs along with sets of configuration files. These suites of test codes run a very large number of test cases and consume significant amounts of cpu time. We attempt to quantify how successful this testing strategy is from the viewpoint of the coverage of the executable statements within the routines being tested.
- Published
- 2000
12. Editorial
- Author
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Magnenat-Thalmann, Nadia, Quak, Ewald, Magnenat-Thalmann, Nadia, and Quak, Ewald
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