The Proceedings of the Fourth Chinese - German Joint Symposium 2008, contain various research art... more The Proceedings of the Fourth Chinese - German Joint Symposium 2008, contain various research articles on Hydraulic, Coastal and Ocean Engineering topics from the participant countries. The proceedings of the preceending Symposia are available as well at the above indicated website.
Die Abb. 1.6 zeigt den unteren Schleusenvorhafen der Schleuse Faulbach. Abbildung 1.6: Blick aus ... more Die Abb. 1.6 zeigt den unteren Schleusenvorhafen der Schleuse Faulbach. Abbildung 1.6: Blick aus dem unteren Schleusenvorhafen Staustufe Faulbach (Blickrichtung unterstrom) Am Ende der Trennmole wurde auch ein Durchbruch mit einem Staukopf errichtet. Abb. 1.7 zeigt den Staukopf von oberstrom aus gesehen. Die Trennmole, so wie sie in Abb. 1.7 zu sehen ist, ist über die ganze sichtbare Länge mit fünf Kammern durchbrochen. Die auf der Abb. 1.7 zu sehende rohrförmige Tauchwand ist unterhalb der Wasseroberfläche durchlässig und dient dazu, Treibsel aus der Hafenausfahrt fernzuhalten. Abbildung 1.7: Ansicht des Staukopfs von oberstrom Schleuse Faulbach Genaue Angaben über die Verringerung der Baggermengen infolge des Durchbruchs liegen weder aus Faulbach noch von Offenbach vor.
Irena, Mandica and Senka In memory of my father, Petar Vorwort Luftströmungen erzeugen in Gewässe... more Irena, Mandica and Senka In memory of my father, Petar Vorwort Luftströmungen erzeugen in Gewässern Oberflächenwellen. Je stärker die Windgeschwindigkeit und je länger die Wirkstrecke des Windes sind, desto höher und länger werden die Wellen. Da entlang der Streichlänge des Windes überall neue Wellen erzeugt werden, existiert an jedem Ort ein Spektrum an Wellen, die je nach Richtungskonstanz des Windes auch noch eine Bandbreite der Laufrichtungen aufweisen. Man spricht dann von Seegang. Die Kenntnis des Seegangs und seine Vorhersage sind für die Schifffahrt und die Küstenräume von herausragender Bedeutung. Da Wellen bis in eine Wassertiefe entsprechend der halben Wellenlänge wirken, kann der Seegang Grundberührung haben und sich im Zusammenwirken mit der lokalen Topographie des Meeresbodens verformen. Er kann dann auch Sedimente am Meeresgrund in Bewegung setzen und morphologische Veränderungen hervorrufen. Weiterhin belastet der Seegang die Küstenschutzbauwerke sowie die Dünen der küstenvorgelagerten Inseln. Diese Auswirkungen des Seegangs betreffen die Sicherheit der im Küstenraum lebenden Menschen. Diese Sicherheit zu gewährleisten, ist Aufgabe des Küsteningenieurwesens innerhalb des Bauingenieurwesens. Für Planung und Herstellung einerseits sicherer und andererseits wirtschaftlicher Schutzmaßnahmen sind Analysen und Prognosen der Seegangswirkung unumgänglich. Aussagen über die Entstehung und Ausbildung des Seegangs auf der offenen See sowie seine Verformung im flachen Küstenvorfeld einschließlich der Auswirkungen des Seegangs auf die Tideströmungen und die Sedimentbewegungen sind nur mit numerischen Modellen möglich. An dieser Stelle setzt die Dissertation von Dipl.-Ing. Aron Roland an. Dabei mußte er nicht "von Null" aus anfangen, sondern konnte auf die an der National Cheng Kung Universität in Tainan, Taiwan, begonnene Modellentwicklung WWM (WindWaveModel oder WindWellenModell) zur Vorhersage des Seegangs unter Taifunen zurückgreifen. Dieses Modell, hier als WWM I bezeichnet, war zu Beginn der Arbeit von Herrn Roland für eine Anwendung z.B. im deutschen Küstenraum nicht brauchbar, weil es aufgrund der erzielbaren Rechengeschwindigkeiten viel zu wenige Rechenpunkte erlaubte. Außerdem war die eingebaute Physik auf die Tiefwassergegebenheiten an der Pazifikseite von Taiwan abgestellt und nicht befriedigend gut für die flachen und komplex gestalteten Rinnensysteme unserer Küsten anwendbar. Herr Roland hat auf der Grundlage von WWM I das erheblich weitergehende Modell WWM II entwickelt, das derzeit weltweit zur Spitze der Seegangsmodelle gehört und schon jetzt von mehreren internationalen Entwicklergruppen angefragt wird.
Abstract: The atmosphere and the sea form a coupled system, exchanging momentum, heat and water a... more Abstract: The atmosphere and the sea form a coupled system, exchanging momentum, heat and water at their interface. In that exchange an important role is played by the surface waves and their interaction with surface currents. In this study an implementation of the Regional Ocean Modelling System (ROMS) coupled with the WWMII (Wind Wave Model II) model is used as the computational platform for exploration of related issues. We have designed our coupling library that allows to efficiently couple MPI based model based on ...
In this paper, the numerical framework for a freely available fully coupled wave-current model, w... more In this paper, the numerical framework for a freely available fully coupled wave-current model, which solves the Shallow Water and the Wave Action Equation (WAE) on unstructured meshes in geographical space and some first applications are presented. It consists of the hydrodynamic model SHYFEM (Shallow Water Hydrodynamic Finite Elements Model), and the 3rd generation spectral wave model WWM (Wind Wave Model). The application of numerical schemes on unstructured meshes renders the coupled model more efficient in resolving the model domain, the bathymetry and the involved gradient fields of currents, water levels and wave action. The source codes of the models have been coupled using FIFO (First In First Out pipes) data files. This technique makes an effective model coupling possible without cumbersome merging of both codes. Furthermore, it gives both source codes a universal interface for coupling with other flow or wave models. The coupled model was applied to simulate extreme events occurring in the Gulf of Mexico and the Adriatic Sea. In particular the wind and wave-induced storm surge generated by Hurricane Ivan was investigated and the results have been compared to the tidal gauge at Dauphin Island with reasonable results. For the case of the Adriatic Sea, the model, validated for the year 2004, has been applied to simulate waves and water levels induced by the century storm in November 1966 that lead to catastrophic and widespread damages in the regions of the Venice Lagoon. The obtained results have been compared to in situ measurements with respect to the wave heights and water level elevations revealing good accuracy of the model in reproduction of the investigated events. Especially, the Hurricane Ivan simulations showed the importance of inclusion of the wave-current interactions for the hindcast of the water levels during the storm surge. In a comparison to water level measurements at Dauphin Island, inclusion of the wave induced water level setup reduced the root mean square error from 0.13 to 0.11 m and increased the correlation coefficient from 0.75 to 0.79. For the case of the Venice Lagoon, the comparison with the measurements showed that the model without wave-current interactions led to a good hindcast of water levels for the location Punta Salute, which is located in the inner part of the Lagoon. Nevertheless, the comparison of subsequent simulations with and without the influence of the waves clearly showed a simulated effect of intense wave setup-up in the coastal area in front of the lagoon, which is plausible given the intensity of flooding that occurred there.
The first spectral numerical wave model was developed in the 1950s to deal with dispersive swell ... more The first spectral numerical wave model was developed in the 1950s to deal with dispersive swell propagation arriving in Morocco. These models are still being refined today, reaching typical root mean square errors of 10% on the significant wave height in the middle of oceans, an error level that has dropped 20% over the last 5 years, and 30% for the mean wave period. Errors in coastal areas are now getting close to these levels thanks to the introduction of currents, bottom sediment types, coastal reflection… These latter two aspects are particularly discussed here. Models are also getting more efficient with unstructured grids, allowing unprecedented detailed hindcasts and forecasts, such as provided by the Previmer and IOWAGA projects, and the estimate of new wave-related quantities such as air-sea fluxes, wave breaking statistics, acoustic and seismic noise sources… As these models are being pushed into shallower and shallower waters, the currents and water levels cannot be considered independently of waves. This has spurred an on-going effort on theoretical foundations, numerical techniques and measurement and validation methods for the investigation of coupled wave-current dynamics. We review here some of the important milestones in this effort and point to still open questions. As both authors have been strongly involved in the development of version 4 of the WAVEWATCH III model, soon to be made public, these are part of the ideas that have driven the development of this particular code, but they apply generally to all phase-averaged spectral models.
Egu General Assembly Conference Abstracts, May 1, 2014
The development of numerical wave models for coastal applications, including coupling with ocean ... more The development of numerical wave models for coastal applications, including coupling with ocean circulation models, has spurred an on-going effort on theoretical foundations, numerical techniques and physical parameterizations. Some important aspects of this effort are reviewed here, and results are shown in the case of the French Atlantic and Channel coast using version 4.18 of the WAVEWATCH III model. Compared to previously available implementations, the model errors have been strongly reduced thanks to, among other things, the introduction of currents, coastal reflection, and bottom sediment types. The model is particularly validated using SARAL-AltiKa data, which provides more accurate estimations of wave heights than previous Ku-band satellite altimeters. Including a wave model in a coupled modelling system puts more constraints on the required quality of the momentum fluxes passing through the wave field from the atmosphere to the ocean. Ongoing work to validate the wave impact on the wind stress will be reviewed, including the use of ECMWF's coupled atmosphere-wave IFS system.
CITATION 1 READS 135 10 authors, including: Some of the authors of this publication are also work... more CITATION 1 READS 135 10 authors, including: Some of the authors of this publication are also working on these related projects: coupled urban inundation sewage modelling -unrunoff-inka View project mean dynamic topography View project Luciana Fenoglio University Bonn/TU Darmstadt
CITATIONS 0 READS 53 1 author: Some of the authors of this publication are also working on these ... more CITATIONS 0 READS 53 1 author: Some of the authors of this publication are also working on these related projects: coupled urban inundation sewage modelling -unrunoff-inka View project
The discussion and the conclusions have focused on three main subjects: 1) coupling, 2) how to de... more The discussion and the conclusions have focused on three main subjects: 1) coupling, 2) how to deal with multiscale, 3) dangerous sea states. While by and large the group has followed this logical sequence, unavoidably the three subjects are, partly at least, interconnected. Therefore in the following discussion we will smoothly pass from one subject to another one with frequent crossreferences.
The development of numerical wave models for coastal applications, including coupling with ocean ... more The development of numerical wave models for coastal applications, including coupling with ocean circulation models, has spurred an on-going effort on theoretical foundations, numerical techniques and physical parameterizations. Some important aspects of this effort are reviewed here, and results are shown in the case of the French Atlantic and Channel coast using version 4.18 of the WAVEWATCH III R model. Compared to previous results, the model errors have been strongly reduced thanks to, among other things, the introduction of currents, coastal reflection, and bottom sediment types. This last item is described here for the first time, allowing unprecedented accuracy at some sites along the French Atlantic coast. The adequate resolution, necessary to represent strong gradients in tidal currents, was made possible by the efficiency brought by unstructured grids. A further increase in resolution, necessary to resolve surf zones and still cover vast regions, will require further developments in numerical methods.
The retrieval of the three geophysical parameters -sea surface height above the reference ellipso... more The retrieval of the three geophysical parameters -sea surface height above the reference ellipsoid (SSH), significant wave height (SWH) and wind speed at 10 meter above the sea surface (U10) -is the main goal of satellite altimetry and of primary importance for climate research. The Synthetic Aperture Radar (SAR) altimetry is expected to provide improved precision and along-track resolution compared to the conventional low-resolution mode (LRM) radar altimetry.
The Proceedings of the Fourth Chinese - German Joint Symposium 2008, contain various research art... more The Proceedings of the Fourth Chinese - German Joint Symposium 2008, contain various research articles on Hydraulic, Coastal and Ocean Engineering topics from the participant countries. The proceedings of the preceending Symposia are available as well at the above indicated website.
Die Abb. 1.6 zeigt den unteren Schleusenvorhafen der Schleuse Faulbach. Abbildung 1.6: Blick aus ... more Die Abb. 1.6 zeigt den unteren Schleusenvorhafen der Schleuse Faulbach. Abbildung 1.6: Blick aus dem unteren Schleusenvorhafen Staustufe Faulbach (Blickrichtung unterstrom) Am Ende der Trennmole wurde auch ein Durchbruch mit einem Staukopf errichtet. Abb. 1.7 zeigt den Staukopf von oberstrom aus gesehen. Die Trennmole, so wie sie in Abb. 1.7 zu sehen ist, ist über die ganze sichtbare Länge mit fünf Kammern durchbrochen. Die auf der Abb. 1.7 zu sehende rohrförmige Tauchwand ist unterhalb der Wasseroberfläche durchlässig und dient dazu, Treibsel aus der Hafenausfahrt fernzuhalten. Abbildung 1.7: Ansicht des Staukopfs von oberstrom Schleuse Faulbach Genaue Angaben über die Verringerung der Baggermengen infolge des Durchbruchs liegen weder aus Faulbach noch von Offenbach vor.
Irena, Mandica and Senka In memory of my father, Petar Vorwort Luftströmungen erzeugen in Gewässe... more Irena, Mandica and Senka In memory of my father, Petar Vorwort Luftströmungen erzeugen in Gewässern Oberflächenwellen. Je stärker die Windgeschwindigkeit und je länger die Wirkstrecke des Windes sind, desto höher und länger werden die Wellen. Da entlang der Streichlänge des Windes überall neue Wellen erzeugt werden, existiert an jedem Ort ein Spektrum an Wellen, die je nach Richtungskonstanz des Windes auch noch eine Bandbreite der Laufrichtungen aufweisen. Man spricht dann von Seegang. Die Kenntnis des Seegangs und seine Vorhersage sind für die Schifffahrt und die Küstenräume von herausragender Bedeutung. Da Wellen bis in eine Wassertiefe entsprechend der halben Wellenlänge wirken, kann der Seegang Grundberührung haben und sich im Zusammenwirken mit der lokalen Topographie des Meeresbodens verformen. Er kann dann auch Sedimente am Meeresgrund in Bewegung setzen und morphologische Veränderungen hervorrufen. Weiterhin belastet der Seegang die Küstenschutzbauwerke sowie die Dünen der küstenvorgelagerten Inseln. Diese Auswirkungen des Seegangs betreffen die Sicherheit der im Küstenraum lebenden Menschen. Diese Sicherheit zu gewährleisten, ist Aufgabe des Küsteningenieurwesens innerhalb des Bauingenieurwesens. Für Planung und Herstellung einerseits sicherer und andererseits wirtschaftlicher Schutzmaßnahmen sind Analysen und Prognosen der Seegangswirkung unumgänglich. Aussagen über die Entstehung und Ausbildung des Seegangs auf der offenen See sowie seine Verformung im flachen Küstenvorfeld einschließlich der Auswirkungen des Seegangs auf die Tideströmungen und die Sedimentbewegungen sind nur mit numerischen Modellen möglich. An dieser Stelle setzt die Dissertation von Dipl.-Ing. Aron Roland an. Dabei mußte er nicht "von Null" aus anfangen, sondern konnte auf die an der National Cheng Kung Universität in Tainan, Taiwan, begonnene Modellentwicklung WWM (WindWaveModel oder WindWellenModell) zur Vorhersage des Seegangs unter Taifunen zurückgreifen. Dieses Modell, hier als WWM I bezeichnet, war zu Beginn der Arbeit von Herrn Roland für eine Anwendung z.B. im deutschen Küstenraum nicht brauchbar, weil es aufgrund der erzielbaren Rechengeschwindigkeiten viel zu wenige Rechenpunkte erlaubte. Außerdem war die eingebaute Physik auf die Tiefwassergegebenheiten an der Pazifikseite von Taiwan abgestellt und nicht befriedigend gut für die flachen und komplex gestalteten Rinnensysteme unserer Küsten anwendbar. Herr Roland hat auf der Grundlage von WWM I das erheblich weitergehende Modell WWM II entwickelt, das derzeit weltweit zur Spitze der Seegangsmodelle gehört und schon jetzt von mehreren internationalen Entwicklergruppen angefragt wird.
Abstract: The atmosphere and the sea form a coupled system, exchanging momentum, heat and water a... more Abstract: The atmosphere and the sea form a coupled system, exchanging momentum, heat and water at their interface. In that exchange an important role is played by the surface waves and their interaction with surface currents. In this study an implementation of the Regional Ocean Modelling System (ROMS) coupled with the WWMII (Wind Wave Model II) model is used as the computational platform for exploration of related issues. We have designed our coupling library that allows to efficiently couple MPI based model based on ...
In this paper, the numerical framework for a freely available fully coupled wave-current model, w... more In this paper, the numerical framework for a freely available fully coupled wave-current model, which solves the Shallow Water and the Wave Action Equation (WAE) on unstructured meshes in geographical space and some first applications are presented. It consists of the hydrodynamic model SHYFEM (Shallow Water Hydrodynamic Finite Elements Model), and the 3rd generation spectral wave model WWM (Wind Wave Model). The application of numerical schemes on unstructured meshes renders the coupled model more efficient in resolving the model domain, the bathymetry and the involved gradient fields of currents, water levels and wave action. The source codes of the models have been coupled using FIFO (First In First Out pipes) data files. This technique makes an effective model coupling possible without cumbersome merging of both codes. Furthermore, it gives both source codes a universal interface for coupling with other flow or wave models. The coupled model was applied to simulate extreme events occurring in the Gulf of Mexico and the Adriatic Sea. In particular the wind and wave-induced storm surge generated by Hurricane Ivan was investigated and the results have been compared to the tidal gauge at Dauphin Island with reasonable results. For the case of the Adriatic Sea, the model, validated for the year 2004, has been applied to simulate waves and water levels induced by the century storm in November 1966 that lead to catastrophic and widespread damages in the regions of the Venice Lagoon. The obtained results have been compared to in situ measurements with respect to the wave heights and water level elevations revealing good accuracy of the model in reproduction of the investigated events. Especially, the Hurricane Ivan simulations showed the importance of inclusion of the wave-current interactions for the hindcast of the water levels during the storm surge. In a comparison to water level measurements at Dauphin Island, inclusion of the wave induced water level setup reduced the root mean square error from 0.13 to 0.11 m and increased the correlation coefficient from 0.75 to 0.79. For the case of the Venice Lagoon, the comparison with the measurements showed that the model without wave-current interactions led to a good hindcast of water levels for the location Punta Salute, which is located in the inner part of the Lagoon. Nevertheless, the comparison of subsequent simulations with and without the influence of the waves clearly showed a simulated effect of intense wave setup-up in the coastal area in front of the lagoon, which is plausible given the intensity of flooding that occurred there.
The first spectral numerical wave model was developed in the 1950s to deal with dispersive swell ... more The first spectral numerical wave model was developed in the 1950s to deal with dispersive swell propagation arriving in Morocco. These models are still being refined today, reaching typical root mean square errors of 10% on the significant wave height in the middle of oceans, an error level that has dropped 20% over the last 5 years, and 30% for the mean wave period. Errors in coastal areas are now getting close to these levels thanks to the introduction of currents, bottom sediment types, coastal reflection… These latter two aspects are particularly discussed here. Models are also getting more efficient with unstructured grids, allowing unprecedented detailed hindcasts and forecasts, such as provided by the Previmer and IOWAGA projects, and the estimate of new wave-related quantities such as air-sea fluxes, wave breaking statistics, acoustic and seismic noise sources… As these models are being pushed into shallower and shallower waters, the currents and water levels cannot be considered independently of waves. This has spurred an on-going effort on theoretical foundations, numerical techniques and measurement and validation methods for the investigation of coupled wave-current dynamics. We review here some of the important milestones in this effort and point to still open questions. As both authors have been strongly involved in the development of version 4 of the WAVEWATCH III model, soon to be made public, these are part of the ideas that have driven the development of this particular code, but they apply generally to all phase-averaged spectral models.
Egu General Assembly Conference Abstracts, May 1, 2014
The development of numerical wave models for coastal applications, including coupling with ocean ... more The development of numerical wave models for coastal applications, including coupling with ocean circulation models, has spurred an on-going effort on theoretical foundations, numerical techniques and physical parameterizations. Some important aspects of this effort are reviewed here, and results are shown in the case of the French Atlantic and Channel coast using version 4.18 of the WAVEWATCH III model. Compared to previously available implementations, the model errors have been strongly reduced thanks to, among other things, the introduction of currents, coastal reflection, and bottom sediment types. The model is particularly validated using SARAL-AltiKa data, which provides more accurate estimations of wave heights than previous Ku-band satellite altimeters. Including a wave model in a coupled modelling system puts more constraints on the required quality of the momentum fluxes passing through the wave field from the atmosphere to the ocean. Ongoing work to validate the wave impact on the wind stress will be reviewed, including the use of ECMWF's coupled atmosphere-wave IFS system.
CITATION 1 READS 135 10 authors, including: Some of the authors of this publication are also work... more CITATION 1 READS 135 10 authors, including: Some of the authors of this publication are also working on these related projects: coupled urban inundation sewage modelling -unrunoff-inka View project mean dynamic topography View project Luciana Fenoglio University Bonn/TU Darmstadt
CITATIONS 0 READS 53 1 author: Some of the authors of this publication are also working on these ... more CITATIONS 0 READS 53 1 author: Some of the authors of this publication are also working on these related projects: coupled urban inundation sewage modelling -unrunoff-inka View project
The discussion and the conclusions have focused on three main subjects: 1) coupling, 2) how to de... more The discussion and the conclusions have focused on three main subjects: 1) coupling, 2) how to deal with multiscale, 3) dangerous sea states. While by and large the group has followed this logical sequence, unavoidably the three subjects are, partly at least, interconnected. Therefore in the following discussion we will smoothly pass from one subject to another one with frequent crossreferences.
The development of numerical wave models for coastal applications, including coupling with ocean ... more The development of numerical wave models for coastal applications, including coupling with ocean circulation models, has spurred an on-going effort on theoretical foundations, numerical techniques and physical parameterizations. Some important aspects of this effort are reviewed here, and results are shown in the case of the French Atlantic and Channel coast using version 4.18 of the WAVEWATCH III R model. Compared to previous results, the model errors have been strongly reduced thanks to, among other things, the introduction of currents, coastal reflection, and bottom sediment types. This last item is described here for the first time, allowing unprecedented accuracy at some sites along the French Atlantic coast. The adequate resolution, necessary to represent strong gradients in tidal currents, was made possible by the efficiency brought by unstructured grids. A further increase in resolution, necessary to resolve surf zones and still cover vast regions, will require further developments in numerical methods.
The retrieval of the three geophysical parameters -sea surface height above the reference ellipso... more The retrieval of the three geophysical parameters -sea surface height above the reference ellipsoid (SSH), significant wave height (SWH) and wind speed at 10 meter above the sea surface (U10) -is the main goal of satellite altimetry and of primary importance for climate research. The Synthetic Aperture Radar (SAR) altimetry is expected to provide improved precision and along-track resolution compared to the conventional low-resolution mode (LRM) radar altimetry.
... Corresponding author address: Fabrice Ardhuin, Centre Militaire d'Océanographie, Service... more ... Corresponding author address: Fabrice Ardhuin, Centre Militaire d'Océanographie, Service Hydrographique et Océanographique de la Marine, 29609 Brest, France E-mail ... 2000), and swell dissipation (Ard-huin et al. 2008a), we use parameterizations based on Ardhuin et al. ...
Uploads
Books by Aron Roland
Papers by Aron Roland