The department of Radar Hydrograhy is involved in several national and international projects. These projects a related to the development as well as application of radar remote sensing methods for getting a better understanding of surface and near surface processes.
Planned air-sea interface PIV (Particle Image Velocimetry) experiment, and lab results from Buckley and Veron, 2016 (upper right).
Air-sea fluxes of momentum, energy, heat and mass are crucial boundary conditions for weather, climate and oceanic motions These fluxes are affected by the complex dynamics at the ocean surface, and in particular by the interactions between the wind and surface waves. In order to understand the complex feedback mechanisms between waves and the airflow dynamics, we are developing novel experiment techniques, including air-sea interfacial PIV (Particle Image Velocimetry), to visualize, quantify and understand the turbulent kinematics that control air-sea fluxes. We will use the obtained observations as well as existing controlled laboratory measurements to parameterize air-sea fluxes and to validate novel coupled numerical wind-wave models.
Buckley and Veron, 2016
COSYNA - HF-Radars Monitoring of the German Bight
Map of ship tracks generated from the HF-radar data acquired in the German Bight.
Within the COSYNA project the department of Radar Hydrography operates three HF-radar systems along the German coast (Wangerooge, Buesum and Sylt). The radars are operated continuously and deliver a surface current field of the German Bight every 20 minutes. In addition the data are used to develop methodologies for ship detection tracking and fusion, which result in maps of ship tracks that are updated every 33 s. The later activity is performed in collaboration with the [url=http://www.cmre.nato.int/]Center for Maritime Research and Experimentation (CMRE)[/url, La Spezia, Italy.
Marine radar retrieved bathymetry in front of Bunkerhil, Sylt.
In addition the department operates 2 of their coherent marine radar systems at the island of Sylt and at the research platform Fino-3, located in the German Bight. The Sylt radar is utilized for testing the monitoring capability of radar retrieved bathymetry and the Fino-3 radar for retrieving currents and waves on an operational basis with HZGs radar tool ROWMS.
Fino-3 - Investigation of the Influence of Wind Farms on Sea State
HZG's coheren X-band marine radar mounted on the research platform Fino-3.
Within the Fino-3 Project the department is investigating the influence of the offshore wind parks on the climate of the surface waves. Therefore we are utilizing our X-band marine radar systems as well as different in situ devices available on the offshore platform Fino-3 as well as temporary moored equipment during the Heincke cruise (May, 2015). The Fino-3 project is funded by the German Federal Ministry for Economic Affairs and Energy (BMWi).
One objective within PACES II is the investigation of the influence of wind parks on the ocean dynamics. Therefore we developed measurement techniques to estimate the impact of ocean surface wind fields on the ocean surface utilizing marine radar imagery. Therefore we collected marine radar data during the Heincke cruise 445 passing through several wind parks as well as our marine radar located on Fino-3 in vicinity of the wind park DanTysk. Marine radars measure the small scale surface roughness of the ocean surface in space and time. We have developed methodologies to convert marine radar surface roughness to friction velocities and under most conditions also into surface wind fields. These measurements can be used to retrieve the change of the ocean dynamics due to the change of the local wind field by the wind farm.
Marine radar retrieved time series of the wind field in lee of the windfarm DanTysk measured at the research platform Fino-3. The impact of the turbines on the local wind field can be nicely observed by the turbulent wakes in lee of the turbines.
JericoNEXT - Improvement of HF-Radar Current and Wave Products
Current field resulting from the HF-radar network of the German Bight.
Within the HF-radar work packages of JericoNEXT the main objectives are:
- improvement of HF-radar current and wave retrieval algorithms with respect to strong spatial and temporal varying currents.
- development of an improved quality control resulting in maps with additional error flags with respect to the accuracy of surface currents.
JericoNEXT is funded by the European commission within the framework of Horizon 2020. For more information refer to JericoNEXT
WaveDiss - Ocean Surface Wave Dissipation
Wave driven processes in the coastal zone.
The near-shore wave field is strongly affected by the local sea-floor topography. Waves that are traveling over a complex, shallow bathymetry undergo a strong, nonlinear change of their shape and propagation dynamics until the water mass gets unstable and the waves break.
During wave breaking, the incoming wave energy is transferred to currents, turbulence and heat. These wave induced parameters act as the main drivers for the mobilization and transport of local sediments and therefore they are of major importance for an understanding of long-term changes of our coastlines.
Despite their high relevance, many of the processes involved in near-shore hydro- and morphodynamics are still poorly understood.
Within “WaveDiss” we work on methods to provide a continuous , remote mapping of the near-shore, bathymetry, wave field, wave breaking intensity and currents.
A consistent, long-term dataset of these quantities will open the opportunity to understand the near-shore hydrodynamics in a variety of different environmental conditions (e.g. different storm characteristics) and this may help to understand how the coastal zone is reacting to a change in climate conditions.
Lindesnes - Coherent Marine Radars for Measuring Sea State
HZG's coherent X-band marine radar system is operating since 17. January 2015 at the lighthouse of Lindesnes, Norway.
In this project the department is testing and improving their algorithms for wave retrieval using coherent marine radars. Therefore, a coherent marine radar is beeing operated at the lighthouse of Lindesnes, Norway since January 2015. The data are utilized to measure the spectral wave parameters (e.g. peak period, peak wave direction and significant wave height) as well as individual wave paraneters (e.g. wave height). These parameters will be compared to the meaurements of two bottom mounted Acoustic Wave and Current Profilers (AWACs). This project is funded by the Norwegian Reserach Council within a colaboration between NORTEK and the University of Oslo, Norway.