Hydrodynamik und Datenssimilation

Projekte

One important part of our work is the cooperation with other research institutes, public institutions and companies. We have participated in multiple national and international projects. Some of the current projects are described below.

Coastal unstructured resolution for aquatic environments

Project timeline: APR 2018 – MAR 2020

The main objective of CURAE is to prepare a new set of downscaling and coupling tools, which, based on present Copernicus - Marine environment monitoring service (CMEMS) products, will open a wide range of coastal applications and contribute to enhance the coastal dimensions. The core of the project is the incorporation of the coastal fringe as an active boundary layer, interacting bi-directionally with the shelf sea and including the continental discharge in terms of water, sediment and nutrient fluxes. To prove the feasibility of this approach two coastal pilots have been selected that feature river and irrigation discharges, dredging and their interactions. The selected sites also represent two contrasting environments (micro and macro tidal, low to high wave energy, mild though point wise torrential and medium to high precipitation rates) and two different numerical approaches for downscaling so that the derived conclusions and tools should be generic enough and of direct value for a CMEMS extension towards the coast.
Such a general aim and structure will be done trough: (i) introducing asymmetric interpolation and error assessment techniques as required by anisotropic coastal domains; (ii) assessing the different relative weights of processes and coupling in coastal areas, with respect to deep water oceanography, providing criteria and recommendations for the further evolution of the marine services; (iii) proving the feasibility of including some selected coastal interventions into the forecasting tools, to illustrate another coastal extension with high added value for specific applications and general land/water planning; (iv) promoting the use of unstructured grids , benefiting from the higher flexibility for distributing mesh nodes.

Consistent wave-mean flow modelling in coupled atmosphere-wave-ocean models

Project timeline: APR 2018 - MAR 2010

WaveFlow addresses the impact that unresolved wave-mean flow effects have on the circulation in the upper ocean. Specifically, the project aims to introduce recent improvements to the physical parameterizations of wave physics in a state-of-the-art wave model used for operational wave forecasting. The wave fields and fluxes will be implemented in an openly available wave model code and new processes tested with fields and fluxes from a decades-long wave hindcast of the soon to be completed ERA5 reanalysis studied. The tests will be carried out on scales, ranging from vertical column one-dimensional setups to regional, high-resolution models and all the way to global ocean-only and fully coupled atmosphere-wave-ocean forecast systems. The project aims to explore the beneficial impact on the predictability of forecast systems and the potential improvement to the circulation of the upper ocean. The project brings together a consortium with complementary competence on wave and ocean modelling and will lay novel foundations for how wave and ocean models should interact.

The CEASELESS project will demonstrate how the new Sentinel measurements can support the development of a coastal dimension in Copernicus by providing an unprecedented level of resolution / accuracy / continuity with respect to present products. The retrieval and validation for restricted domains and for an enlarged set of combined, user oriented variables will be the basis to advance the state of the art in assimilation, modelling and applications, at a level commensurate with the new Sentinel capabilities. The project will address the multiple scales coexisting in littoral areas by developing new shallow water parameterizations, introducing them into coupled model suites (wind-wave-surge-current-land discharge) and producing new standards for coastal simulations and analyses. The permanent data base, with dynamic repositories, plus the modular structure of the developed models will demonstrate the technical feasibility of a future operational Copernicus coastal service. The set of derived products will be ingested into the users’ work routines, proving the economic feasibility of the Copernicus coastal extension. The level of conflicts in squeezed coastal zones, expected to grow in the face of climate change, will, thus, benefit directly from CEASELESS, establishing tangible contributions for a wide range of economic sectors. The data repositories (accessible via a dedicated portal), regularly updated with the evolving (satellite-derived) bathymetry will facilitate the use/re-use of our high resolution results, supporting a new set of Copernicus coastal applications such as renewable energy, coastal erosion or harbor exploitation. The mutual validation of satellite data, numerical results and in-situ observations will generate reciprocal profit for enhanced competiveness of EU coastal industries where we shall also explore the suitability for cases in 3rd countries, opening new business opportunities for a coastal Copernicus.
HZG leads the work package entitled "Derived products / performances as proof-of-concept for a Copernicus coastal service".

Provision of ocean analysis and forecast products for the Black Sea

Project timeline: JAN 2018 – MAR 2021

Black Sea – Monitoring Forecasting Centre (BS MFC) contributes to the development of the COPERNICUS Marine Environment Monitoring Service (CMEMS). It provides regular and systematic information about the physical state of the ocean and marine ecosystems for the Black Sea. The system is based on a numerical ocean model assimilating in-situ and satellite data. BS MFC gathers expertise in the field of ocean analysis and forecast in the Black Sea, brings together knowledge of the regional Black Sea dynamics, and enhances technical links with other CMEMS components and strong connection with the other CMEMS MFCs. Moreover, BS MFC’s objectives include the planning and efficient implementation of systems upgrades. BS MFC provides marine data about the Black Sea such as analysis and 10 days forecasts and reanalysis, describing waves, currents, temperature, salinity, sea level and biogeochemistry. HZG is responsible for the Waves Physics Production Unit, including synergy between model and observational data as well assimilation of newly available data. HZG is also involved in coupling of waves and circulation models and system evolution.

WAVE2NEMO contributes to the development of the COPERNICUS Marine Environment Monitoring Service (CMEMS). It specifically aims at improving the coupling of the ocean model system to wave models. The target areas are the North Sea, the Baltic Sea and the Mediterranean Sea. The main objectives of the project are:
• Further development of the NEMO ocean model and the forcing which will explicitly include the effect of waves from wave models on the upper ocean dynamics;
• Providing software for additional parameters which have to be exchanged between waves and hydrodynamic models,
• Improved validation methods by retrieved wave information from satellite data and in situ platforms (buoys, moorings, HF radars, etc.);
• Demonstrating the interaction of waves and currents at small scales both in the ocean interior as well as near the shoreline.
Most of the CMEMS target fields - marine safety, marine resources, marine environment and forecasting – will directly benefit from the proposed R&D work proposed here. Thus, it could be expected that the project will make connections to CMEMS in order to support the future production of more consistent ocean-marine weather information including on surface waves, which is often requested by users.

About the ESM project

The ESM project started on 1 April 2017 partly funded by the Helmholtz Association over a period of three years. The project comprises eight Helmholtz Research Centers and aims to improve the representation of the components of the Earth system and their coupling, as well as to perform a series of selected numerical experiments to address Grand Challenges (Frontier Simulations). A long-term strategy for the development of an Earth System Modelling capacity is also an objective of the project.

Human societies are facing grand challenges, which are expected to become even more prominent during the next decades – with climate change, availability of food, clean water and geoenergy resources being just some examples. In order to address these grand challenges, the scientific community needs to develop tools that provide decision makers with the information required to effectively manage these issues.

Earth system modelling is such a tool, as it enables investigating problems in an integrated manner considering interactions between different Earth system compartments and across scales – from local to global scales, and from weather time scales to millennia and beyond.

The ultimate goal of the project is to develop, evaluate and apply a world-leading Earth system modelling infrastructure —leading into an Earth System Simulator— to provide solutions to grand challenges faced by the Earth and environmental sciences.
Scientific and technical activities—the Scientific-technical Core—lie at the heart of the project. These include Earth System Model Development (WP1), the establishment of Earth System Data Assimilation (WP2) capacity as well as the development of an Earth System Diagnosis (WP3) framework. It is this Scientific-technical core, which will be developed into the first version of the “Earth System Simulator” in PoF-IV. In order to push existing boundaries in numerical experimentation, Frontier Simulations will be carried out in WP4. These “community” simulations will contribute to solving some of the grand challenges faced by the Earth and environmental sciences. At the same time, these simulations serve as demonstrations of the capability of the Earth system model infrastructure. The scientifically focussed work will be flanked by a Strategic Development component (WP5) that will lead into a long-term Earth system modelling strategy as well as a concrete implementation plan for PoF-IV.

DWD Vertrag

Within the framework of further improvements of the community wave model WAM and the atmospheric model ICON, a detailed comparison between the roughness lengths obtained by WAM and ICON provides profound insight whether the use of the more realistic WAM roughness lengths over sea would be able to improve the operational weather forecast system of the German Met Service (DWD: Deutscher Wetterdienst). That presents a first step into the development of a future coupled system between ICON and WAM. Furthermore several new integrated wave parameters will be included in the official output list of the wave model WAM which are up to three different swell systems instead of a total swell only and the energy and momentum fluxes into the ocean that are required for coupling purposes with hydrodynamic models.
The contract is funded by the DWD.

JERICO-NEXT

The coastal area is the most productive and dynamic environment of the World Ocean with significant resources and services for mankind. JERICO-NEXT emphasizes that the complexity of the coastal ocean cannot be well understood if interconnection between physics, biogeochemistry and biology is not guaranteed. Such integration requires new technological developments allowing continuous monitoring of a larger set of parameters. In the continuity of JERICO(FP7), the objective of JERICO-NEXT consists in strengthening and enlarging a solid and transparent European network in providing operational services for the timely, continuous and sustainable delivery of high quality environmental data and information products related to marine environment in European coastal seas. Other JERICO-NEXT objectives include: Support to European coastal research communities, enable free and open access to data, enhance the readiness of new observing platform networks by increasing the performance of sensors, showcase of the adequacy of the so-developed observing technologies and strategies, propose a medium-term roadmap for coastal observatories through a permanent dialogue with stakeholders. Although JERICO-NEXT already includes industrial partners, it will be open to other research institutes, laboratories and private companies which could become associated partners to the project.

The HZG contribution to JERICO-NEXT is through its North Sea coastal observatory system COSYNA.
Furthermore, observation system assessments will be performed using numerical models. One particular focus is on HF radar systems.

WIPAFF (Analyse der Eigenschaften und Auswirkungen von Offshore Windpark-Fernfeldern)

Mehr als 500 Offshore-Windenergieanlagen gingen allein 2015 in Deutschland ans Netz. Wie solche Windparks sich untereinander beeinflussen und sich möglicherweise auf das lokale Klima auswirken, ließ sich bislang nur mit Modellen annähern. Der großflächige Ausbau macht es nun erstmals möglich, diese Effekte in der Realität zu untersuchen.

Das ist Gegenstand des BMWI geförderten Forschungsprojekts „WIPAFF", das vom Karlsruher Instituts für Technologie zusammen mit dem HZG, der Universität Tübingen, der Universität Braunschweig und dem Deutschen Windinstitut (DEWI) durchgeführt wird. Die Ergebnisse sollen dazu beitragen, den weiteren Ausbau der Windkraftnutzung in der Nordsee möglichst effizient und umweltverträglich zu gestalten.

Ziel der Forscherinnen und Forscher am Institut für Küstenforschung des HZG ist die Untersuchung des Windfeldes für den Bereich zwischen 10 und 100 Kilometern hinter großen Windparks mit Hilfe von Messdaten und numerischen Modellen. Die Dynamik in diesem Bereich ist äußerst komplex und wird durch verschiedene Faktoren in der Atmosphäre, aber auch Eigenschaften der Wasseroberfläche beeinflusst. Eine interessante Frage, die die HZG Wissenschaftler zusammen mit Kollegen des IMK-IFU untersuchen wollen ist die Rolle des Seegangs für die Rauigkeit der Wasseroberfläche. Diese Rauigkeit spielt eine wichtige Rollen für den Impulsfluss von der Atmosphäre in den Ozean, d.h. der Abbremsung der unteren Luftschichten die Wasseroberfläche. In den bisher für die Modellierung der atmosphärischen Bedingungen im Bereich von Offshore Windfarmen verwendeten Modellen ist dieser Effekt nur sehr grob nachgebildet. Das HZG betreibt hochaufgelöste Seegangsmodelle für die Deutsche Bucht, die Informationen über Wellenhöhe, Wellenlänge, und Wellenausbreitungsrichtung liefern und die für diese Untersuchung verwendete werden sollen. Ein weiterer wichtiger Teil der Arbeiten am HZG wird sich mit der Analyse von Satellitendaten beschäftigen. Die Radarsensoren der Satelliten TerraSAR-X und SENTINEL-1 liefern Informationen über die Rauigkeit der Wasseroberfläche, die mit der Windgeschwindigkeit in der wassernahen Luftschicht in Verbindung steht. Mit den Radarbildern dieser Satelliten können große Teile der Deutschen Bucht mit einer hohen räumlichen Auflösung abgebildet werden. In der Regel ist es sogar möglich, einzelne Windturbinen zu erkennen. Mit Hilfe dieser Daten sollen Abschattungseffekte durch Windfarmen für verschiedene Wettersituation untersucht werden. Hierbei sind insbesondere die Distanzen, über die Windabschattungen in Abhängigkeit verschiedener Wettersituationen beobachtet werden können, von Interesse.

ESKP

(Earth System Knowledge Platform) is a platform under development informing about risks and chances of global change in the environment. The scientifically validated and processed information comprising the topics water, ground, climate or natural disasters shall enable the society, policymakers and economy to make sound decisions on preventive future strategies. Besides 8 Helmholtz Centres further partners are engaged in the project. Funding is provided by the German Research Society (Deutsche Forchungsgemeinschaft) and the Ministry of Science and Culture of Lower Saxony.