EGU2020-12932
https://doi.org/10.5194/egusphere-egu2020-12932
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Wind wake effects of large offshore wind farms, an underrated impact on the marine ecosystem?

Corinna Schrum1,2, Naveed Akhtar1, Nils Christiansen1, Jeff Carpenter1, Ute Daewel1, Bughsin Djath1, Martin Hieronymi1, Burkhardt Rockel1, Johannes Schulz-Stellenfleth1, Larissa Schultze1, and Emil Stanev1
Corinna Schrum et al.
  • 1Helmholtz-Zentrum Geesthacht, Geesthacht, Germany (corinna.schrum@hzg.de)
  • 2Universität Hamburg, Hamburg, Germany

The North Sea is a world-wide hot-spot in offshore wind energy production and installed capacity is rapidly increasing. Current and potential future developments raise concerns about the implications for the environment and ecosystem. Offshore wind farms change the physical environment across scales in various ways, which have the potential to modify biogeochemical fluxes and ecosystem structure. The foundations of wind farms cause oceanic wakes and sediment fluxes into the water column. Oceanic wakes have spatial scales of about O(1km) and structure local ecosystems within and in the vicinity of wind farms. Spatially larger effects can be expected from wind deficits and atmospheric boundary layer turbulence arising from wind farms. Wind disturbances extend often over muliple tenths of kilometer and are detectable as large scale wind wakes. Moreover, boundary layer disturbances have the potential to change the local weather conditions and foster e.g. local cloud development. The atmospheric changes in turn changes ocean circulation and turbulence on the same large spatial scales and modulate ocean nutrient fluxes. The latter directly influences biological productivity and food web structure. These cascading effects from atmosphere to ocean hydrodynamics, biogeochemistry and foodwebs are likely underrated while assessing potential and risks of offshore wind.

We present latest evidence for local to regional environmental impacts, with a focus on wind wakes and discuss results from observations, remote sensing and modelling.  Using a suite of coupled atmosphere, ocean hydrodynamic and biogeochemistry models, we quantify the impact of large-scale offshore wind farms in the North Sea. The local and regional meteorological effects are studied using the regional climate model COSMO-CLM and the coupled ocean hydrodynamics-ecosystem model ECOSMO is used to study the consequent effects on ocean hydrodynamics and ocean productivity. Both models operate at a horizontal resolution of 2km.

How to cite: Schrum, C., Akhtar, N., Christiansen, N., Carpenter, J., Daewel, U., Djath, B., Hieronymi, M., Rockel, B., Schulz-Stellenfleth, J., Schultze, L., and Stanev, E.: Wind wake effects of large offshore wind farms, an underrated impact on the marine ecosystem?, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12932, https://doi.org/10.5194/egusphere-egu2020-12932, 2020

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