Models, Data, and Methodology - On the Effect of Offshore Wind Farms on the Atmosphere and Ocean Dynamics - page 20

Fig. 3.2 Geographical location of the model area ( left ) and its arrangement as an idealized ocean
box ( right ). The blue square within the North Sea marks the model area with the wind farm alpha
ventus in the middle , whose position is given by a red point ( left ). The investigation area contains a
box with a horizontal dimension of 240 km 240 km and a maximal deepness of 60 m. Each grid
box is sized 3 km 3 km in the horizontal, which means a horizontal resolution of 2.5 0 1.5 0 in
HAMSOM, and 2 m in the vertical. Topography, respectively land mass, within the box is
neglected; the bottom is flat, and ocean boundaries are treated as open. The OWFs used are placed
in the middle of the box. The atmosphere box in METRAS has the same horizontal dimension and
resolution of 3 km 3 km but differs, in comparison with HAMSOM, in the vertical resolution
Topography in TOS-01 (Model Box)
In both cases, atmosphere modeling and ocean modeling, the topography and
bathymetry, respectively, are flat to elicit the sole effect of induced changes in
dynamics by OWFs.
Offshore Wind Farms in TOS-01 (Model Box)
For analysis, different OWFs were used, which all were implemented around the
center of the model area. The wind turbines are considered only in METRAS model
due to the wind turbine parameterization, which is documented in Sect. 3.1.2 .In
ocean simulations, the OWFs are only implemented via meteorological forcing
fields that were simulated in the METRAS model.
The size of the OWFs varies due to different experiments. One OWF, mostly
used for analysis, consists of 12 wind turbines with an arrangement based on the
German test wind park alpha ventus .
Additional tested OWFs consist of 48, 80, and 160 turbines arranged in four or
rather eight rows; see Fig. 3.3 . These different OWFs are used to evaluate changes
on the atmospheric wind field and ocean due to different wind park sizes. The
number of turbines is based on currently available and planned OWFs in the North
Sea (approved wind farm projects within the North Sea listed under BSH 2013 ).
Each wind turbine, implemented in METRAS, has a hub height of 80 m and a rotor
diameter of 80 m. The rotator disc directly affects the vertical heights, ranging from