Analysis 03: Future Scenario—OWF Development Within German EEZ - On the Effect of Offshore Wind Farms on the Atmosphere and Ocean Dynamics - page 129

stratification over water keeps the OWF induced cooling (Linde et al. n.d. ). The
overall cooling, documented in Linde et al. ( n.d. ), is a result of a stronger impact
during the night than during the day.
However, here, conditions do not really change with time causing only a
warming and drying of lower layers.

6.1.2 Effect on the Ocean in the German EEZ Based on Case
Study I

This section provides dynamical and hydrographical changes of the ocean over the
German Bight simulated with HAMSOM for case study I (constant wind direction
over 1 day). Figure 6.6 shows the representative temperature stratification of the
North Sea along the latitude 54.62 through the model area after 24 h of simulation
of REFr based on conditions of June 2011. Also, an important point of that
representation is that stratification over simulation time of 1 day does not vary in
REFr. Hence, changes only occur due to the operating OWFs in OWFr. The
maximal SSTs are around 13.0 C in coastal areas, and at bottom temperature
reaches 7.63 C.
In the following, differences in fields between OWFr and REFr are presented for
each defined wind direction after 1 day of simulation for surface elevation, vertical
velocity component w , horizontal velocity components u and v , temperature, and
salinity. As shown in the results of the surface elevation, the velocity components
are based on runs with full meteorological forcing. The presentation of temperature
and salinity is distinguished into wind and pressure forcing only and full meteoro-
logical forcing. That is necessary because here the OWF effect on the temperature
indicates a warming, which is in opposition to the general OWF cooling over ocean
that is found in literature. As analyzed in Sect. 5.3.5 , the meteorological forcing
including temperature and humidity mainly affects the hydrographic conditions of
the ocean s upper layers, especially at the sea surface. The surface elevation and the

'

lon (deg)

4 567 8 910

3. 02 4.27 5.52 6.77 8.02 9.27 10. 5 2

15.00

00

05

13.75

10

12.50

15

20

11.25

25

10.00

30

35 8.75

40

time: 24h

7.50

45

min: 7.6319
max: 12.8988

OWF areas

6.25

55

W E

65

5.00

0 30 60 90 120 150 180 210 240 270 300 330 360 390 420 450 480 510

4 5678910

x (km)

Fig. 6.6 Left : Latitude 54.62 ( red line ) through model area with scenario B-2030much. Black
surrounded areas mark fields of offshore wind farms. Right : Reference temperature stratification
along latitude of 54.62 based on June 2011 and SW wind direction as an example. The gray
shaded area is land, respectively bathymetry. Horizontal and vertical gray lines mark the position
of areas, including wind turbines. Values are given in degree Celsius. SST for other wind
directions varies slightly in coastal regions