Civil Engineering Reference
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evaporation and precipitation, while evaporation is calculated from the turbulent
flux of water vapor.
In METRAS, the atmospheric boundary layer cools within the OWF due to the
advection of cooler air from higher atmosphere layers to layers below the turbine
rotation disc of METRAS wind turbine parameterization.
A comparison of the ocean
s temperature stratification built without (F01) and
with (F03) full meteorological forcing after 1 day of operating wind turbines is
given in Fig. 5.34 . That cooling can be finally pursued in upper ocean layers. Here,
the difference between the simulation with full meteorological forcing (F03) and
without (F01) along the W-E and S-N cross sections through the OWF shows that
the use of the full meteorological forcing ends in a cooling down to the thermocline
round
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1.30 C. That cooling results in a drop of the thermocline from 12 to 14-m
depths. Due to that, the differences between F03 and F01 in Fig. 5.34c show
positive values around 12 m. The nearly homogeneous upper layer of temperature
in F03 (Fig. 5.34b ) with a mean value of 12.5 C spreads from top to 14-m depth,
while in F01, the upper layer of an average of 14.0 C ends above the thermocline,
and in 12-m depth the temperature is 12 C. The warmer region within the OWF
above the thermocline in the case of F03 is a result of the velocity wake. The use of
F03 stamps mightiness of the upper temperature layer. That fact and the cooling
involve a shift of OWF effects extrema.
Figure 5.35 illustrates the velocity components u and w , temperature, and
salinity at three/two points within the OWF, 12 km southerly and 6 km northerly
to the OWF along the S-N cross section over depth. Especially in the downwelling
region, that switch is apparent. The minimum of velocity component w is placed at
the thermocline in 12-m depth for F01, and in the case of F03, minimum is located
at 14 m. The same behavior is given for temperature, Fig. 5.35c .
At position P 1, within the upwelling region, maximal vertical velocities are
placed at 11 m for F01 and at 13 m for F03, but the corresponding temperature
minima are both in 10 m due to the temperature exclusion of the same intensity at
this point. Simulations with F01 and F03 are correlated with 0.70 for temperature,
0.96 for w -component, 0.7-0.9 for u -component, and 0.57/0.80 for salinity. Differ-
ences at u -component occur at the wake flanks biased by 0.001 m/s, vertical
velocity component
is biased by 10 6 -10 7 m/s,
temperature has a bias of
0.13/0.19 C, and salinity has a bias of 0.008, especially in the upper layer. As
mentioned, changes of the ocean
s temperature are connected with the forcing air
temperature, and due to the humidity forcing, which influences the ocean
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s evap-
oration, the salinity concentration changes, although there is no precipitation.
Based on that statistics at reference positions the effect of run F03 on the
hydrodynamics is weak in comparison with the effect on the hydrographic condi-
tions, especially for the upper layers.
Analysis of values in the horizontal at different depths, pictured in Fig. 5.36 ,
underlines that statement. Figure 5.36 illustrates the condition of the ocean system
at investigation positions through the model area chosen by considering extrema.
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