Civil Engineering Reference
In-Depth Information
The OWF effect on salinity
gives a change in order of 0.2 psu, particularly
0.3 psu. At surface, the salinity concentration decreases for the wind direction
clockwise from east to west (Fig.
6.14
). The wind directions having a northern
component also result in a slight increase of 0.3 psu. In 12.5-m depth (Fig.
6.15
), the
increase and decrease of salinity concentration are mostly balanced as a result of the
vertical motion. In average over all wind direction cases, the increase of salinity
concentration counts 0.33 psu, which equates to a change of 0.95 %, and the salinity
decrease counts 0.31 psu, a change of 0.88 %. A maximal increase of salinity
concentration of 0.98 psu is registered in the wind case direction W, the maximal
decrease of
0.49 psu is found in the wind case direction N.
Summarizing
the analysis of the OWF effect on the German Bight, under
constant wind directions, gives an idea of possible dynamical and hydrographical
variations due to produced wind wake. Important here is a change in the surface
elevation in order of centimeters; the change in belts of vertical up- and
downwelling is in order of 3-5 m per day, giving the German Bight a
whirlpool
'
character. Hydrographic changes are significantly related to the temperature/salin-
ity in order of
'
0.2
C and
0.3 psu. But hydrographic variations can increase
based on atmospheric boundary layer resulting in a warming of more than 1
C,
respectively cooling.
6.2 Case Study II: OWF
s Impact Based on a Real
Meteorological Situation
'
Various theoretical assumptions were analyzed to estimate OWFs
effect on the
atmosphere and, especially, on the ocean. For a better estimation of the OWF effect
under daily wind variability, the simulations of scenario
B1-2030much
consider
realistic meteorological conditions. Therefore, a meteorological situation in June
2010 is chosen as a realistic example.
Simulations of June 2010 were done over the days 16-19 again for operating
wind turbines (OWFr) and for no wind turbines (REFr). The wind turbines only
operate at wind speeds between 2.5 and 17 m/s at hub height. The ocean runs are
based on North Sea simulations (TOS-02), described in Sect. 3.3.2. The result
presentation focuses on daily means calculated by a 10-min mean model output.
The mid of June 2010 denotes an interesting weather situation with a strong
cooling effect over Europe, with strong precipitation events, including snow in the
Alps. Synoptic inspection shows that Germany was in sphere of a long-wave trough
with an expansion from Scandinavia up to the Mediterranean Sea. The focus of the
activity was placed on Scandinavia, which was connected with a ground low
pressure over mid-Scandinavia. During the days from 16 to 19 June 2010, the
frontal system crossed Germany from NW to SE, which results, especially over the
Alps, in extensive rainfall. To easily integrate that meteorological situation over the
4 days, Fig.
6.17
shows 500 hPa geopotential for each day.
'
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