Geoscience Reference
In-Depth Information
Range Potential impact
Guideline
0-5 km The wind turbine may completely or
partially block the radar and can result
in significant loss of data that can not be
recovered.
Definite Impact Zone: Wind turbines
should not be installed in this zone.
5-20 km Multiple reflection and multi-path
scattering can create false echoes and
multiple elevations. Doppler velocity
measurements may be compromised
by rotating blades.
Moderate Impact Zone: Terrain
effects will be a factor. Analysis
and consultation is recommended.
Re-orientation or re-siting of individual
turbines may reduce or mitigate the
impact.
20-45 km Generally visible on the lowest
elevation scan; ground-like echoes will
be observed in reflectivity; Doppler
velocities may be compromised by
rotating blades.
Low Impact Zone: Notification is
recommended.
>
45 km Generally not observed in the data
but can be visible due to propagation
conditions.
Intermittent Impact Zone: Notification
is recommended.
Table 1. WMO guidance statement on weather radar/wind turbine siting. (FromWMO
(2010))
Range Radar Statement
0-5 km C-band No wind turbine should be deployed within this range
5-20 km C-band Wind farm projects should be submitted for an impact study
0-10 km S-band No wind turbine should be deployed within this range
10-30 km S-band Wind farm projects should be submitted for an impact study
Table 2. Statement of the OPERA group on the cohabitation between weather radars and
wind turbines. (From OPERA (2010))
clutter originates from targets having radial velocities larger than the clutter filter limits.
Dynamic clutter can therefore not be suppressed by conventional clutter filters.
Operating wind turbines generate both static and dynamic clutter. Since the static clutter from
the wind turbines is suppressed by clutter filters the dynamic wind turbine clutter, mainly
originating from the rotating blades, has the largest impact on weather radar measurements.
Dynamic wind turbine clutter (in the following referred to as wind turbine clutter) is often
difficult to separate from precipitation echoes and may therefore incorrectly be interpreted by
the weather radar as precipitation.
In addition, wind turbine clutter is highly variable in time since the amplitude of the scattered
signal depends sensitively on the wind turbine's yaw- and tilt angle.
3.1.1 Observations
Observations of wind turbine clutter have been presented in numerous works (e.g. Agence
National des Fréquences (2005); Burgess et al. (2008); Gallardo et al. (2008); Haase et al. (2010);
Isom et al. (2009); Toth et al. (2011); Tristant (2006a); Vogt et al. (2011; 2007a)). The strength
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