Abstract. The World Meteorological Organization (WMO) has repeatedly expressed concern over the increasing number of impact cases of wind turbine farms on weather radars. Current signal processing techniques to mitigate wind turbine clutter (WTC) are scarce, so the most practical approach to this issue is the assessment of the potential interference from a wind farm before it is installed. To do so, and in order to obtain a WTC reflectivity model, it is crucial to estimate the radar cross section (RCS) of the wind turbines to be built, which represents the power percentage of the radar signal that is backscattered to the radar receiver.For the proposed model, a representative scenario has been chosen in which both the weather radar and the wind farm are placed on clear areas; i.e., wind turbines are supposed to be illuminated only by the lowest elevation angles of the radar beam.This paper first characterizes the RCS of wind turbines in the weather radar frequency bands by means of computer simulations based on the physical optics theory and then proposes a simplified model to estimate wind turbine RCS values. This model is of great help in the evaluation of the potential impact of a certain wind farm on the weather radar operation.

The potential impact that offshore wind farms may cause on nearby marine radars should be considered before the wind farm is installed. Strong radar echoes from the turbines may degrade radars' detection capability in the area around the wind farm. Although conventional computational methods provide accurate results of scattering by wind turbines, they are not directly implementable in software tools that can be used to conduct the impact studies. This paper proposes a simple model to assess the clutter that wind turbines may generate on marine radars. This method can be easily implemented in the system modeling software tools for the impact analysis of a wind farm in a real scenario.

This paper describes the results of two extensive measurement campaigns for evaluating the potential impact of scattered signals from wind turbines on terrestrial DTV reception quality in the UHF band. A detailed description of the different propagation channels encountered is provided. Furthermore, empirical threshold carrier-to-noise requirements for Quasi Error Free reception in the DVB-T system in the area of influence of a wind farm are presented, and the situations where a significant degradation can be found are identified and characterized.

The prediction of the potential impact of a wind farm on the existing radiocommunication services before its installation allows the planning of alternative solutions to ensure the coexistence of wind energy and telecommunication facilities. Although some guidelines for safeguarding radiocommunication services have been recently published, the precise impact on a specific service can only be determined on a case-by-case basis, due to the multiple factors that must be considered in the analysis. This paper presents a software tool that allows the accurate analysis of the degradation of the different radiocommunication systems. The calculations are based on the configuration of a specific wind farm and the different transmitters and receivers over a terrain database containing high resolution altimetry data. For each type of service, suitable calculation algorithms and interference criteria are applied. Graphic and numerical results of the analysis are presented on a map, which allows an on-thespot evaluation of the degradation mechanisms for each wind turbine. Index Terms -Propagation and Coverage, DTV and broadband multimedia systems, Channel modeling and simulation

This study proposes a field data-based methodology to characterize the scattered signals from wind turbines. The method is based on the scattering pattern of the wind turbine, empirically obtained from the estimation of the Channel Impulse Response, which allows the accurate estimation of the amplitude and the time variation of the scattered signals. The analysis of the Channel Impulse Response at different situations, such as the rotation speed, the orientation of the turbine or the elevation and azimuth angles of the receiver location, will allow the proper characterization of this phenomenon, and therefore, the development of an empirical model for the estimation of the potential interference of wind farms.