Informing broadcasters and the viewing public about wind fams in weather radar products

The installation of wind “farms” to generate electricity and diversify our Nation's energy sources has grown dramatically in recent years and is expected to continue to grow. Wind farms can have over 100 towers with turbine blade tip heights exceeding 500 feet above ground level. Wind farms can be readily seen in the Doppler weather radar products of local broadcast station and federal government weather radars. The rotating blades of wind turbines reflect radar energy with a Doppler shift, which defeats the clutter filter algorithms. Unfortunately this wind turbine clutter (WTC) is can appear very similar to real weather. There are currently no known signal processing techniques that can differentiate the two types of returns.

Wind turbine clutter (WTC) can impact radar data quality, the performance of radar algorithms, and the end-users' ability to recognize significant weather events. Since 2006, the Weather Surveillance Radar-1988, Doppler (WSR-88D) Radar Operations Center (ROC) on behalf of the Next Generation Weather Radar (NEXRAD Program) has analyzed over 800 wind farm proposals on a case-by-case basis for potential interference with the nation-wide network of WSR-88D radars. Our analysis process, based in part on field experience, has matured and changed. The major change has been to estimate WTC impacts on WSR-88D data and forecast/severe weather warning performance separately. While WTC from nearly all wind turbines does not significantly impact weather forecast office operations, the appearance of WTC on radar products has led to misinterpretations by users such as the public, broadcasters, media, and emergency managers.

This paper and presentation will discuss the updated ROC WTC analysis procedures; outline recent efforts to mitigate WTC impacts; and provide an educational forum for broadcasters on how to identify WTC, explain its appearance on radar products shown during broadcasts, and be better able to explain impacts, if any, due to the appearance of WTC.