Why can the NEXRAD be reprogrammed to filter out returns from wind turbines?
REPLY: The NEXRADs clutter filter scheme only removes clutter that is stationary, such as buildings, trees, terrain. Unfortunately, both precipitation and wind turbine blades are moving, and the filter is not applied to them. Trying to filter out moving blades will inevitable alter how the radar sees real precipitation. Heres why. A single radar volume sample (gate) at 30 miles from the radar is approximately a square kilometer. Thus, for a typical wind farm, the radar may receive reflected energy from several turbines within that gate, each with multiple rotating blades. These numerous rotating blades appear similar to precipitation, which is also made up of numerous distributed moving targets. Yes, there are fewer blades than raindrops within a sample volume, but the blades make up for their smaller numbers by reflecting significantly more energy back to the radar. However, the radar has no way to determine the number of targets it is sampling within a particular gate. Also, the refl
