WICHITA, Kan. (KSNW) — You may have noticed activity showing up on radar before, then looked outside and saw nothing but sunshine. This is common, especially at a doppler radar site. This is known as anomalous propagation, or ground clutter.
Radar is an incredibly useful tool for both meteorologists and you at home. Ground clutter happens when the radar sends out a burst of energy and that energy travels until it hits something (rain, snow, ice, even birds), then returns to the radar site to be collected. This gives us the best idea of what type of precipitation is possible, where the precipitation is located and even how fast it is moving. According to the National Weather Service, doppler radars generally emit over 1,300 beams of energy per second to scan our skies.
Sometimes a beam of energy can hit things other than precipitation, especially right at the radar site. The radar beam is slanted at an angle. The closer you are to the radar, the lower the beam is scanning. This creates plenty of ground clutter. Moving particulates as small as dust can be picked up right around the radar site, giving a false return. We can even see insect hatches and bird migrations!
Those near the Dodge City doppler radar experience ground clutter daily. This comes in the form of wind farm interference. The rotating turbines are so tall, the radar beam hits the turbines and returns that signal to the radar thinking it is something large, like heavy precipitation. This obviously is not the case. If you look at radar near Dodge City, the wind farms look like stationary thunderstorms. That is the key — they are stationary. This is the best way to decipher between ground clutter and real precipitation. Generally, precipitation will be moving, even if it is slow. Ground clutter will not move and dance in the same spot.
Weather phenomena like temperature inversions can enhance the ground clutter even more in the morning hours.
-Meteorologist Warren Sears