Weather Studies Radar Loop
Weather radar complememts satellite surveillance of the atmosphere by locating and tracking the movement of areas of precipitation and monitoring the circulation within small-scaleweather systems such as thunderstorms.
However, not all radar echoes are caused by meteorological phenomena. Special atmospheric conditions give rise to ground clutter mistaken for precipitation. For example, a strong temperature inversion may cause the outgoing radar signal to bend downward so it strikes the ground. Such ground clutter differs from precipitation echoes because it is stationary, stronger, and grainier in appearance. Often, these anomalous propagation patterns appear just prior to sunrise when a strong low-level temperature inversion is present.
Sometimes a radar screen shows a broad area of echoes, but weather stations located in the same area report no precipitation. In this case, the radar is detecting echoes from virga, rain and/or snow that vaporizes completely in the relatively dry air beneath cloud base.