What's a false echo?

Dateline article| David Murphy|

As the name implies, a false echo is a returned image on a radar screen that looks like a heavy thunderstorm or rain, but is actually a ghost image of a storm many miles away. False echoes often appear under certain atmospheric conditions like an inversion (an unusual layering of temperatures above the ground) that can manipulate a radar's signal. Some false echoes appear in the early morning around sunrise, as a typical morning inversion of the atmosphere bends the radar's signal into the ground, causing a dramatic, heavy echo where the scan is contacting the surface. Others are caused by old return pulses from a distant object being misinterpreted by the radar's processor.

---David Murphy

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