Composite shadowing describes which of the following on the radar display?

• A. It is the sum of all shadowing effects that cancel out on the radar.
• B. It is the radar phenomenon where only vertical shadowing occurs.
• C. It is the radar phenomenon where only horizontal shadowing occurs.
• D. It is the combination of horizontal and vertical shadowing observed on the RADAR display as changing responses to the land.

Answer: (D)

Shadowing on a radar display comes from terrain blocking or attenuating the radar beam. There are two ways this can happen: horizontal shadowing, where terrain blocks the beam along the ground plane and creates a shadow behind features in the horizontal direction; and vertical shadowing, where terrain rises into the beam and eliminates returns from targets behind it in the vertical plane. When both effects are present, they combine into a single, complex pattern—the composite shadowing—so the radar display shows a mix of shadowed areas that change as the land geometry and beam angle change. That’s why the answer describes composite shadowing as the combination of horizontal and vertical shadowing observed on the display as responses to the terrain change.