11 / 20
The airborne weather radar..
  • A
    uses circular polarisation in order to reduce echoes of heavy showers.
  • B
    may receive no reflections from a thunderstorm in an area behind a heavy rain shower.
  • C
    has a second transmitter working on a lower frequency in order to penetrate rain showers.
  • D
    has the possibility to detect clear air turbulence behind a thunder storm by measuring phase differences caused by the Doppler effect.

Refer to figure.


The weather radar display depends on signal returns: the more intense the precipitation, the less distance the radar can see through. Therefore when the radar echo is unable to make the two way trip through heavy precipitation, a "shadowing" effect occurs.

The stronger the rainstorm, the more radar energy will be scattered by Weather Attenuation. In simple words, Radar attenuation or shadowing is simply the absorption or reflection of radar signals as the radar pulse penetrates an area of precipitation, preventing that radar from detecting any additional cells that lie behind the first storm.

  • The AWR is blind to whatever conditions may be lurking behind the thunderstorm. In the area where the shadowing occurs, conditions are unknown.

Your Notes (not visible to others)

This question has appeared on the real examination, you can find the related countries below.