Meaning of riometer in English:

riometer

Pronunciation /riːˈɒmɪtə/

noun

Meteorology
  • An instrument for measuring the absorption of cosmic radio waves by the ionosphere.

    The riometer operates by comparing the measured radio noise with a long-term average value; the difference corresponds to the amount of ionospheric absorption.

Origin

1950s; earliest use found in Geophysics & IGY. From the initial letters of relative ionospheric opacity + -meter.