Non-instrumental errors in ion velocities derived from Chatanika radar measurements during periods of changing ion velocities

Abstract

F-region ion velocities are obtained in one method with the Chatanika radar by successively sounding at three azimuths. Such measurements typically extend over thirty minutes, so that substantial non-instrumental error can occur when reconstituting a changing ion velocity from the three measurements. Three smoothly changing ion velocity models (similar to the ion velocity observed at Chatanika in the afternoon and evening) are examined and the errors due to the velocity change calculated. Even when only one component is varied, all three orthogonal components show substantial error. Three-point running-averaging is found to eliminate these errors for practical purposes; in the case for which the ion velocity varies linearly, the actual ion velocity is exactly recovered by this method.