Study of sporadic-E clouds by backscatter radar

Abstract

It is shown that swept-frequency backscatter ionograms covering a range of azimuths can be used to study the dynamics of sporadic-E clouds. A simple technique based on analytic ray tracing can be used to simulate the observed narrow traces associated with Es patches. This enables the location and extent of the sporadic-E clouds to be determined. The motion of clouds can then be determined from a time sequence of records. In order to demonstrate the method, results are presented from an initial study of 5 days of backscatter ionograms from the Jindalee Stage B data base obtained during March-April 1990. Usually 2-3 clouds were observed each day, mainly during the evening and up to midnight. The clouds lasted from 1-4 h and extended between 30°-80° in azimuth and 150-800 km in range. The clouds were mostly stationary or drifted generally westward with velocities of up to 80 ms-1. Only one cloud was observed moving eastward.