VHF radar measurements of the aspect sensitivity of the summer polar mesopause echoes over Andenes (69°N,16°E), Norway

Abstract

The mobile SOUSY VHF (53.5 MHz) radar, located near Andenes on the island of Andoya in Northern Norway, has been used to measure the aspect sensitivity of the very strong radar returns obtained from near the summer polar mesopause. This so‐called Polar Mesopause Summer Echo (PMSE) exhibits substantial aspect sensitivity, with angular polar diagrams of the backscatter of 2‐10° half‐width for a two day average. During one three hour period, in which the power received in the antenna vertical beam was particularly intense, the grating lobes of the antenna polar diagram were utilized as additional beams, and the power returned at angles of 35 and 38° off‐zenith was obtained. These measurements provide an estimate of the ratio of the specular to the turbulent contributions to the backscatter.