High‐resolution radar measurements of turbulent structure in the equatorial electrojet

Abstract

Observations of the equatorial electrojet were made with unprecedented altitude resolution at the Jicamarca Radio Observatory in January 1990. We obtained high‐quality Doppler spectra with 250‐m and sometimes better altitude resolution at heights from 95 to 120 km during the daytime and early evening with the large 50‐MHz radar. This resolution and coverage revealed a richness of dynamics and structure not previously appreciated, a structure that is sometimes reminiscent of VHF radar maps of equatorial spread F, albeit at smaller primary scale sizes. Individual scattering centers sometimes appear to drift in large swirls over many kilometers in altitude, maintaining their identity for times occasionally as long as a minute or two. On the other hand, we also see rapid variations with altitude (a kilometer or less) and time (a few seconds or less) in the Doppler spectra and signal power.