Signatures of quasi-2-day planetary waves in the equatorial electrojet: results from simultaneous observations of mesospheric winds and geomagnetic eld variations at low latitudes

Abstract

Observations of mesospheric winds in the altitude region 84–98 km with the medium frequency (MF) radar located close to the magnetic equator at Tirunelveli ( geographic, 0.35°N magnetic dip), India, and the ground-based geomagnetic data from the low latitude Indian sector, are used to identify the signatures of the quasi-2-day (QTD) planetary waves in the equatorial electrojet (EEJ). It is found that there is a reasonable correlation between the occurrence times of the quasi-2-day oscillation in the EEJ strength and the mesospheric winds as revealed by the observations.