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

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 (8.7 degreesN, 77.8 degreesE geographic, 0.35 degreesN 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. (C) 2001 Elsevier Science Ltd. All rights reserved.