Observations of the quasi 2‐day wave from the High Resolution Doppler Imager on Uars

Abstract

A strong westward traveling oscillation, with a period of 2 days and zonal wave number 3, is observed in the mesospheric and lower thermospheric winds from the High Resolution Doppler Imager on the Upper Atmosphere Research Satellite. The important events happen in January, July, and September/October, of which the occurrence in January is the strongest with an amplitude over 60ms −1 . Detailed analyses for the periods of January 1992 and January 1993 reveal a cause‐and‐effect relationship in the wave developing process at 95km. The global structures of the wave amplitude and phase are also presented.