Gravity wave activities in the MLT observed by a meteor radar at King Sejong Station (62˚S, 57˚W), Antarctica

Abstract

We have analyzed horizontal wind data from a meteor radar at King Sejong Station, Antarctica to measure wind variances near the mesopause region. The horizontal wind variance within short time scales (up to 3 h), which was determined from individual meteor echoes, can be used to estimate gravity wave activity. As a measure for the gravity wave activity, we utilize wind variance derived by the least square method after subtraction of large scale variances due to both tidal variation and wind shear at each height interval. We present vertical profiles of monthly mean wind variances to characterize gravity wave activities over seasons. Gravity wave activities show seasonal behaviors with a semi-annual variation and height dependences. The gravity wave activity in the Antarctic region is believed to have a deep connection with zonal winds and the Antarctic vortex in lower atmosphere. By comparing our results with those from the Rothera station, we will discuss the relation of gravity wave activities between the mesosphere and lower atmosphere.