Characteristics of the wind, temperature and PMSE field above Davis, Antarctica

Abstract

Polar Mesosphere Summer Echoes (PMSE) were detected above the high-latitude station Davis, Antarctica (68.6°S) using a 55 MHz atmospheric radar during the 2003–2004 austral summer. In this paper, we examine the characteristics of southern hemisphere PMSE events observed during the interval 19 November to 16 February 2004. Coincident satellite-SABER temperature measurements and ground-VHF radar backscatter observations revealed that PMSE existed for mesosphere temperatures in the range 124.4–134.7 K. An examination of the horizontal wind field using collocated VHF and MF radar measurements showed that PMSE also occurred during conditions of westward zonal winds and equatorward meridional winds. A remarkable correlation was evident between the onset (end) of the austral summer PMSE season and equatorward (poleward) flowing meridional mesospheric winds observed for the 19 November 2003 (16 February 2004), respectively. We present evidence of a semidiurnal influence of the meridional and zonal tides on the occurrence, intensity, and altitude of PMSE events. The effects of tidal, gravity and planetary waves on PMSE events are also considered.