Polar mesosphere summer echoes over Antarctica

Polar mesosphere summer echoes (PMSE) are strong signal power enhancements at very high radar frequencies that occur between about 80 and 95 kilometers [50 and 60 miles] in altitude (the mesosphere) near the poles during summer.

These phenomena are thought to provide information on mesospheric temperatures, a parameter which may shed light on whether the polar atmospheres between the northern and southern hemisphere are different. Most studies have focused on PMSE in the northern hemisphere. Morris et al. collected the first complete season of southern hemisphere PMSE data above Davis, Antarctica, using a 55-megahertz atmospheric radar during the 2004-2005 southern hemisphere summer. They supplemented their findings with Aura satellite temperature measurements and ground-based partial reflection observations to investigate the thermal and dynamical state of the polar mesosphere during conditions of PMSE occurrence. The authors found that peak occurrence of PMSEs corresponded with temperature lows. Further, the PMSEs are linked with the typical summer equatorward flow of mesospheric winds, but were perturbed when this wind flowed poleward.-American Geophysical Union