Polar mesosphere summer echoes at Wasa, Antarctica (73°S): First observations and comparison with 68°N

Abstract

Polar mesosphere summer echoes (PMSE) have been observed for the first time at Wasa, Antarctica (73°S, 13°W, 61° geomagnetic). A new 54.5 MHz radar, MARA, operated first in Kiruna (68°N) during late summer 2006 and then at Wasa between 18 January and 5 February 2007. Operation in Kiruna allowed accurate cross calibration with the permanent 52 MHz radar ESRAD. PMSE at 73°S are found to have very similar characteristics to PMSE at 68°N. When observations from the same part of the summer season are compared, volume reflectivities show very similar distributions over different intensities, over height and over local-time. PMSE at 68°N (65° geomagnetic) are stronger in the midnight sector, likely due to the different geomagnetic latitudes. Above 85 km altitude, weak PMSE have a higher occurrence rate at 73°S. The height of peak PMSE occurrence is ∼1 km higher at 73°S compared to 68°N. Copyright 2007 by the American Geophysical Union.