Aerosols in the Mesopause Region: A Bipolar Perspective
Australian Antarctic Division
Over the past few years, co-located radar and lidar measurements have been made of ice aerosol layers in the summer mesospause region (80-95 km height) above Australia's Davis station in Antarctica. These measurements have enabled the first common-volume measurements in the Southern Hemisphere of Polar Mesosphere Summer Echoes (PMSE) and Polar Mesospheric Clouds (PMC). Davis is situated at 69ÂºS latitude and thus of similar polar latitude to Andenes. This has provided the opportunity to make comparisons of PMSE and PMC between the two hemispheres. We find some interesting differences; both phenomena are higher in altitude (by ~1 km), fainter and less common over Davis than for Andenes. Using global satellite temperature and water vapour measurement, we show that this relates to inter-hemispheric differences in the climate of the summer mesopause. Part of this difference is consistent with expected temperature differences caused by ellipticity of Earth's orbit, while differences in wave forcing in the two hemispheres likely provides an additional contribution.
An important current direction of our studies involves comparison with results from the MARA atmospheric radar operated by IRF at Wasa station in Antarctica. This work is providing unique details on Antarctic PMSE, including a new perspective on height variations of the mesopause and the influence of planetary waves on the polar atmosphere.
In this talk I will first provide an introduction to the work of the Australian Antarctic Division, and our atmospheric research programme. I will go on to highlight the mesopause region work undertaken at Davis and show how this links with current and planned research at Wasa and Andenes.