Gravity waves have a significant dynamic effect in the mesosphere. In particular, they drive the mesospheric circulation and are the reason that the summer polar mesosphere is cooler than the winter polar mesosphere. This thesis examines whether the effects of gravity waves are largely determined by filtering effects which allow only gravity waves with certain properties to propagate into the atmosphere. The filtering of gravity waves above Scott Base, Antarctica is examined using a radiosonde derived gravity wave source function, an MF-radar derived mesospheric gravity wave climatology, and a model derived filtering function. Least squares fitting of the source function and filtering function to the observed mesospheric gravity wave climatology allows us to determine which gravity wave phase velocities and propagation direction are likely to be present in the mesosphere and the relative importance of filtering and sources in this region. It is concluded the blocking of eastward gravity waves is important in winter and westward waves in summer.
| Identifer | oai:union.ndltd.org:ADTP/274228 |
| Date | January 2008 |
| Creators | Geldenhuis, Andre |
| Publisher | University of Canterbury. Physics and Astronomy |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Copyright Andre Geldenhuis, http://library.canterbury.ac.nz/thesis/etheses_copyright.shtml |
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