The Antarctic Investigations of Upper Atmospheric Disturbances over the South Pole Station

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This proposal is for renewal of long-term aeronomical investigations of solar-terrestrial disturbances in the near-Earth space environment over the South Pole Station (SPS). Such disturbances modulate the composition, thermodynamics and dynamics of the middle atmosphere and thermosphere over SPS in Antarctica. It is proposed to continue operating the electro-optical, remote-sensing instruments at SPS to investigate: (1) source(s) and propagation of Antarctic F-region patches and their relation to the polar cap drizzles and the F-region dynamics; (2) changes in the Antarctic E-region O/N2 ratio in the center of the night-sector of the austral auroral oval compared to those in the sun-aligned auroral arcs in the polar cap region; and the heating and dynamics associated with these polar E-region compositional changes; (3) Antarctic middle atmosphere disturbances generated by Stratospheric Warming Events (SWE); and energetics of the coupling among the mesosphere and lower thermosphere (MLT) regions with the stratosphere through enhanced gravity waves in SWE; (4) Antarctic thermospheric response to Solar Magnetic Cloud/Coronal Mass Ejection (SMC/CME) events; and related changes in O2 atmospheric infrared band emissions above 150 km height; and (5) effects of the Joule heating on the thermodynamics of the Antarctic F-region; changes in kinetic temperature of the Antarctic F-region during Joule heating. Data for studies of all these five aeronomic processes will come from two sets of remote-sensing instruments: (1) auroral emissions brightness measurements from the sun-synchronous Meridian Scanning Photon Counting Multichannel photometer; and (2) airglow and auroral emission spectra recorded continuously during austral winter the high-resolution Infrared Michelson Interferometer and Visible/Near-Infrared CCD spectrographs. From about March through September of each year, such polar studies are only feasible at SPS since the Arctic stations are continuously sunlit. Changes in airglow temperature, from different MLT heights, permit studies of the dynamical effects of planetary, tidal and gravity waves propagating in the MLT regions as well as non-linear interactions among these waves. Like-wise, coupling of different atmospheric regions over SPS, through enhanced gravity wave activities during SWE that lead to a precursor as mesospheric cooling, can be investigated through the observed changes in MLT kinetic air temperature and density.