Statistical and Planned Studies of the Magnetospheric Open-Closed Boundary (OCB) using ULF Wave Observations from Antarctic Ground Magnetometers Combined with Conjugate Northern Hemisphere Stations

We present a statistical study using ground magnetometer data from the Antarctic Automated Geophysical Observatories (AGOs), McMurdo Station (MCM), and South Pole Station (SPA), to characterize open-closed boundary (OCB) behavior during geomagnetically quiet times. Knowledge of the location and dynamics of the magnetic field line OCB provides insight to space physics processes such as substorms, particle precipitation events, and magnetospheric configuration. Prior studies have shown that determination of the OCB location can be made by examining the ULF wave power in data from a latitudinal chain of ground-based magnetometers extending from the auroral zone into the deep polar cap. In this statistical study, AGOs 1, 2, 3, and 5, along with McMurdo and South Pole Station were studied. The seasons chosen were centered around the four cardinal dates: March 20th, June 21st, September 22nd, and December 21st. For each season, 60 days were selected centered around the cardinal date; any days with a planetary Ap greater than 30 were discarded. Using the H- component fluxgate data from each station, an average daily residual power spectra were calculated. The resultant spectrograms show signatures of whether a particular station is located in an open or closed magnetic region. We will present current Southern Hemisphere results, as well as planned studies of combining the Southern Hemisphere magnetometer data with observations from magnetically conjugate locations in the Northern Hemisphere.