Geomagnetic Quiet Time (Sq) Variations at High Latitudes

The availability of geomagnetic data from two Antarctic Geophysical Observatories (AGOs P5 and P6; magnetic latitudes 87degrees S and 85degrees S) in the deep southern hemisphere polar cap allows for the first time the study of the geomagnetic "quiet time" variations (Sq) at the highest latitudes possible. We present analyses of the Sq variations at these two AGO sites for data obtained in 1997, and compare them with model predictions. We find strong evidence that the Sq variations near 90 degrees S geomagnetic latitude are considerably larger (factor or two or more) than would be expected from the model, independent of season. An examination of the variations in the vertical components and their comparisons to the model indicates that there appear to be differences in the Earth's deep mantle conductivity structure under the Antarctic ice cap at the two locations.