The 2021 Antarctic Total Eclipse: Ground Magnetometer and GNSS Wave
Observations from the 40 Degree Magnetic Meridian
Abstract
On December 04, 2021, a total solar eclipse occurred over west
Antarctica. Nearly an hour beforehand, a geomagnetic substorm onset was
observed in the northern hemisphere. Eclipses are suggested to influence
magnetosphere-ionosphere (MI) coupling dynamics by altering the
conductivity structure of the ionosphere by reducing photoionization.
This sudden and dramatic change in conductivity is not only likely to
alter global MI coupling, but it may also introduce a variety of
localized instabilities that appear in both hemispheres. Global
navigation satellite system (GNSS) based observations of the total
electron content (TEC) in the southern high latitude ionosphere during
the December 2021 eclipse show signs of wave activity coincident with
the eclipse peak totality. Ground magnetic observations in the same
region show similar activity, and our analysis suggest that these
observations are due to an “eclipse effect” rather than the prior
substorm. We present the first multi-point interhemispheric study of a
total south polar eclipse with local TEC observational context in
support of this conclusion.