TID Parameters over the Antarctic Peninsula as Derived from TEC Measurements.

Abstract:

Results of TID analysis from multi-site TEC observations over the
Antarctic Peninsula for the period from 2009 to 2012 are presented.
Diurnal dependences of the occurrence frequency, and motion velocity
and direction probability density distributions are determined for
middle-scale traveling ionospheric disturbances (MSTIDs). TID
parameters are calculated using dynamic approach to the problem of
ionospheric disturbance diagnostics which has been extended to allow
for an arbitrary waveform of TEC perturbations. We have also developed
a dedicated algorithm to determine the presence of TID disturbances in
the TEC records which is based on the correlation analysis.
Statistical treatment of the obtained results shows that during
daytime the TIDs propagate predominantly in the northern and
northeastern directions. In the evening and nocturnal hours the
northwestern direction is prevailing, with the characteristic TID
velocities range from 10 to 250 m/s. The most probable TID velocities
are tens of meters per second, while the mean values are equal to
about 100 - 130 m/s. During the daytime the velocities of the
ionospheric disturbances are even higher. The work also presents
variations of the TID parameters with seasons and geomagnetic
conditions and the role of the solar terminator as a possible source
of the disturbances is discussed.