Trends in the geomagnetic SQ Field linked to foE long-term variations

ANA G. ELIAS; MARTA ZOSSI DE ARTIGAS

Saint Petersburg

Workshop; 5th Workshop on Long-Term Changes and Trends in the Atmosphere; 2008

IAGA - ICMA - CAWSES, Antarctic Research Institute (AARI)

Long-term changes in ionospheric parameters of time-scale longer than the 11-year solar activity cycle were analyzed by many authors in order to detect in the ionosphere an effect of the increasing greenhouse gases concentration. Theoretically, an increase in foE should be expected, among other changes, which in turn may imply increasing trends in conductivity at the corresponding height. The geomagnetic Sq field variations may also present trends since they are a manifestation of ionospheric current systems which flow in the E-region. The Sq variations of the horizontal component of the geomagnetic field, H, were assessed for several stations using hourly mean data records. The Sq daily-range of H was estimated using the average over the five quietest days for each month. The pattern of Sq trends obtained do not completely agree with the results which should be expected from foE long-term changes. The role of neutral winds and of the Earth?s magnetic field may be factors which should be added to foE trends in order to explain the Sq trend pattern.