Behaviour of the F2 region over the Argentine Antarctic sector

MOSERT, M., R.G. EZQUER, G. MANSILLA, J. ARAUJO, Y. MIGOYA ORUE

Praga Republica Checa

Workshop; IRI/Cost296 Workshop; 2007

The terrestrial ionosphere may be divided broadly into three regions that have rather different properties (Hunsucker and Hargreaves, 2003):   the equatorial zone, within 20° of the magnetic equator the high-latitude zone, poleward of about 60° geomagnetic the temperate zone in between   The high latitude zone may be sub-divided into the auroral zone (approximately 60°-70° magnetic) and the polar cap  (poleward of the auroral zone).   The ionospheric parameters, strongly dependent on the solar conditions and on the complex behaviour of the magnetosphere, are very interesting for studying the complex phenomena and high degree of space/time variability of the ionosphere occurring at the high latitude regions.  Moreover, the analysis of the ionospheric data contributes to give a real time evaluation of HF radiopropagation conditions “in situ” and to test the available ionospheric prediction methods.   Whereas the mid-latitude ionosphere is dominated by solar radiation and the chemistry of the upper atmosphere, modified by dynamic effects, the high-latitude ionosphere is, in addition, strongly affected by the nature of the geophysical environment and by various processes occurring within it. In particular, the form of the geomagnetic field connects the polar upper atmosphere to the magnetosphere. Thereby the polar ionosphere becomes accessible to particles that have been energized within the magnetosphere or have come from the Sun; these provide another source of ionization. It is also affected by the dynamics of the magnetosphere and is thus subjet to electric fields and currents generated by motions at high levels. At the highest latitudes the ionosphere is connected, via the field-lines, to the outer magnetosphere, giving it a ready response to variations in the flow of the solar wind.   The known features of the high latitude region have been derived mainly from observations in the northen hemisphere. However marked differences between the hemispheres have been observed (Mallis and Essex, 1993) In the Argentine Antarctic Sector there are two ionospheric stations:   SanMartín (68.1°S; 293.0°E geographic; 53° S magnetic)   Belgrano (77.9°S; 321.4°E geographic, 67.5° magnetic).   Vertical ionospheric soundings have been done for more than 4 decades in the Antarctic region. However only some few studies can be found in the literature using the Antarctic ionospheric data base.   From 1994 the to ionospheric stations in Antarctic region are equipped by a KEL AEROSPACE  IPS 42 ionosonde  and a digitizing  system  for the vertical incident soundings.