Latitutinal TEC Profiles over Argentina based on NNSS Differential Doppler Measurements During the Period 1994-1996

Kurzfassung

Differential Doppler measurements at the NNSS 150/400 MHz radio beacons were used to derive latitudinal profiles of TEC over Argentina. The measurements have been carried out in the frame of the German/Argentinean TECUA project. During this project NNSS receivers were installed in Argentina along a meridional chain at different places such as Tucuman, Mendoza, Trelew, and Ushuaia. The selected observation sites are suited to monitor the total ionization of the ionosphere over South America in the latitude range 15°--65° S. Calibrated TEC profiles were obtained by applying the two-station-calibration technique. To derive the mean diurnal and latitudinal variation of the ionosphere over Argentina, the observations are monthly averaged over the whole observation period. The observations near 60 W longitude indicate the position of the southward crest region at about 20--30° S. The observations are discussed and compared with corresponding TEC data computed from the IRI95 model.