Abstract:

According to the monitoring of geomagnetic field variations over the period 1958-1991 identified features solar-diurnal variations of Sq in the antarctic observatory AIA. Seasonal SqZ characteristics were obtained from the analysis of the shape SqZ variations. Additional morning-niqht maximum amplitude SqZ, amounting to 50% of the daily amplitude in June 3-4LT, discovered for the winter (04-09) type SqZ variations and was probably due to the current eastern swirl, like reqistered over southern Australia. Toqether with the neqative perturbation Sq near sunset (16-17) LT, as observed on a nearby observatory LIV, the morninq peak is not associated with solar Sq, no polar Sqp current systems. Autumn and spring was characterized by asymmetry (32-40) % of daily excess spring amplitudes observed in winter type SqZ variations due to lack of eguinoctial type of Sq variations on the AIA. Determined unegual annual chanqes in the value of long-term trends both diurnal amplitudes SqY> (0,3-0,5)SqZ variations within 0,25nT year after excluding the linear dependence of the amplitude of the index Sq F10.7. Spring and autumn marked asymmetry value of the trend by strengtheninq the positive trend in the first half of the year aqainst the backdrop of the trend value fluctuations; the reduction trend in winter and change the sign of the trend of amplitudes SqY in October. A positive trend of averaqe daily amplitudes of Sq variations, the value which amounted to 11% for the eastern SqY and more, 17-20% of the vertical magnetic field components SqZ to AIA for 33 years were obtained. The observed scatter of Sq amplitude trend values after minimized the impact of solar activity was due mainly by seasonal variations in the amplitude determining parameters Sq and by the trend calculation method.

Keywords: shape of Sq variations, autumn - spring asymmetry, trend of Sq daily amplitude