Inhomogeneous structure of the high-latitude ionosphere as observed at Norilsk

In March and August/September 1995, February 1996, and in March-April 1998, observations of the inhomogeneous structure of the high-latitude ionosphere were carried out at Norilsk (geomagnetic latitude and longitude are 64.2 N and 160.4 E, and L=5.2). Small-scale irregularities (with the lifetime of several seconds,and the spatial scale less than 5-7 km), and medium-size wave irregularities(with the period of 10-50 min, and the horizontal size of tens and hundreds of kilometres) of the ionospheric F layer were investigated under different geophysical conditions. A total of 300 hours of observations was recorded, including 250 reflections from the F2 layer, and the other reflections from the sporadic E layer. The diurnal variations of inhomogeneous structure parameters in March and April is obtained. Dependence of some ionospheric irregularity parameters on geomagnetic activity is presented.