  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.
