Parameters of small- and medium-scale irregularities in the high-latitude ionosphere as inferred from the Noril'sk observations

From 1995 to 1996, observations were made in Noril'sk in order to determine the dynamic parameters of variously scaled irregularities in the high-lati tude ionosphere. The short-baseline space-diversity reception technique imp lemented at the ionospheric complex of the Noril'sk Complex MagnetoIonosphe ric Station allows for the parameters of both small-scale irregularities an d medium-scale wave irregularities to be simultaneously determined using D1 and phase-difference methods, respectively. The results of about 20 h of F 2-layer observations under quiet geomagnetic conditions, 20 h of observatio ns under disturbed conditions, and about 15 h of sporadic E-s-layer observa tions are reduced. The irregularities of different scale lengths are found to move in different directions and at different speeds. Small-scale M-laye r irregularities move mainly east- and westward. F2-layer irregularities ha ve velocities of about similar to 100 m/s, which can be as high as similar to 200-500 m/s under disturbed conditions. Small-scale irregularities of th e sporadic E-layer move mainly northward. It is confirmed that some irregul arities in the sporadic E-layer move at high velocities (up to 1000 m/s). M edium-scale wave irregularities in the period range of 10-30 min are found to move mainly southward at velocities of 20-40 m/s.