  In the paper we have presented a technique of determining the scattering
irregularities (that cause coherent echo) layer parameters using the Irkutsk IS
radar data. It is shown that our technique has necessary accuracy (for height
and thickness - about 2.5 km, for aspect sensitivity - 5dB/degree). Processing
of the experiments 25-26.12.1998 and 15-16.07.2000 has shown a good agreement
of data calculated with the data obtained by other investigators: an average
layer height is 110-120km, average layer thickness 5km, average aspect
sensitivity - 15dB/degree. The investigation of the experiments with high
temporal resolution allowed us to observe temporal variations of the
irregularities layer parameters. The average thickness and height of the layer
does not contradict the data obtained by other investigators. The investigation
of the experiments with high temporal resolution allowed to detect time
variations of the layer parameters. The temporal variations of the aspect
sensitivity are observed by us for the first time and requires additional
investigations.
