The effect of stratospheric warmings on the ionospheric D and F regions during 1985-1987

The behavior of the D and F regions of the atmosphere over south-eastern Europe during two different winter periods is studied. The first is the 1985-1986 winter belonging to the 'westerly category' with well-developed H2 wave activity in the stratosphere. The second is the 1986-1987 winter belonging to the 'easterly category' with well-developed H1 wave activity. In both winter periods, the major stratospheric warmings have a well-expressed negative reaction in the D region and a more faintly expressed but also negative reaction in the F region.