Experimental investigation of the coupling process in the middle atmosphere/lower thermosphere/ionosphere system

The paper briefly reviews some investigations realized mainly in Southern Spain of possible coupling between middle atmosphere, lower thermosphere and ionosphere. It draws attention to abnormal circulation changes in the winter stratosphere, detected through variations of D-region ionospheric radiowave absorption; the response of the lower ionosphere to the stratospheric warmings; quasi-periodic fluctuations in ionospheric absorption in relation to planetary wave activity in the stratosphere; the statistically significant correlations between variations of total ozone content considered as a parameter of the stratospheric changes; and radio waves absorption as an indicator of the electron density in the lower ionosphere. There is some difference in the behaviour of the lower ionosphere in relation to meteorological parameters in Southern Spain and Central and East Europe, and this is discussed as partly due to latitudinal variations of ionospheric parameters and to longitudinal inhomogeneity of lower atmosphere processes.