Long-term Evolution of F2-Layer Peak Height
at Various Locations: a Comparison

Thomas Ulich and Esa Turunen

Geophysical Observatory, FIN-99600 Sodankylä, Finland


Increased concentrations of greenhouse gases in the air cause a cooling of the strato-, meso-, and thermosphere (Roble and Dickinson, 1989); the atmosphere is expected to shrink. Rishbeth (1990) predicted a lowering of the peak height of the ionospheric F2-layer which was confirmed for mid-latitudes by Bremer (1992). In the present study we compare long-term data from Sodankylä, Finland, (high latitude, 67.4N, 26.7E) with Bremer's results and other ionosonde records. The evolution of the F2 peak height varies considerably among the stations studied in this work; cooling of the upper atmosphere is not observed at all locations.