Tendencias a largo plazo en la región F2 de la ionosfera y su relación con la actividad geomagnética.

Abstract

Using a new approach, Mikhailov and Marin (2000) and Marin a al. (2000) analy sed respectively the long-term trends of tbe F2-layer cnitical frequency and height, foF2 and hmF2, on Northern Hemisphere jonosonde stations over the time peniod 1965-1991. Whereas tbe majority of te observedfoF2 trends were found tobe negati ve, te hnzF2 ones were seen to be positive. A global warming in the lower atmosphere, accompanied by a cooling in the upper atmospbere, due to tSe greenhouse effect can not be te cause of te detected trends. A thermospheric temperature decrease would result in negative hmF2 trends and positivefoF2 trends, contrary to the observations both in foF2 and hmF2. Rut such long-íerm trends can be explained by an increase of te F2-la Física de la Tierra 263 2000,12,263-280 D. Marín y otros Tendencia a largo plazo en la región F2... yer storm activity as a result of the increasing geomagnetic activity observed during the analysed time period 1965-1991.