Sensitivity study of long-term trends in the F2 layer

ELIAS, ANA G.; ZOSSI, BRUNO S.; FAGRE, MARIANO; SAAVEDRA, ZENON; DE HARO BARBAS, BLAS F.

Montreal

Congreso; 27th IUGG General Assembly; 2019

IUGG

Long-term trends in the Earth?s ionosphere have been of interest since a pioneering study in 1989 suggesting that the long-term increase of greenhouse gases concentration will produce a global cooling in the upper atmosphere together with a global warming in the troposphere. Since then, investigation of long-term changes in the upper atmosphere has become a significant topic in global change research with many results already published. Even though anthropogenic forcing seems to be the main trend driver until now, there are still some inconsistencies and also other forcings of natural origin which are not negligible, such as the secular variation of the Earth´s magnetic field. Values of long-term trends in the F2 layer of the ionosphere depend on several factors. In the case of values obtained from experimental data these can be data origin, completeness and quality, filtering procedure, period of time series, statistical techniques, among others. In the case of values obtained from modeling these factors are mainly parameter values and assumptions. A sensitivity analysis is carried out in this work studying potential changes in trend values observed under modifications of the main factors involved in trend assessment. The addition and modeling of natural sources of ionospheric trends is also analyzed in terms of sensitivity. Our aim is to determine the impact on trend results of the choice of parameter values, of statistical method or of model assumptions in an attempt to contribute to the elucidation of inconsistencies in trends and to determine relative roles of natural forcings.