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Thermospheric parameters long‐term variations retrieved from ionospheric observations in Europe
Author(s) -
Mikhailov A. V.,
Perrone L.
Publication year - 2016
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2016ja023234
Subject(s) - ionosonde , solar cycle , solar maximum , atmospheric sciences , solar minimum , ionosphere , solar cycle 22 , thermosphere , environmental science , exosphere , earth's magnetic field , term (time) , climatology , meteorology , physics , geology , astronomy , solar wind , electron density , quantum mechanics , magnetic field , ion , electron
Abstract Recently developed method to retrieve thermospheric parameters ( T ex , O, O 2 , and N 2 ) and the total solar EUV flux with λ < 1050 Å from routine f o F 1 ionosonde observations has been applied to monthly median f o F 1 data on Rome, Slough/Chilton, and Juliusruh stations to analyze long‐term trends in the thermospheric parameters. For the first time exospheric temperature and neutral composition were obtained for June noontime conditions over the period of ~ 5 solar cycles. The retrieved parameter manifested solar cycle and long‐term (some solar cycles) variations with a rising phase in 1965–1985 and falling phase in 1985–2008. The retrieved thermospheric parameters were shown to be close to the MSIS‐86 model ones exhibiting very small (<1% per decade) and statistically insignificant linear trends estimated either over all 56 years or only over the years of solar minimum. No peculiarities in long‐term variations in relation with the last deep solar minimum have been revealed. The source of the thermospheric parameter long‐term trends is the Sun, i.e., they have a natural (not anthropogenic) origin and are mainly controlled by long‐term variations of solar and geomagnetic activity.