Geomagnetic control of the midlatitude foF1 and foF2 long‐term variations: Recent observations in Europe

Perrone, Loredana; Михайлов, А. А.

doi:10.1002/2016ja022715

Cited by 18 publications

(18 citation statements)

References 49 publications

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“…Moving to the ionospheric trends which should reflect the thermospheric trends at least at middle latitudes during daytime hours, we see a contradiction with the CO 2 increase hypothesis [ Perrone and Mikhailov , ; Mikhailov and Perrone , ]. The most essential ionospheric effect of CO 2 cooling should be seen in h m F 2 decrease.…”

Section: Discussioncontrasting

confidence: 72%

Thermospheric parameters long‐term variations retrieved from ionospheric observations in Europe

Mikhailov

Perrone

2016

JGR Space Physics

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Recently developed method to retrieve thermospheric parameters (Tex, O, O2, and N2) and the total solar EUV flux with λ < 1050 Å from routine foF1 ionosonde observations has been applied to monthly median foF1 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.

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Section: Discussioncontrasting

confidence: 72%

Thermospheric parameters long‐term variations retrieved from ionospheric observations in Europe

Mikhailov

Perrone

2016

JGR Space Physics

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“…It should be mentioned that Danilov and Konstantinova (2014) were the first who have proposed to relate negative f o F 2 trends with the atomic oxygen decrease in the upper atmosphere, but they prescribe this decrease to the intensification of the eddy diffusion. It was suggested by Mikhailov and Perrone (2016) that atomic oxygen long-term variation in was due to the corresponding long-term variations in solar activity.…”

Section: Discussionmentioning

confidence: 99%

“…But their results have stimulated researchers to relate the observed ionospheric long-term trends to the thermosphere greenhouse cooling (Ulich & Turunen, 1997;Sharma et al, 1999;Alfonsi et al, 2001Alfonsi et al, , 2002La stovička et al, 2008;Qian et al, 2008Qian et al, , 2009La stovička et al, 2012;Danilov & Konstantinova, 2013;Mielich & Bremer, 2013;Konstantinova & Danilov, 2015;Roininen et al, 2015). The mechanisms of the thermospheric and ionospheric trends may be different and serious contradictions with the CO 2 hypothesis confirm this (Perrone & Mikhailov, 2016). It is well-known that the ionospheric F-layer is strongly controlled by geomagnetic activity and nobody has denied yet the geomagnetic control concept of ionospheric long-term trends (Mikhailov, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…It is well-known that the ionospheric F-layer is strongly controlled by geomagnetic activity and nobody has denied yet the geomagnetic control concept of ionospheric long-term trends (Mikhailov, 2002). The analysis by Perrone & Mikhailov (2016) using all available (including recent ones) f o F 1 and f o F 2 observations on Slough/Chilton and Juliusruh ionosonde stations has confirmed that the geomagnetic control of the f o F 2 and f o F 1 long-term variations was still valid in the 21st century. Moreover the dependence on geomagnetic activity has become more pronounced and explicit after 1990.…”

Section: Introductionmentioning

confidence: 99%

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Long-term variations of the upper atmosphere parameters on Rome ionosonde observations and their interpretation

Perrone

Mikhailov

Cesaroni

et al. 2017

J. Space Weather Space Clim.

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-A recently proposed self-consistent approach to the analysis of thermospheric and ionospheric long-term trends has been applied to Rome ionosonde summer noontime observations for the period. This approach includes: (i) a method to extract ionospheric parameter long-term variations; (ii) a method to retrieve from observed f o F 1 neutral composition (O, O 2 , N 2 ), exospheric temperature, Tex and the total solar EUV flux with l < 1050 Å; and (iii) a combined analysis of the ionospheric and thermospheric parameter long-term variations using the theory of ionospheric F-layer formation. Atomic oxygen, [O] period which is mainly due to atomic oxygen decrease after ∼1990. A linear trend in (dh m F 2 ) 11y estimated over the period is very small and insignificant reflecting the absence of any significant trend in neutral temperature. The retrieved neutral gas density, r atomic oxygen, [O] and exospheric temperature, Tex long-term variations are controlled by solar and geomagnetic activity, i.e. they have a natural origin. The residual trends estimated over the period of ∼5 solar cycles are very small (<0.5% per decade) and statistically.

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“…The impact of Ap on yearly values of foE was found to be quite negligible, and it is not considered further, as was the case in foF2 solar corrections (e.g. Laštovička et al, 2006;Perrone and Mikhailov, 2016). foF2 from Slough/Chilton is used in the same way as foE to check the impact of changing solar correction on foF2 trend calculations.…”

Section: Methodsmentioning

confidence: 99%

Stability of solar correction for calculating ionospheric trends

et al. 2016

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Abstract. Global climate change affects the whole atmosphere, including the thermosphere and ionosphere. Calculations of long-term trends in the ionosphere are critically dependent on solar activity (solar cycle) correction of ionospheric input data. The standard technique is to establish an experimental model via calculating the dependence of ionospheric parameter on solar activity from the whole analysed data set, subtract these model data from observed data and analyse the trend of residuals. However, if the solar activity dependence changes with time, the solar correction calculated from the whole data set may result in miscalculating the ionospheric trends. To test this, data from two European ionospheric stations -Juliusruh and Slough/Chilton -which provide long-term reliable data, have been used for the period 1975-2014. The main result of this study is the finding that the solar activity correction used in calculating ionospheric long-term trends need not be stable, as was assumed in all previous investigations of ionospheric trends. During the previous solar cycle 23 and the current solar cycle 24, the solar activity correction appears to be different from that for the previous period and the Sun seems to behave in a different way than throughout the whole previous era of ionospheric measurements. In future ionospheric trend investigations the non-stability of solar activity correction has to be very seriously taken into account, because it can substantially affect calculated long-term trends of ionospheric parameters.

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Geomagnetic control of the midlatitude f_oF₁ and f_oF₂ long‐term variations: Recent observations in Europe

Cited by 18 publications

References 49 publications

Thermospheric parameters long‐term variations retrieved from ionospheric observations in Europe

Thermospheric parameters long‐term variations retrieved from ionospheric observations in Europe

Long-term variations of the upper atmosphere parameters on Rome ionosonde observations and their interpretation

Stability of solar correction for calculating ionospheric trends

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