Solar cycle dependence of winds in the lower ionosphere

Sprenger, K.; Schminder, R.

doi:10.1016/0021-9169(69)90100-7

Cited by 56 publications

(34 citation statements)

References 3 publications

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“…At different heights the correlations are different, and nearly all are nonsignificant. Above 80 km the derived correlations are negative and in general agreement with most reported values for these heights by other authors (Sprenger and Schminder, 1969;Greisiger et al, 1987;Namboothiri et al, 1993Namboothiri et al, , 1994Bremer et al, 1997;Baumgaertner et al, 2005;Portnyagin et al, 2006). Only Fraser (1990) and Jacobi and Kürschner (2006) derived positive correlations.…”

Section: Influence Of the 11-year Solar Cyclesupporting

confidence: 91%

“…5 and 7). This positive correlation is confirmed by a lot of other investigations (Sprenger and Schminder, 1969;Dartt et al, 1983;Namboothiri et al, 1993Namboothiri et al, , 1994Bremer et al, 1997;Jacobi and Kürschner, 2006). A negative correlation was only derived by Greisiger et al (1987), Merzlyakov and Portnyagin (1999), and Middleton et al (2002).…”

Section: Influence Of the 11-year Solar Cyclesupporting

confidence: 69%

“…These results were confirmed by observations at other stations (Dartt et al, 1983). However, Greisiger et al (1987) achieved partly different results when they investigated a longer time series than that used by Sprenger and Schminder (1969), also including additional meteor radar wind observations. Their correlations between the zonal wind and the solar activity were different depending on the time period investigated.…”

Section: Introductionmentioning

confidence: 54%

“…Therefore, the significance level during winter is mostly below 90%. Other authors found similar results for summer (Dartt et al, 1983;Jacobi, 1998;Merzlyakov and Portnyagin, 1999) and winter (Sprenger and Schminder, 1969;Bremer et al, 1997;Jacobi, 1998;Jacobi and Kürschner, 2006). But there are also some authors who found opposite results or no correlations.…”

Section: Influence Of the 11-year Solar Cyclementioning

confidence: 68%

“…The first investigations of the influence of the solar activity on the wind field of the mesosphere and lower thermosphere (MLT region) were published by Sprenger and Schminder (1969), using LF wind observations at mid-latitudes from 1957 until 1968. They found positive correlations between solar activity and zonal as well as meridional winds during winter and a negative correlation between the amplitude of the semidiurnal tidal component and the solar activity.…”

Section: Introductionmentioning

confidence: 99%

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Long-term variations of the mesospheric wind field at mid-latitudes

Keuer¹,

Hoffmann²,

Singer³

et al. 2007

Ann. Geophys.

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Abstract. Continuous MF radar observations at the station Juliusruh (54.6 • N; 13.4 • E) have been analysed for the time interval between 1990 and 2005, to obtain information about solar activity-induced variations, as well as long-term trends in the mesospheric wind field. Using monthly median values of the zonal and the meridional prevailing wind components, as well as of the amplitude of the semidiurnal tide, regression analyses have been carried out with a dependence on solar activity and time. The solar activity causes a significant amplification of the zonal winds during summer (increasing easterly winds) and winter (increasing westerly winds). The meridional wind component is positively correlated with the solar activity during summer but during winter the correlation is very small and non significant. Also, the solar influence upon the amplitude of the semidiurnal tidal component is relatively small (in dependence on height partly positive and partly negative) and mostly non-significant.The derived trends in the zonal wind component during summer are below an altitude of about 83 km negative and above this height positive. During the winter months the trends are nearly opposite compared with the trends in summer (transition height near 86 km). The trends in the meridional wind components are below about 85 km positive in summer (significant) and near zero (nonsignificant) in winter; above this height during both seasons negative trends have been detected. The trends in the semidiurnal tidal amplitude are at all heights positive, but only partly significant.The detected trends and solar cycle dependencies are compared with other experimental results and model calculations. There is no full agreement between the different results, probably caused by different measuring techniques and evaluation methods used. Also, different heights and observation periods investigated may contribute to the detected differences.

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Section: Influence Of the 11-year Solar Cyclesupporting

confidence: 91%

Section: Influence Of the 11-year Solar Cyclesupporting

confidence: 69%

Section: Introductionmentioning

confidence: 54%

Section: Influence Of the 11-year Solar Cyclementioning

confidence: 68%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Long-term variations of the mesospheric wind field at mid-latitudes

Keuer¹,

Hoffmann²,

Singer³

et al. 2007

Ann. Geophys.

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Interannual variability of the 12-hour tide in the mesosphere and lower thermosphere in 15 years of meteor-radar observations over Rothera (68S, 68W)

Dempsey

Noble

Mitchell

et al. 2022

Preprint

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Wavelet analysis on transient behaviour of tidal amplitude fluctuations observed by meteor radar in the lower thermosphere above Bulgaria

Pancheva

Mukhtarov

2000

Ann. Geophys.

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Abstract. On the basis of bispectral analysis applied to the hourly data set of neutral wind measured by meteor radar in the MLT region above Bulgaria it was demonstrated that nonlinear processes are frequently and regularly acting in the mesopause region. They contribute significantly to the short-term tidal variability and are apparently responsible for the observed complicated behavior of the tidal characteristics. A Morlet wavelet transform is proposed as a technique for studying nonstationary signals. By simulated data it was revealed that the Morlet wavelet transform is especially convenient for analyzing signals with: (1) a wide range of dominant frequencies which are localized in different time intervals; (2) amplitude and frequency modulated spectral components, and (3) singular, wave-like events, observed in the neutral wind of the MLT region and connected mainly with large-scale disturbances propagated from below. By applying a Morlet wavelet transform to the hourly values of the amplitudes of diurnal and semidiurnal tides the basic oscillations with periods of planetary waves (1.5-20 days), as well as their development in time, are obtained. A cross-wavelet analysis is used to clarify the relation between the tidal and mean neutral wind variability. The results of bispectral analysis indicate which planetary waves participated in the nonlinear coupling with the atmospheric tides, while the results of cross-wavelet analysis outline their time intervals if these interactions are local.Key words: Meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides) - Radio science (nonlinear phenomena)

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Solar cycle dependence of winds in the lower ionosphere

Cited by 56 publications

References 3 publications

Long-term variations of the mesospheric wind field at mid-latitudes

Long-term variations of the mesospheric wind field at mid-latitudes

Interannual variability of the 12-hour tide in the mesosphere and lower thermosphere in 15 years of meteor-radar observations over Rothera (68S, 68W)

Wavelet analysis on transient behaviour of tidal amplitude fluctuations observed by meteor radar in the lower thermosphere above Bulgaria

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