The seasonal behavior of high‐latitude thermospheric winds and ion velocities observed over one solar cycle

Aruliah, A. L.; Farmer, A. D.; Rees, D.; Brändström, U.

doi:10.1029/96ja00360

Cited by 57 publications

(71 citation statements)

References 19 publications

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“…The spring winds are larger than the autumn ones, especially during solar active periods. This is in agreement with the results of Aruliah et al (1996). These maximum values are always reached before 0 UT.…”

Section: Daily Variations At 257 Km Heightsupporting

confidence: 82%

“…The di erences could be explained because the weakness of the HWM model is a lack of data from high-latitude facilities. It is also worthwhile to compare our results with the recent study of the high-latitude thermospheric neutral wind deduced from a Fabry-Perot interferometer (FPI) over a full solar cycle (Aruliah et al, 1996). The authors showed that the March equinox nighttime winds are larger than the September equinox winds during high and low solar activities.…”

Section: The Modelmentioning

confidence: 67%

“…In contrast these authors did not ®nd any dependence of this time with the solar¯ux, but the main disagreement between both studies is the amplitude of the equatorward nighttime winds, which can be almost a factor two larger in our study. The weaknesses of FPI measurements have been extensively discussed in Aruliah et al (1996), and we have already outline in Sect. 2 the small uncertainties of our method.…”

Section: The Modelmentioning

confidence: 99%

“…Previous studies split the meridional winds according to two geophysical parameters A p and f 10.7 , (e.g., Duboin and Lafeuille, 1992;Aruliah et al, 1996), where f 10.7 represents the solar activity and A p represents the geomagnetic activity. Figure 3 shows mean winds at 257 km height for high solar¯uxes and two geomagnetic activities (A p < 11 and A p > 11).…”

Section: Determination Of the Eight Classes Of Windmentioning

confidence: 99%

“…Recently, Aruliah et al (1996) studied the wind over a full solar cycle, and showed it to have an equinoctial asymmetry not predicted by any numerical simulations. Hedin et al (1991) published a model for thermospheric wind based on data from satellites and ground-based observations.…”

Section: Introductionmentioning

confidence: 99%

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Meridional thermospheric neutral wind at high latitude over a full solar cycle

et al. 1998

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Abstract. EISCAT radar experiments over a full solar cycle between January 1984 and March 1995 have been used to construct meridional neutral wind patterns in the ionospheric F region. For locally geomagnetically quiet periods the neutral winds have been binned according to season, solar activity, and universal time. The diurnal and seasonal behaviors and the e ect of the solar¯ux are described. An empirical model of the meridional neutral wind for the high latitudes at eight altitudes in the ionospheric F region over a full solar cycle is presented. Results are compared with other recent empirical models.

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Section: Daily Variations At 257 Km Heightsupporting

confidence: 82%

Section: The Modelmentioning

confidence: 67%

Section: The Modelmentioning

confidence: 99%

Section: Determination Of the Eight Classes Of Windmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Meridional thermospheric neutral wind at high latitude over a full solar cycle

et al. 1998

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First observation of the anomalous electric field in the topside ionosphere by ionospheric modification over EISCAT

Kosch

Vickers

Ogawa

et al. 2014

Geophysical Research Letters

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We have developed an active ground-based technique to estimate the steady state field-aligned anomalous electric field (E*) in the topside ionosphere, up to~600 km, using the European Incoherent Scatter (EISCAT) ionospheric modification facility and UHF incoherent scatter radar. When pumping the ionosphere with high-power high-frequency radio waves, the F region electron temperature is significantly raised, increasing the plasma pressure gradient in the topside ionosphere, resulting in ion upflow along the magnetic field line. We estimate E* using a modified ion momentum equation and the Mass Spectrometer Incoherent Scatter model. From an experiment on 23 October 2013, E* points downward with an average amplitude of 1.6 μV/m, becoming weaker at higher altitudes. The mechanism for anomalous resistivity is thought to be low-frequency ion acoustic waves generated by the pump-induced flux of suprathermal electrons. These high-energy electrons are produced near the pump wave reflection altitude by plasma resonance and also result in observed artificially induced optical emissions.

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Seasonal variation and solar activity dependence of the quiet‐time ionospheric trough

et al. 2014

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We have conducted a statistical analysis of the ionospheric F region trough, focusing on its seasonal variation and solar activity dependence under geomagnetically quiet and moderate conditions, using plasma parameter data obtained via Common Program 3 observations performed by the European Incoherent Scatter (EISCAT) radar between 1982 and 2011. We have confirmed that there is a major difference in frictional heating between the high-and low-latitude sides of the EISCAT field of view (FOV) at 73°0′N-60°5′N (geomagnetic latitude) at an altitude of 325 km, which is associated with trough formation. Our statistical results show that the high-latitude and midlatitude troughs occur on the high-and low-latitude sides of the FOV, respectively. Seasonal variations indicate that dissociative recombination accompanied by frictional heating is a main cause of trough formation in sunlit regions. During summer, therefore, the occurrence rate is maintained at 80-90% in the postmidnight high-latitude region owing to frictional heating by eastward return flow. Solar activity dependence on trough formation indicates that field-aligned currents modulate the occurrence rate of the trough during the winter and equinox seasons. In addition, the trough becomes deeper via dissociative recombination caused by an increased ion temperature with F 10.7 , at least in the equinox and summer seasons but not in winter.

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The seasonal behavior of high‐latitude thermospheric winds and ion velocities observed over one solar cycle

Cited by 57 publications

References 19 publications

Meridional thermospheric neutral wind at high latitude over a full solar cycle

Meridional thermospheric neutral wind at high latitude over a full solar cycle

First observation of the anomalous electric field in the topside ionosphere by ionospheric modification over EISCAT

Seasonal variation and solar activity dependence of the quiet‐time ionospheric trough

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