Intra‐annual variation of wave number 4 structure of vertical <b>E</b> × <b>B</b> drifts in the equatorial ionosphere seen from ROCSAT‐1

Ren, Zhipeng; Wan, Weixing; Liu, Libo; Xiong, Juan

doi:10.1029/2009ja014060

Cited by 66 publications

(104 citation statements)

References 37 publications

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“…As denoted by the thin lines vertical between Figures 4a and 4b, the peak locations of upward E × B drift are close to those of nmf2, at least for the southern EIA crest, while the longitude of the wave 1 peak does not match between the upward E × B drift and the nmf2 at the northern EIA crest; this is discussed later. Compared with observations of vertical drift, the significant existence of the wave 4 structure agrees with existing observations [Hartman and Heelis, 2007;Kil et al, 2007Kil et al, , 2008Ren et al, 2009]. However, the amplitude of wave 4 is considerably lower in our simulation (about 4%) than in the observations (e.g., about 10% is shown in Figure 2 of Ren et al [2009] for a similar local time and season).…”

Section: Resultssupporting

confidence: 67%

“…Compared with observations of vertical drift, the significant existence of the wave 4 structure agrees with existing observations [Hartman and Heelis, 2007;Kil et al, 2007Kil et al, , 2008Ren et al, 2009]. However, the amplitude of wave 4 is considerably lower in our simulation (about 4%) than in the observations (e.g., about 10% is shown in Figure 2 of Ren et al [2009] for a similar local time and season). The wave 1 structure may possibly exist also in the observed distribution, although it has not been featured so far.…”

Section: Resultssupporting

confidence: 67%

“…The nonmigrating tides, with their climatology, have been observed directly in the lower thermosphere [e.g., Oberheide et al, 2006;Forbes et al, 2008], which confirmed the dominant existence of the DE3 tide during many months. As evidence of modulation in the dynamo, a four-peak structure has been observed in E × B drift [Hartman and Heelis, 2007;Kil et al, 2007Kil et al, , 2008Ren et al, 2009] and in the equatorial electrojet (EEJ) [England et al, 2006b;Luhr et al, 2008] and has been shown in electrodynamic simulations [Jin et al, 2008;Ren et al, 2010]. Furthermore, the four-peak structure of the EIA has been reproduced by a simulation using the ThermosphereIonosphere-Mesosphere-Electrodynamics General Circulation Model (TIME-GCM), in which the nonmigrating tidal forcing derived from the Global-Scale Wave Model was incorporated at its lower boundary [Hagan et al, 2007].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Vertical connection from the tropospheric activities to the ionospheric longitudinal structure simulated by a new Earth's whole atmosphere-ionosphere coupled model

et al. 2011

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[1] This paper introduces a new Earth's atmosphere-ionosphere coupled model that treats seamlessly the neutral atmospheric region from the troposphere to the thermosphere as well as the thermosphere-ionosphere interaction including the electrodynamics selfconsistently. The model is especially useful for the study of vertical connection between the meteorological phenomena and the upper atmospheric behaviors. As an initial simulation using the coupled model, we have carried out a 30 day consecutive run in September. The result reveals that the longitudinal structure of the F-region ionosphere varies on a day-to-day basis in a highly complex way and that a four-peak structure of the daytime equatorial ionization anomaly (EIA) similar to the recent observations appears as an averaged feature. The simulation reproduces and thus confirms the vertical coupling processes proposed so far with respect to the formation of the averaged EIA longitudinal structure; the excitation of solar nonmigrating tides in the troposphere, their propagation through the middle atmosphere, and the modulation of ionospheric dynamo, which in turn affects EIA generation. The simulation result indicates that not only the ionospheric averaged longitudinal structure but also the day-to-day variation can be modulated significantly by the lower atmospheric effect.

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Section: Resultssupporting

confidence: 67%

Section: Resultssupporting

confidence: 67%

Section: Introductionmentioning

confidence: 99%

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Vertical connection from the tropospheric activities to the ionospheric longitudinal structure simulated by a new Earth's whole atmosphere-ionosphere coupled model

et al. 2011

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“…The bottom two panels (c) and (f) show the calculated F-region vertical motion at 350 km resulting from a uniform zonal wind of 100 m/s to the west in the morning to the east in the evening local times. The correspondence between O + density enhancements and depletions with the wind induced upward and downward drifts provides a simple illustration of variable background upon which the WN4 variations are also modulated (Hartman and Heelis, 2007;Kil et al, 2008;Ren et al, 2009;Oh et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

WN4 effect on longitudinal distribution of different ion species in the topside ionosphere at low latitudes by means of DEMETER, DMSP-F13 and DMSP-F15 data

et al. 2009

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Abstract. Plasma probe data from DMSP-F13, DMSP-F15 and DEMETER satellites were used to examine longitudinal structures in the topside equatorial ionosphere during fall equinox conditions of 2004 year. Since the launch of DEME-TER satellite on 29 June 2004, all these satellites operate close together in the topside ionosphere. Here, data taken from Special Sensor-Ion, Electron and Scintillations (SSIES) instruments on board DMSP-F13, F15 and Instrument Analyser de Plasma (IAP) on DEMETER, are used. Longitudinal variations in the major ions at two altitudes (∼730 km for DEMETER and ∼840 km for DMSP) are studied to further describe the recently observed "wavenumber-four" (WN4) structures in the equatorial topside ionosphere. Different ion species H + , He + and O + have a rather complex longitudinal behavior. It is shown that WN4 is almost a regular feature in O + the density distribution over all local times covered by these satellites. In the evening local time sector, H + ions follow the O + behavior within WN4 structures up to the premidnight hours. Near sunrise H + and later in the daytime, He + longitudinal variations are out of phase with respect to O + ions and effectively reduce the effect of WN4 on total ion density distribution at altitudes 730-840 km. It is shown that both a WN4 E × B drift driver and local F-region winds must be considered to explain the observed ion composition variations.

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“…We classify the tidal effects into two categories: tidal wind and tidal non-wind effects. As suggested by previous theoretical and model works at equatorial regions (Lühr et al 2007;Jin et al 2008;Brahmanandam et al 2011;Pedatella et al 2012;Ren et al 2009;England et al 2010;Zhang et al 2010;Oberheide et al 2011), lower atmosphere tides could penetrate directly into the thermosphere, leading to an ionospheric longitude variation driven by in situ changes in neutral winds (i.e., tidal wind effect) or neutral composition (i.e., tidal non-wind effect), in addition to the E-F electric field coupling mechanism. In order to investigate the tidal effects, we run the TIEGCM under six conditions: (1-3) without migrating tidal input, and with zero zonal or meridional or neutral wind; (4-6) with migrating tides, and with zero zonal or meridional or neutral wind.…”

Section: Migrating Tidal Effectsmentioning

confidence: 99%

Longitudinal structure in electron density at mid-latitudes: upward-propagating tidal effects

Wang

Zhang

2017

Earth Planets Space

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This work studies the upward-propagating migrating and non-migrating tidal effects from the lower atmosphere on the longitudinal variation of electron density ( Ne) in both the E and F regions at mid-latitudes during the 2002 March equinox. A total of 12 runs are conducted using the Thermosphere Ionosphere Electrodynamic General Circulation model for theoretical investigation. The Ne at altitudes above 200 km is affected by upward-propagating tides, with maximum values attained around 300 km. Migrating tides result in reduced longitudinal differences in the Ne over North America and in the Southern Hemisphere, while non-migrating tides induce a wave-4 pattern in both hemispheres. The non-migrating effect is weaker than the migrating effect after penetrating into the F region. The neutral composition (i.e., ratio of atom oxygen to molecular nitrogen) is dominant in regulating the Ne in both the migrating (accounting for approximately 64%) and non-migrating (about 60%) tidal penetration processes. TheNe caused by the tidal meridional wind (accounting for approximately 70%) is stronger than the tidal zonal wind (about 30%) under both the migrating and non-migrating tidal conditions, except in the Southern Hemisphere under migrating tidal input. This work contributes to our understanding of the mechanisms for the longitudinal modulation of the Ne at mid-latitudes.

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Intra‐annual variation of wave number 4 structure of vertical E × B drifts in the equatorial ionosphere seen from ROCSAT‐1

Cited by 66 publications

References 37 publications

Vertical connection from the tropospheric activities to the ionospheric longitudinal structure simulated by a new Earth's whole atmosphere-ionosphere coupled model

Vertical connection from the tropospheric activities to the ionospheric longitudinal structure simulated by a new Earth's whole atmosphere-ionosphere coupled model

WN4 effect on longitudinal distribution of different ion species in the topside ionosphere at low latitudes by means of DEMETER, DMSP-F13 and DMSP-F15 data

Longitudinal structure in electron density at mid-latitudes: upward-propagating tidal effects

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