The influence of nonmigrating tides on the longitudinal variation of the equatorial electrojet

Lühr, H.; Rother, M.; Häusler, K.; Alken, Patrick; Maus, Stefan

doi:10.1029/2008ja013064

Cited by 151 publications

(193 citation statements)

References 18 publications

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“…DE3 "wave-4" structure has been found in many ionospheric data sets, including the EEF, equatorial electrojet current, and vertical ion drift velocities England et al, 2006;Alken and Maus, 2007;Lühr et al, 2008;Fejer et al, 2008;Alken and Maus, 2010b]. The wave-4 structure typically contains maxima over both Africa and South America.…”

Section: Discussionmentioning

confidence: 99%

“…This work represents the first time this method has been applied and validated outside the Peruvian longitude sector. We then analyze our data set of EEF estimates to study the longitudinal and seasonal variability of the ionosphere and the influence of global atmospheric tides on ionospheric dynamics, which has recently been shown to significantly impact equatorial ionospheric structure [Forbes et al, 2008;Lühr et al, 2008]. This method will also enable future analyses of the behavior of ionospheric dynamics during storms.…”

Section: Introductionmentioning

confidence: 99%

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Longitudinal and seasonal structure of the ionospheric equatorial electric field

Alken¹,

Chulliat

Maus³

2013

JGR Space Physics

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[1] The daytime eastward equatorial electric field (EEF) in the ionospheric E-region plays an important role in equatorial ionospheric dynamics. It is responsible for driving the equatorial electrojet (EEJ) current system, equatorial vertical ion drifts, and the equatorial ionization anomaly. Due to its importance, there is much interest in accurately measuring and modeling the EEF. In this work we propose a method of estimating the EEF using CHAMP satellite-derived latitudinal current profiles of the daytime EEJ along with Δ H measurements from ground magnetometer stations. Magnetometer station pairs in both Africa and South America were used for this study to produce time series of electrojet current profiles. These current profiles were then inverted for estimates of the EEF by solving the governing electrostatic equations. We compare our results with the Ion Velocity Meter (IVM) instrument on board the Communication/Navigation Outage Forecasting System satellite. We find high correlations of about 80% with the IVM data; however, we also find a constant offset of about 0.3 mV/m between the two data sets in Africa. Further investigation is needed to determine its cause. We compare the EEF structure in Africa and South America and find differences which can be attributed to the effect of atmospheric nonmigrating tides. This technique can be extended to any pair of ground magnetometer stations which can capture the day-to-day strength of the EEJ.Citation: Alken, P., A. Chulliat, and S. Maus (2013), Longitudinal and seasonal structure of the ionospheric equatorial electric field,

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Longitudinal and seasonal structure of the ionospheric equatorial electric field

Alken¹,

Chulliat

Maus³

2013

JGR Space Physics

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“…The phase of the SPW defines the longitude where the wave crest occurs. At low and equatorial latitudes the WN4/WN3 patterns of the ionospheric and thermospheric quantities and the related tidal components have been widely studied (Sagawa et al, 2005;Immel et al, 2006;England et al, 2006England et al, , 2010Lühr et al, 2008Lühr et al, , 2012Kil et al, 2007;Häusler and Lühr, 2009;Zhang et al, 2010;Xiong and Lühr, 2013;. These tides originate from the lower atmosphere and can propagate upward to the upper atmosphere, either by direct propagation or through the E region wind dynamo coupling mechanism (e.g.…”

Section: Y-l Zhou Et Al: Solar Activity Dependence Of Nonmigratingmentioning

confidence: 99%

The solar activity dependence of nonmigrating tides in electron density at low and middle latitudes observed by CHAMP and GRACE

et al. 2016

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Abstract. In this paper we use more than a decade of in situ electron density observations from CHAMP and GRACE satellites to investigate the solar activity dependence of nonmigrating tides at both low and middle latitudes. The results indicate that the longitudinal patterns of F region electron density vary with season and latitude, which are exhibiting a wavenumber 4 (WN4) pattern around September equinox at low latitudes and WN1/WN2 patterns during local summer at the southern/northern middle latitudes. These wave patterns in the F region ionosphere can clearly be seen during both solar maximum and minimum years. At low latitudes the absolute amplitudes of DE3 (contributing to the WN4 pattern) are found to be highly related to the solar activity, showing larger amplitudes during solar maximum years. Similarly a solar activity dependence can also be found for the absolute amplitudes of D0, DW2 and DE1 (contributing to the WN1 and WN2 pattern) at middle latitudes. The relative amplitudes (normalized by the zonal mean) of these nonmigrating tides at both low and middle altitudes show little dependence on solar activity. We further found a clear modulation by the quasi-biennial oscillation (QBO) of the relative DE3 amplitudes in both satellite observations, which is consistent with the QBO dependence as reported for the E region temperatures and zonal wind. It also supports the strong coupling of the low-latitude nonmigrating tidal activity between the E and F regions. However, the QBO dependence cannot be found for the relative amplitudes of the nonmigrating tides at middle latitudes, which implies that these tides are generated in situ at F region altitudes.

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“…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%

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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The influence of nonmigrating tides on the longitudinal variation of the equatorial electrojet

Cited by 151 publications

References 18 publications

Longitudinal and seasonal structure of the ionospheric equatorial electric field

Longitudinal and seasonal structure of the ionospheric equatorial electric field

The solar activity dependence of nonmigrating tides in electron density at low and middle latitudes observed by CHAMP and GRACE

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

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