Vertical structure of longitudinal differences in electron densities at mid-latitudes

Wang, Hui; Liu, Dingwei; Zhang, Jing

doi:10.1007/s11434-015-0993-7

Cited by 10 publications

(19 citation statements)

References 22 publications

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“…In the Southern Hemisphere, ΔNe at 60° GLon is larger than that at −120° GLon around 10 MLT (type 2) but smaller around 20 MLT (type 1). These longitudinal and diurnal patterns at midlatitudes are consistent with CHAMP and COSMIC observations [ Xiong and Lühr , ; Wang et al , , ].…”

Section: Resultssupporting

confidence: 88%

“…There are distinct longitudinal (zonal) differences in the ionospheric electron density and thermospheric mass density. The midlatitudinal electron density exhibits obvious wave‐2 and wave‐1 variations along geographic longitudes (GLon) in the Northern and Southern Hemispheres, as revealed by observations from both ground‐based Global Positioning Satellite (GPS) receivers and the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) and Challenging Minisatellite Payload (CHAMP) satellites, as well as by global simulations [ Zhang et al , , , ; Xu et al , ; Luan and Dou , ; Xiong and Lühr , ; Wang et al , , ; Wang and Zhang , ]. As its thermospheric counterpart, the mass density exhibits a wave‐1 longitudinal structure, which is almost 180° out of phase in the two hemispheres, as revealed by both CHAMP observations and simulations using the Global Ionosphere‐Thermosphere Model (GITM) [ Xiong et al , ; Wang et al , ].…”

Section: Introductionmentioning

confidence: 99%

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Longitudinal modulation of electron and mass densities at middle and auroral latitudes: Effect of geomagnetic field strength

et al. 2017

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In this study, the effect of a reduction in magnetic field strength on the longitudinal modulation of electron density (ΔNe) and mass density (Δρ) is investigated. We study conditions during the September equinox and June and December solstices at middle and auroral latitudes in both Northern and Southern Hemispheres. The Global Ionosphere‐Thermosphere Model was employed for the theoretical study. Simulations were performed with a realistic International Geomagnetic Reference Field (IGRF) model and an IGRF model reduced in strength by 50%. The reduction in field strength increased the longitudinal variations in ΔNe by 2–34% in the nighttime sector but reduced the variation by 7–20% in the daytime sector at midlatitudes in both hemispheres. Conversely, at auroral latitudes ΔNe was reduced by 2–32% at all local times. The changes during equinoxes are larger than those for the solstices. The differences with local time in the response of ΔNe to a reduction in magnetic field strength were mainly due to changes in the oxygen/molecular nitrogen (O/N2) ratio in the Northern Hemisphere, whereas the differences were due to the combined effects of vertical winds and changes in the O/N2 ratio in the Southern Hemisphere. Both vertical winds and horizontal trueE→×trueB→ convection eliminated ΔNe at high latitudes. Δρ got enhanced at both middle and auroral latitudes, which was related to the enhanced Joule heating effect when the magnetic field was reduced.

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Section: Resultssupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Longitudinal modulation of electron and mass densities at middle and auroral latitudes: Effect of geomagnetic field strength

et al. 2017

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“…Previous regional and global observations have disclosed prominent wave-2 and wave-1 longitudinal structures of the Ne in the F layer in the Northern and Southern Hemispheres Zhao et al 2013;Xu et al 2013;Wang et al 2016). Wang et al (2016) found a wave-1 longitudinal structure of Ne existing in the E layer in both hemispheres. The longitudinal variation of thermosphere and ionospheric parameters are often related to non-migrating tides, either generated in situ or upward-propagated from the lower atmosphere (Wu et al 2012).…”

Section: Introductionmentioning

confidence: 77%

“…The wave amplitudes are larger in the Southern than in the Northern Hemisphere. Wang et al (2016) showed that such longitudinal and diurnal features existed throughout the whole year and for all solar activity levels. Wang and Liu (2015) indicated that local physical processes (i.e., thermospheric neutral wind and solar heating) contributed to the observed longitudinal structure of the Ne.…”

Section: Data-model Comparisonmentioning

confidence: 86%

“…Meridional wind, neutral composition, and solar heating are responsible for the remnant. In the E layer, the dominant in situ process is solar heating (Wang et al 2016). These results indicate that local/in situ physical processes contribute to observed longitudinal variations of Ne in both the E and F regions and can compromise the modelobservation differences.…”

Section: Introductionmentioning

confidence: 99%

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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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Study on ionosphere change over Shandong based from SDCORS in 2012

Guo

Dong

Liu

et al. 2017

Geodesy and Geodynamics

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Vertical structure of longitudinal differences in electron densities at mid-latitudes

Cited by 10 publications

References 22 publications

Longitudinal modulation of electron and mass densities at middle and auroral latitudes: Effect of geomagnetic field strength

Longitudinal modulation of electron and mass densities at middle and auroral latitudes: Effect of geomagnetic field strength

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

Study on ionosphere change over Shandong based from SDCORS in 2012

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