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A theoretical model for mid-and low-latitude ionospheric electric fields in realistic geomagnetic fields

chinese Science Bulletin 2008年第24期53卷 3883-3890页

作者： ren zhipeng wan weixing wei yong liu libo yu tao beijing observatory for space environment Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Wuhan institute of Physics and Mathematics Chinese Academy of Sciences Wuhan 430071 China Graduate School of chinese academy of sciences Beijing 100049 China National Center for space Weather China Meteorological Administration Beijing 100081 China

The geomagnetic fields,which play important roles in the ionospheric dynamo,can greatly affect the global distribution of ionospheric electric fields,currents and other ionospheric electrodynamics *** the study of ionospheric electrodynamics phenomena,such as the longitudinal variations of ionospheric electric fields,the non-dipolar component of the geomagnetic fields must be taken into *** this paper,we deduce a theoretical electric field model for ionospheric dynamo at mid-and low-latitude which adopt a modified magnetic apex coordinates *** the new electric field model,the geomagnetic fields can be calculated from either the IGRF model or the dipole field model,and the neutral winds and conductivities are calculated based on empirical *** the dynamo equation for the electric potential is finally solved in terms of the line-by-line iteration method,and the ionospheric electric fields and currents are derived from the calculated *** model can reproduce the main features of the ionospheric electrodynamics processes,so it will be a useful tool for the investigation of the upper atmosphere and ionosphere.

关键词：中低纬度电子场磁场地理学

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Simulated longitudinal variations in the lower thermospheric nitric oxide induced by nonmigrating tides

Simulated longitudinal variations in the lower thermospheric...

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中国科学院地质与地球物理研究所第11届（2011年度）学术年会

作者： zhipeng ren,weixing wan,libo liu,and Jiangang Xiong 1 beijing National observatory of space environment,institute of geology and geophysics,chinese academy of sciences,beijing,china.

[1]On the basis of the GCITEM-IGGCAS model and tides from TIMED/SABER observations,the longitudinal variations in the lower thermosphere nitric oxide(NO), which is induced by nonmigrating tides,are *** simulate the intra-annual variation of the NO density and find that equinoctial lower thermospheric NO density shows an obvious wave number 4 longitudinal structure both in equinox and in June solstice and a wave number 3 longitudinal structure in December *** simulation results are consistent with the longitudinal variation observed by Oberheide and Forbes(2008b).The simulations support that the wave number 4 structure in NO density is mainly driven by the eastward propagating nonmigrating diurnal tide with zonal wave number 3,and the wave number 3 structure is mainly driven by the eastward propagating nonmigrating diurnal tide with zonal wave number *** simulations also show that the NO density residuals and the neutral mass density residuals in the height range between 90 and 120 km agree well with each other,and the neutral mass density mainly affects the longitudinal variations of lower thermospheric NO density through modulation of the chemical production rate,e.g.,through affecting the chemical reaction between excited nitrogen and molecular oxygen.

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Equinoctial asymmetry of ionospheric vertical plasma drifts and its effect on F-region plasma density

Equinoctial asymmetry of ionospheric vertical plasma drifts ...

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中国科学院地质与地球物理研究所第11届（2011年度）学术年会

作者： zhipeng ren,weixing wan,libo liu,Yiding Chen,and Huijun Le 1 beijing National observatory of space environment,institute of geology and geophysics,chinese academy of sciences,beijing,china.

[1]The equinoctial asymmetry of the ionospheric vertical E×B plasma drift velocity (Vin the equatorial F region is investigated based on observations from ROCSAT-1 during 1999 to *** is found that the observed asymmetry exhibits obvious local time dependence with three noticeable ***,in the Eastern Hemisphere during the interval between 0900 and 1300 LT,Vis obviously higher at the northern spring equinox (March-April) than at the autumn equinox(September-October).Second,there is a pronounced asymmetry for wave number 4 longitudinal structures of V,which exist almost throughout the daytime and even extend into the evening sector at autumn equinox, while they appear mainly at noon and prenoon at spring ***,around sunset we find an obvious asymmetry of the prereversal enhancement(PRE);the maximum PRE velocity is higher at autumn than at spring equinox in the longitude range from 320°to 150°,and the opposite situation occurs at other *** the basis of the drift observation mentioned,we also simulate the effect of the Vasymmetry on the ionospheric plasma density by running the Theoretical Ionospheric Model of the Earth, institute of geology and geophysics,chinese academy of sciences(TIME-IGGCAS).It is found that the daytime Vasymmetry can partly explain the equinoctial asymmetry in daytime low-latitude ionospheric plasma density observed by *** et al.(***., 115,A09307).

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Correlation between ionospheric longitudinal harmonic components and upper atmospheric tides

Correlation between ionospheric longitudinal harmonic compon...

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中国科学院地质与地球物理研究所第十届(2010年度)学术年会

作者： MU WenFeng~(1,2),wan weixing~(1*),ren zhipeng~1 & XIONG JianGang~1 1 beijing National observatory of space environment,institute of geology and geophysics,chinese academy of sciences,beijing 100029,china 2 Graduate University of chinese academy of sciences,beijing 100049,china

There is strong correlation among the ionospheric longitudinal structures of wavenumber-3(WN3),wavenumber-4(WN4),and eastward-propagating diurnal tides with zonal wave numbers s = 2 and 3(DE2 and DE3) in the upper *** total electron content derived from the Global Ionospheric Maps of the Jet Propulsion Laboratory is used to deduce the latitudinally total electron content(ITEC) in the low-latitude ionosphere,and TIDE/TIMED observations are employed to obtain zonal and meridian winds of the mesopause and lower *** Fourier transformation,various ionospheric longitudinal harmonic components and tidal patterns are derived from the ionospheric and upper-atmospheric observations,and we compare the annual /inter-annual variations in ionospheric harmonic components WN3 and WN4 with those in atmospheric tides(DE2 and DE3). It is found that the annual and inter-annual variations in WN3 and WN4 are consistent with those in DE2 and DE3 zonal wind components respectively,while they are inconsistent with those in the meridian *** then decompose the harmonic components into"tidal patterns",finding that the"DE2"and"DE3"patterns are the main parts of WN3 and WN4 respectively. Their annual and inter-annual variations are similar to those of atmospheric tidal patterns(DE2 and DE3).Complex correlation results show that correlation between the ionospheric"DE2"in WN3 and the atmospheric tidal DE2 zonal wind component is quite strong in the Northern Hemisphere,while that between the ionospheric"DE3"in WN4 and the atmospheric tidal DE3 zonal wind component is much stronger at low *** the same time,the contribution of the meridian wind component is very *** all,the atmospheric tidal DE2 and DE3 patterns are important factors of the ionospheric WN3 and WN4 structures.

关键词： ionospheric longitudinal variation non-migrating tides ionosphere-atmosphere coupling ITEC DE2 DE3

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Simulated wave number 4 structure in equatorial F-region vertical plasma drifts

Simulated wave number 4 structure in equatorial F-region ver...

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中国科学院地质与地球物理研究所第十届(2010年度)学术年会

作者： zhipeng ren,weixing wan,Jiangang Xiong,and libo liu 1 beijing National observatory of space environment,institute of geology and geophysics,chinese academy of sciences,beijing,china. 2 Also at Wuhan institute of Physics and Mathematics,chinese academy of sciences,Wuhan,china. 3 Also at Graduate School of chinese academy of sciences,beijing, china.

[1]This article investigates the wave number 4 longitudinal structure in equatorial vertical E×B plasma drifts(V),using the Theoretical Ionospheric Dynamo Model,institute of geology and geophysics,chinese academy of sciences,Version II model and the DE3 tide wind from the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED)/TIMED Doppler interferometer(TIDI) *** simulate this longitudinal structure and examine its intra-annual variations and the effect of different DE3 tide components and of different current components on *** find that this longitudinal structure shows obvious intra-annual variation,being strongest in northern summer and autumn and weakest in northern *** result is consistent with the intra-annual variation observed by ren et al.(2009b).Our simulations also suggest that the eastward propagation of the DE3 tide can cause the eastward shift of the wave number 4 structure in *** wave number 4 structures in Vare mainly driven by a zonal wind component of DE3 tide,which contributes much more than the meridional wind component of DE3 tide to the wave number 4 structure in *** the influence of the coupling of ionospheric electric fields along the highly conducting magnetic field lines,the symmetric wind component of DE3 tide plays a more important role in the wave number 4 structure in Vthan the antisymmetric component *** intra-annual variations of the wave number 4 structure in Vare mainly controlled by the symmetric wind component of DE3 tide. Our simulations also suggest that the wave number 4 structures in Vare mainly driven by the Hall current.

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A theoretical model for mid-and low-latitude ionospheric electric fields in realistic geomagnetic fields

A theoretical model for mid-and low-latitude ionospheric ele...

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中国科学院地质与地球物理研究所2008学术年会

作者： ren zhipeng~(1,2,3),wan weixing~(1+),wei yong~(1,2,3),liu libo~1 & yu tao~(1,4) 1 beijing observatory for space environment,institute of geology and geophysics,chinese academy of sciences,beijing 100029, china 2 Wuhan institute of Physics and Mathematics,chinese academy of sciences,Wuhan 430071,china 3 Graduate School of chinese academy of sciences,beijing 100049,china 4 National Center for space Weather,china Meteorological Administration,beijing 100081,china

The geomagnetic fields,which play important roles in the ionospheric dynamo,can greatly affect the global distribution of ionospheric electric fields,currents and other ionospheric electrodynamics *** the study of ionospheric electrodynamics phenomena,such as the longitudinal variations of ionospheric electric fields,the non-dipolar component of the geomagnetic fields must be taken into *** this paper,we deduce a theoretical electric field model for ionospheric dynamo at mid- and low-latitude which adopt a modified magnetic apex coordinates *** the new electric field model,the geomagnetic fields can be calculated from either the IGRF model or the dipole field model, and the neutral winds and conductivities are calculated based on empirical *** the dynamo equation for the electric potential is finally solved in terms of the line-by-line iteration method,and the ionospheric electric fields and currents are derived from the calculated *** model can reproduce the main features of the ionospheric electrodynamics processes,so it will be a useful tool for the investigation of the upper atmosphere and ionosphere.

关键词： ionospheric dynamo ionospheric electric fields APEX coordinates

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Mapping the MLT tides from meteor radar observations of a meridional chain

Mapping the MLT tides from meteor radar observations of a me...

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中国地球物理学会第二十七届年会

作者： You yu~(1,2) weixing wan~(1*) Baiqi Ning~1 libo liu~1 Zhengui wang~(1,2) 1.beijing National observatory of space environment,institute of geology and geophysics, chinese academy of sciences,beijing,10029 2.Graduate University of chinese academy of sciences,beijing 100049, china

＜正＞Mesosphere and low thermosphere（MLT）,as an important coupling region in upper atmosphere,plays important roles in the dynamical processes as well as the transportation of energy and *** decades, to understand this complicated dynamical region,extensive wind observations have been conducted from the ground-based and space-based *** of observations have revealed a wealth of information on atmospheric tides,but they suffer from lack of global structure and local time coverage *** article proposes a technique to map the tidal winds in mesosphere and lower thermosphere（MLT） region from the observation of the meteor radar chain located along the 120°E meridional circle in china[*** et al,2004]. The observed zonal and meridional winds were first decomposed into mean,diurnal,semidiurnal and terdiurnal tidal components in the altitude range 82～94 km for stations at different latitudes（from 18.3°N to 40.3°N） in the

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Modeling the global ionospheric total electron content with empirical orthogonal function analysis

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Science china(Technological sciences) 2012年第5期55卷 1161-1168页

作者： wan weixing DING Feng ren zhipeng ZHANG ManLian liu libo NING BaiQi beijing National observatory of space environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China

In the present work we model the global ionospheric total electron content (TEC) with the analysis of empirical orthogonal functions (EOF). The obtained statistical eigen modes, which makeup the modeled TEC, consist of two factors: the eigen vectors mapping TEC patterns at latitude and longitude (or local time LT), and the corresponding coefficients displaying the TEC variations in different time scales, i.e., the solar cycle, the yearly (annual and semiannual) and the diurnal universal time variations. It is found that the EOF analysis can separate the TEC variations into chief processes and the first two modes illustrate the most of the ionospheric climate properties. The first mode contains both the semiannual component which shows the semiannual ionospheric anomaly and the annual component which shows the annual or non-seasonal ionospheric anomaly. The second mode contains mainly the annual component and shows the normal seasonal ionospheric variation at most latitudes and local time sectors. The annual component in the second mode also manifests seasonal anomaly of the ionosphere at higher mid-latitudes around noontime. It is concluded that the EOF analysis, as a statistical eigen mode method, is resultful in analyzing the ionospheric climatology hence can be used to construct the empirical model for the ionospheric climatology.

关键词： ionospheric modeling total electron content empirical orthogonal functions

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Global characteristics of occurrence of an additional layer in the ionosphere observed by COSMIC/FORMOSAT-3

Global characteristics of occurrence of an additional layer ...

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中国科学院地质与地球物理研究所第11届（2011年度）学术年会

作者： Biqiang Zhao,weixing wan,Xinan yue,libo liu,zhipeng ren,Maosheng He, and Jing liu 1 beijing National observatory of space environment,institute of geology and geophysics,chinese academy of sciences,beijing,china. 2 State Key Laboratory of space Weather,chinese academy of sciences,beijing,china. 3 COSMIC Program Office,University Corporation for Atmospheric Research,Boulder,Colorado,USA. 4 Graduate University of chinese academy of sciences,beijing,china.

[1]Global observations of electron density profile(EDP) from the COSMIC/FORMOSAT-3 satellites were used to investigate,for the first time,the additional stratification of the F2 layer over the equatorial ionosphere on a global scale,which is called F3 *** F3 layer in EDP was recognized through the altitude differential profile featured by two maxima existing from 220 km to the peak height of the electron *** were ,400 cases of F3 layer selected out of 48,000 occultation events at low and equatorial areas during the period of April 2006-September *** results show that the highest occurrence of F3 layer appears at dip latitude 7-8°/ -7～-8°for Northern/Southern Hemisphere and is more pronounced during summer months at 10:00-14:00 LT. The occurrence also has a clear longitude dependence during boreal summer,with relatively higher occurrence at -80～-100°,-20～20°,80～120°and -160～-170°longitudes, that is possibly associated with the wavenumber-3 diurnal tide(DE3).The results support the principle of the F3 layer proposed by Balan et al.(1998),which in turn validate the accuracy of the retrieval of the COSMIC EDP data.

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Statistics of GPS ionospheric scintillation and irregularities over polar regions at solar minimum

Statistics of GPS ionospheric scintillation and irregulariti...

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中国科学院地质与地球物理研究所第十届(2010年度)学术年会

作者： Guozhu Li·Baiqi Ning·zhipeng ren·Lianhuan Hu beijing National observatory of space environment, institute of geology and geophysics, chinese academy of sciences,beijing,china

A statistical study of the occurrence characteristic of GPS ionospheric scintillation and irregularity in the polar latitude is *** measurements were made at Ny-Alesund,Svalbard[78.9°N,11.9°E;75.8°N corrected geomagnetic latitude(CGMLat)]and Larsemann Hills,East Antarctica(69.4°S,76.4°E;74.6°S CGMLat) during *** is found that the GPS phase scintillation and irregularity activity mainly takes place in the months 10,11 and 12 at Ny-Alesund,and in the months 5, 6 at Larsemann *** seasonal pattern of phase scintillation with respect to the station indicates that the GPS phase scintillation occurrence is a local winter phenomenon, which shows consistent results with past studies of 250 MHz satellite beacon *** occurrence rates of GPS amplitude scintillation at the two stations are below 1%.A comparison with the interplanetary magnetic field(IMF) B and B components shows that the phase scintillation occurrence level is higher during the period from later afternoon to sunset(16-19 h) at Ny-Alesund, and from sunset to pre-midnight(18-23 h) at Larsemann Hills for negative IMF *** findings seem to indicate that the dependence of scintillation and irregularity occurrence on geomagnetic activity appears to be associated ith the magnetic local time(MLT).

关键词： GPS Ionospheric scintillation Polar latitude irregularity IMF

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