Longitudinal Variations of Total Ion Density in the Topside Ionosphere
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摘要: 利用DMSP F13卫星1996-2005年共10年的观测数据,研究地磁中低纬地区黄昏时段(18:00 LT)顶部电离层总离子密度经度变化的季节、地磁纬度和太阳活动变化特征.结果表明总的经度变化在低纬地区与中纬地区具有明显不同特征.不同经度结构的季节变化均以年变化为主,但纬度分布具有明显差异.一波结构主要集中在中纬地区,且南半球明显强于北半球;二波结构南北半球不对称性非常明显;三波结构和四波结构均为低纬地区明显强于中纬地区.通过分析不同波结构对总经度变化的贡献发现,一波结构在南半球中纬地区贡献最大,二波结构在12月前后的15°N附近贡献较大,三波结构和四波结构仅在低纬地区有较强贡献.在不同太阳活动条件下,不同波结构的贡献率有明显变化.Abstract: Based on DMSP F13 Satellite observations from 1996 to 2005,the seasonal,geomagnetic latitude and solar cycle variations of the total ion density in the sunset topside ionosphere at middle and low latitudes are investigated.Results indicate that the longitudinal variation of the total ion density is obviously different between the low latitudes and the middle latitudes.Annual components of longitude structures seasonal variations are dominated at most latitudes,and these longitudinal structures show latitudinal dependence:relative strength of mid-latitude wavenumber-one structure in the southern hemisphere are much greater than that in the northern hemisphere;the hemispheric asymmetry of wavenumber-two structure is remarkable at middle and low latitudes;wavenumberthree structure and wavenumber-four structure are both much more dominant in the low latitudes than in the middle latitudes.Besides,contributions of different wave structures to total ion density are also examined:wavenumber-one structure is dominant at southern middle latitudes,and in the northern winter,the region around 15°N is mainly controlled by wavenumber-two structure. Wavenumber-three structure and wavenumber-four structure only prevail at low latitudes.Contributions of different wave structures change with solar cycle variations.
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Key words:
- Longitudinal variation /
- Seasonal variation /
- Topside ionosphere
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[1] XIONG Nianlu, TANG Cunchen, LI Xingjian. Introduction of Ionospheric Physics[M]. Wuhan:Wuhan University Publishing Company, 1997(熊年禄,唐存琛,李行健.电力层物理概论[M].武汉:武汉大学出版社, 1997) [2] BALAN N, OTSUKA Y, FUKAO S, et al. Annual variations of the ionosphere:a review based on MU radar observations[J]. Adv. Space Res., 2000, 25(1):153-162 [3] PEDATELLA N M, FORBES J M, MAUTE A, et al. Longitudinal variations in the F region ionosphere and the topside ionosphere-plasmasphere:observations and model simulations[J]. J. Geophys. Res., 2011, 116, A12309. DOI: 10.1029/2011JA016600 [4] SU Y Z, BAILEY G J, FUKAO S. Altitude dependencies in the solar activity variations of the ionospheric electron density[J]. J. Geophys. Res., 1999, 104(A7):14879-14891 [5] PARK S M, KIM H, MIN S, et al. Effects of solar activity variations on the low latitude topside nighttime ionosphere[J]. Adv. Space Res., 2008, 42:626-633 [6] SAGAWA E, IMMEL T J, FREY H U, et al. Longitudinal structure of the equatorial anomaly in the nighttime ionosphere observed by IMAGE/FUV[J]. J. Geophys. Res., 2005, 110, A11302. DOI: 10.1029/2004JA010848 [7] LIN C H, HSIAO C C, LIU J Y, et al. Longitudinal structure of the equatorial ionosphere:Time evolution of the four-peaked EIA structure[J]. J. Geophys. Res., 112, A12305. DOI: 10.1029/2007JA012455 [8] WAN W, LIU L, PI X, et al. Wavenumber-4 patterns of the total electron content over the low latitude ionosphere[J]. Geophys. Res. Lett., 2008, 35, L12104. DOI: 10.1029/2008GL033755 [9] WAN W, XIONG J, REN Z, et al. Correlation between the ionospheric WN4 signature and the upper atmospheric DE3 tide[J]. J. Geophys. Res., 2010, 115, A11303. DOI: 10.1029/2010JA015527. [10] REN Zhipeng, WAN Weixing, LIU Libo, et al. Longitudinal variations of electron temperature and total ion density in the sunset equatorial topside ionosphere[J]. Geophys. Res. Lett., 2008, 35, L05108. DOI: 10.1029/2007GL032998 [11] SCHERLIESS L, THOMPSON D C, SCHUNK R W. Longitudinal variability of low-latitude total electron content:tidal influences[J]. J. Geophys. Res., 113, A01311.DOI: 10.1029/2007JA012480 [12] ENGLAND S L, MAUS S, IMMEL T J, et al. Longitudinal variation of the E-region electric fields caused by atmospheric tides[J]. Geophys. Res. Lett., 2006, 33, L21105. DOI: 10.1029/2006GL027465 [13] LÜHR H, ROTHER M, HÄUSLER K, et al. The influence of nonmigrating tides on the longitudinal variation of the equatorial electrojet[J]. J. Geophys. Res., 113, A08313. DOI: 10.1029/2008JA013064 [14] REN Zhipeng, WAN Weixing, LIU Libo, et al. Intraannual variation of wave number 4 structure of vertical E×B drifts in the equatorial ionosphere seen from ROCSAT-1[J]. J. Geophys. Res., 114, A05308. DOI: 10.1029/2009JA014060 [15] HARTMAN W, HEELIS R. Longitudinal variations in the equatorial vertical drift in the topside ionosphere[J]. J. Geophys. Res., 112, A03305. DOI: 10.1029/2006JA011773 [16] KIL H, OH S J, KELLEY M C, et al. Longitudinal structure of the vertical E×B and ion density seen from ROCSAT-1[J]. Geophys. Res. Lett., 34, L14110. DOI:10. 1029/2007GL030018 [17] KIL H, TALAAT E R, OH S J, et al. Wave structures of the plasma density and vertical E×B drift in lowlatitude F region[J]. J. Geophys. Res., 113, A09312. DOI: 10.1029/2008JA013106 [18] FEJER B G, JENSEN J W, SU S Y. Quiet time equatorial F region vertical plasma drift model derived from ROCSAT-1 observations[J]. J. Geophys. Res., 113, A05304. DOI: 10.1029/2007JA012801 [19] REN Zhipeng, WAN Weixing, XIONG Jiangang, et al. Simulated wave number 4 structure in equatorial F-region vertical plasma drifts[J]. J. Geophys. Res., 115, A05301. DOI: 10.1029/2009JA014746 [20] LIU L, WAN W, YUE X, et al. Topside ionospheric scale heights retrieved from constellation observing system for meteorology, ionosphere, and climate radio occultation measurements[J]. J. Geophys. Res., 113, A10304. DOI: 10.1029/2008JA013490 [21] WAN W, REN Z, DING F, et al. A simulation study for the couplings between DE3 tide and longitudinal WN4 structure in the thermosphere and ionosphere[J]. J. Atmos. Terr. Phys., 2012, 90:52-60 [22] IMMEL T J, SAGAWA E, ENGLAND S L, et al. Control of equatorial ionospheric morphology by atmospheric tides[J]. Geophys. Res. Lett., 2006, 33, L15108. DOI:10. 1029/2006GL026161 [23] ENGLAND S L, ZHANG XIAOLI, IMMEL T J, et al. The effect of non-migrating tides on the morphology of the equatorial ionospheric anomaly:seasonal variability[J]. Earth Planets Space, 2009, 61:493-503 [24] ENGLAND, S L, IMMEL T J, HUBA J D, et al. Modeling of multiple effects of atmospheric tides on the ionosphere:an examination of possible coupling mechanisms responsible for the longitudinal structure of the equatorial ionosphere[J]. J. Geophys. Res., 2012, 115, A05308. DOI: 10.1029/2009JA014894 [25] WU Q, SOLOMON S C, KUO Y H, et al. Spectral analysis of ionospheric electron density and mesospheric neutral wind diurnal nonmigrating tides observed by COSMIC and TIMED satellites[J]. Geophys. Res. Lett., 2009, 36, L14102. DOI: 10.1029/2009GL038933 [26] FANG T W, KIL H, MILLWARD G, et al. Causal link of the wave-4 structures in plasma density and vertical plasma drift in the low-latitude ionosphere[J]. J. Geophys. Res., 2009, 114, A10315. DOI: 10.1029/2009JA014460 [27] HE Maosheng, LIU Libo, WAN Weixing, et al. Strong evidence for couplings between the ionospheric wave-4 structure and atmospheric tides[J]. Geophys. Res. Lett., 2011, 38, L14101. DOI: 10.1029/2011GL047855 [28] JIN H, MIYOSHI Y, FUJIWARA H, et al. Electrodynamics of the formation of ionospheric wavenumber4 longitudinal structure[J]. J. Geophys. Res., 2008, 113, A09307. DOI: 10.1029/2008JA013301 [29] HAGAN M E, MAUTE A, ROBLE R G, et al. Connections between deep tropical clouds and the Earth's ionosphere[J]. Geophys. Res. Lett., 2007, 34, L20109. DOI:10. 1029/2007GL030142 [30] BANKOV L, HEELIS R, PARROT M, et al. 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[J]. Ann. Geophys., 2009, 27:2893-2902 [31] WEST K H, HEELIS R A. Longitude variations in ion composition in the morning and evening topside equatorial ionosphere near solar minimum[J]. J. Geophys. Res., 1996, 101(A4):7951-7960 [32] RICHMOND A D. The Upper Mesosphere and Lower Thermosphere:A Review of Experiment and Theory[M]. Washington D C:American Geophysical Union, 1995 [33] KIL H, PAXTON L J, LEE W K, et al. Is DE2 the source of the ionospheric wavenumber 3 longitudinal structure[J]. J. Geophys. Res., 2010, 115, A11319. DOI: 10.1029/2010JA015979 [34] FEJER B G, PAULA DE E R, GONZALEZ S A, et al. Average vertical and zonal F region plasma drifts over JICAMARCA[J]. J. Geophys. Res., 1991, 96(A8):13901-13906
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