中纬电离层f_0F_2的暴时变化  

STORM TIME VARIATION OF f_0F_2 AT MID-LATITUDEIONOSPHERE

作　　者：沈长寿[1] 资民筠[2] 高玉芬[3] 吴健[4] 索玉成[4] 

机构地区：[1]北京大学地球物理系,北京100871 [2]中国艺术研究院,北京100009 [3]中国地震局地球物理研究所,北京100081 [4]电子工业部电波传播研究所,新乡453003

出　　处：《地球物理学报》1999年第2期154-162,共9页Chinese Journal of Geophysics

基　　金：国家自然科学基金!49674245

摘　　要：用近５０个中纬（磁纬在±２０°-５０°之间）电离层垂测站的ｆ０Ｆ２资料，分析与磁暴相伴的电离层暴事例表明：地磁Ｄｓｔ指数与中纬电离层ｆ０Ｆ２暴时变化Ｄｓ（ｆ０Ｆ２　）有大致相似的发展趋势。但用时序叠加法求得的强度不同、发展过程和持续时间不同的多次电离层暴ｆ０Ｆ２变化的平均值，其物理意义是很不明确的。暴时ｆ０Ｆ２变化的地方时分布Ｄｓ（ｆ０Ｆ２）中，一般说以全日周期扰动幅度（Ａ１）为最强，但电离层负暴峰值后常出现半日周期扰动（Ａ２）的增强，且有时Ａ２＞Ａ１．Ａ１的涨落趋势与Ｄｓｔ（ｆ０Ｆ２）相似，但特强磁暴时，Ａ１值有可能反而变小．以Ａ１ｓｉｎ（ω　ｔ＋　１）表示的全日周期扰动中，初位相１值随暴时的发展而变小表明，扰动分布形态是基本上随地球一起转动的。Using data observed simultaneously from about 50 stations distributed worldwidearound mid-latitude zone, the case analyses of ionospheric disturbances accompaniedby geomagnetic storms indicate that the variation of the geomagnetic Dst index andthat of the storm time variation of mean f0F2 (average departure of f0F2 frommonthly median value), Dst(f0F2), obtained by Fourier expansion have similar tendency.However, the average variation, produced by the superposed epoch analysis using dataduring periods of ionospheric storms with different intensities and storm time lengths,has no real physical meaning. Generally speaking, the amplitude of the diurnalvariation.(A1) deduced from the Fourier analysis of f0F2 is the strongest one. Thereare cases, however, with large A2(the amplitude of the senu-diurnal variation), whichcan even be larger than A1. Usually, the fluctiiation of A1 is similar to that of theDst(fOF2), but it becomes small when a storm is very strong. The phase angle 1 ofthe diurnal variation, showed as A1Sin( t+ 1), decreases with the developing of thestorm time. This indicates that the disturbance pattern some how varies to follow therotation of the earth.

关 键 词：磁暴 电离层暴 暴时变化 中纬电离层 

分 类 号：P352.4[天文地球—空间物理学]