地磁静日期内北半球电离层N_mF_2的结构分布  

STRUCTURE DISTRIBUTION OF N_mF_2 IN THE IONOSPHERE OF THE NORTHERN HEMISPHERE DURING A GEOMAGNETICALL QUIET PERIOD

作　　者：沈长寿[1] 资民筠[1] 王劲松[1] 徐寄遥[2] 

机构地区：[1]北京大学地球与空间科学学院,北京100871 [2]中国科学院空间天气开放实验室,北京100080

出　　处：《地球物理学报》2003年第6期731-735,共5页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目 ( 4 9990 45 5和 40 2 2 5 0 11);973项目 (G2 0 0 0 0 7840 7)

摘　　要：用北半球陆地上 4 8个地面电离层垂测站资料 ,以及国际参考电离层IRI 90模式 ,考察 1985年 1月 6～ 7日F2 层电子密度最大值日变化的纬度剖面和经度效应 .结果表明 ,在亚洲地区的 2 0°N～ 30°N内 ,F2 层赤道异常“喷泉效应”产生的NmF2 “北驼峰”最高 ,其最大值出现在中午 ,或稍迟时间 .30°N～ 5 0°N区域内 ,NmF2 的白天峰值幅度逐渐下降 ,峰值时间移至午前约 10 :0 0LT .更高纬度 (5 0°N～ 6 2°N )台站上 ,中午前后NmF2 出现双峰 ,傍晚有谷值 ,夜间又再次抬升 .欧、美地区的低纬台站很少 ,但借助IRI 90模式分析可发现 ,在 2 70°E经圈上 ,“喷泉效应”造成的“北驼峰”幅度最小 ,而且随纬度增大时 ,NmF2 白天幅度下降也不明显 ,即纬度剖面的经度效应非常显著 .对中国、日本地区台站资料的小范围经度差异分析表明 ,在驼峰区的 90°E～ 14 0°E内 ,各站NmF2 无明显差别 ;但在中纬地区 30°N～ 5 0°N内 ,中国西部上空NmF2 白天变化幅度较大 ,且较为陡直 ,而中国东部和日本台站上空则相对平缓 .Using the data from 48 ionosondes in the Northern Hemisphere and the model of IRI-90, the latitude profiles of variations of N mF 2 on Jan. 7, 1985 at sunspot minimum are investigated. The results show that for the F 2 layer equatorial anomaly the “fountain effect” is strongest at Asia region and the “northern crest” at (20°N～30°N) is highest with a maximum value of N mF 2 at noon, or a bit later. At the range of 30°N～50°N the F 2 peaks decrease gradually and the peak times move to about 10:00 LT, while in the high latitude region (50°N～62°N) two peaks appear around noon, followed by a valley at dusk and the peak values increase again during the night. There are very few ionosondes at low latitude in the European and American regions. Nevertheless, using the model of IRI-90, it can be still found that the northern “crest” produced by the “fountain effect” is weakest at longitude 270°E. The decrease of daytime F 2 peaks at higher latitude is not evident in these regions. It means that the longitude change of latitude profiles of N mF 2 diurnal variations is obvious. On the other hand, analysis of data measured by ionosondes in China and Japan (in a narrower range of longitude) shows that N mF 2 diurnal variations in the region of 90°E～140°E has no great longitude difference, or so-called longitude effect, at “crest” region (20°N～30°N). However, at middle latitude (30°N～50°N) the variation amplitudes of N mF 2 are larger and steeper in the west of China than that in the east of China and Japan.

关 键 词：地磁静日 电离层NmF2 结构分布 纬度剖面 经度效应 

分 类 号：P352[天文地球—空间物理学]