Statistical Study on the Response of TEC to Geomagnetic Stormsormalsize
-
摘要:
磁暴期间白天电离层总电子含量（TEC）大幅度扰动.TEC扰动与磁暴发生时的世界时（UT）有关.利用7年的数据对TEC对磁暴的响应进行统计研究.结果显示，磁暴期间白天TEC增大明显，且在午后TEC的增大比例有一个高峰.在18：00UT-04：00UT，南美地区与其他地区相比TEC增长较大，这可能与白天的光照有关.为了研究TEC变化与磁暴的关系，结合同样时间段的Dst指数，把TEC数据分为磁暴日（Dst<-100nT）和平静日（Dst>-50nT）.研究发现，将TEC前移2h，低纬日侧地区TEC增大值随着世界时的变化与Dst变化的负相关性较好，相关系数为-0.75.在中纬度地区，将TEC扰动前移1h，相关系数为-0.61.这可能是行进式大气扰动携带着赤道向的子午风，由极区向低纬传播引起.可以认为，TEC的变化可能是由磁暴引起的.在高纬地区，TEC增大值随着世界时的变化与Dst变化的相关性较差.这可能是由于太阳高度角较低，光辐射通量较小，导致电子密度的增加不明显.
Abstract:The ionospheric Total Electron Content (TEC) in the daytime is often greatly disturbed during geomagnetic storms. Recent reports suggest that the disturbance of TEC depends on the Universal Time (UT) of storm onset. By using the TEC global maps over a 7-year period produced by the Jet Propulsion Laboratory, the response of TEC to geomagnetic storms is investigated. The analysis confirms that TEC increases obviously in day time, and extends across the noon sector with an afternoon peak. In 18:00UT-04:00 UT, American sector continues to exhibit a storm time, which TEC enhancement is higher than those observed in the other sector. It is possibly related to the sunlight in day time. In order to study the relation between TEC enhancement and the corresponding magnetic storms, the TEC data are divided into quiet (Dst>-50nT) and active (Dst<-100nT) sets using Dst index. The results show that the TEC variation at low latitudes has negative relation to Dst as the TEC variation is moved forward about 2 hours. The relation coefficient is -0.75. The TEC variation at middle latitudes has negative relation to Dst with a coefficient of -0.61, as it is moved forward about 1 hour. The reason may be that the travelling atmosphere disturbance carries the equatorial meridional wind, and propagates from polar region to low latitude. It can be concluded that the TEC variation is induced by geomagnetic storms. However, the correlation is poor at high latitudes. It is possibly because of the complexity of sectors at high latitudes.
-
Key words:
- Geomagnetic storms /
- TEC disturbance /
- Dst index /
- Correlation
-
[1] IMMEL T J, CROWLEY G, CRAVEN J D, et al. Dayside enhancements of thermospheric O/N2 following magnetic storm onset[J]. J. Geophys. Res., 2001, 106 (A8):15471-15488 [2] PRÖLSS G W. Ionospheric storms at mid-latitude:a short review[M]//Midlatitude Ionospheric Dynamics and Disturbances. Washington DC:AGU, 2008:9-24 [3] LANZEROTTI L J, COGGER L L, MENDILLO M. Latitude dependence of ionosphere total electron content:observations during sudden commencement storms[J]. J. Geophys. Res., 1975, 80 (10):1287-1306 [4] FOSTER J C. Storm-time plasma transport at middle and high latitudes[J]. J. Geophys. Res., 1993, 98 (A2):1675-1689 [5] JONES K L, RISHBETH H. The origin of storm increases of mid-latitude F-layer electron concentration[J]. J. Atmos. Terr. Phys., 1971, 33 (3):391-401 [6] ANDERSON D N. Modeling the midlatitude F-region ionospheric storm using east-west drift and a meridional wind[J]. Planet. Space Sci., 1976, 24 (1):69-77 [7] HUNSUCKER R D, HARGREAVES J K. The High-latitude Ionosphere and its Effects on Radio Propagation[M]. Cambridge:Cambridge University Press, 2002 [8] ROBLE R G. Studies in Geophysics:the Upper Atmosphere and Magnetosphere[M]. Washington D C:National Academy of Sciences, 1977 [9] FULLER-ROWELL T J, REES D, RISHBETH H, et al. Modelling of composition changes during F-region storms:a reassessment[J]. J. Atmos. Terr. Phys., 1991, 53 (6/7):541-550 [10] HUBA J D, JOYCE G, SAZYKIN S, et al. Simulation study of penetration electric field effects on the low-to mid-latitude ionosphere[J]. Geophys. Res. Lett., 2005, 32 (23):L23101 [11] MANNUCCI A J, WILSON B D, YUANDN, et al. A global mapping technique for GPS-derived ionospheric total electron content measurements[J]. Radio Sci., 1998, 33 (3):565-582 [12] KINTNER P M, LEDVINA B, DE PAULAE, et al. The advantages of cheap, connected, and plentiful GNSS observations[C]//American Geophysical Union, Fall Meeting 2003. Washington, DC:AGU, 2003 [13] XIA Chunliang, WAN Weixing, YUAN Hong, et al. Analysis of the intense magneticstorm of July, 2000 and of October, 2003 using the technique for nowcasting of GPS TEC data[J]. Chin. J. Space Sci., 2005, 25 (4):259-266(夏淳亮, 万卫星, 袁洪, 等. 2000年7月和2003年10月大磁暴期间东亚地区中低纬电离层的GPS TEC的响应研究[J].空间科学学报, 2005, 25 (4):259-266) [14] JAKOWSKI N, STANKOV S M, SCHLUETER S, et al. On developing a new ionospheric perturbation index for space weather operations[J]. Adv. Space Res., 2006, 38 (11):2596-2600 [15] MENDILLO M. Storms in the ionosphere:patterns and processes for total electron content[J]. Rev. Geophys., 2006, 44 (4):RG4001 [16] MENDILLO M, KLOBUCHAR J A. Total electron content:synthesis of past storm studies and needed future work[J]. Radio Sci., 2006, 41 (5):RS5S02 [17] XU Jisheng, ZHU Jie, CHENG Guanghui. GPS observations of ionospheric effects of the major storm of Nov.7-10, 2004[J]. Chin. J. Geophys., 2006, 49 (4):950-956 [18] ERICKSON P J, GONCHARENKO L P, NICOLLS M J, et al. Dynamics of North American sector ionospheric and thermospheric response during the November 2004 superstorm[J]. J. Atmos. Sol-Terr. Phys., 2009, 72 (4):292-301. DOI: 10.1016/j.jastp.2009.04.001 [19] BALAN N, SHIOKAWA K, OTSUKA Y, et al. A physical mechanism of positive ionospheric storms at low latitudes and midlatitudes[J]. J. Geophys. Res., 2010, 115 (A2):A02304. DOI: 10.1029/2009JA014515 [20] DENG Zhongxin, LIU Ruiyuan, ZHEN Weimin, et al. Study on the ionospheric TEC storms over China[J]. Chin. J. Geophys., 2012, 55 (7):2177-2184 [21] BUONSANTO M J. Ionospheric storms review[J]. Space Sci. Rev., 1999, 88 (3/4):563-601 [22] IMMEL T J, MANNUCCI A J. Ionospheric redistribution during geomagnetic storms[J]. J. Geophys. Res., 2013, 118 (12):7928-7939 -
点击查看大图
计量
- 文章访问数: 1387
- HTML全文浏览量: 63
- PDF下载量: 758
- 被引次数: 0
下载:
