北京地区Pi2脉动和地磁AE指数的关系  

RELATIONSHIP BETWEEN Pi2 IN BEIJING AND AE INDEXES

作　　者：曹晋滨[1] 王德驹[1] 赵华[1] 周国成[1] 

机构地区：[1]中国科学院空间科学与应用研究中心空间天气开放实验室,北京100080

出　　处：《地球物理学报》2004年第6期949-953,共5页Chinese Journal of Geophysics

基　　金：国家杰出青年基金项目资助 ( 4 0 0 2 5 413 )

摘　　要：分析了北京地区 1998年 1月 1日至 3月 2 6日和 4月 2 4日至 6月 13日共 136天记录的Pi2脉动事件特性 ,并与同时期亚暴AE指数进行了对比 .结果发现 ,在北京地区越靠近日侧 ,观测到的Pi2脉动事件越少 ,幅度也越小 .并不是每次亚暴都能激发空腔振荡模 ,亚暴强度的增加也并不代表空腔振荡模产生概率的增加 .随着亚暴AE指数的增大 ,Pi2脉动的平均幅度基本上也在增大 .但也有例外 ,可能是由于北京观测地点距离亚暴电流楔位置较远造成的 .北京地区的Pi2脉动可以发生于亚暴的整个过程中 ,从AE指数开始增长期间 (亚暴增长相 ) ,一直到亚暴AE指数恢复正常 (亚暴膨胀相后期 ) .某些亚暴没有对应着Pi2脉动事件 ,其AE指数从小于 2 0 0nT一直到80 0nT以上 .从观测数据来看 ,北京地区虽然纬度分区在低纬区域 ,但其Pi2脉动的特性与中纬Pi2特性更为靠近 .所以不宜用北京地区Pi2来预报亚暴 。We analyze the characteristics of Pi2s in Beijing from January 1 to March 26 in 1998 and from April 24 to June 13 in 1998, and compare them with AE indexes. In Beijing near the noon time, the occurrence rate of Pi2 is less and the amplitudes of Pi2s smaller. Not all substorms can excite the cavity oscillation modes. The amplitudes of Pi2 usually increase with the growth of AE index. However there remain some exceptions which may be due to the fact that Beijing is sometimes very far from the substorm current wedge. Pi2s in Beijing are throughout the whole substorm stages. However for some substorms, no Pi2 is found in Beijing. The AE indexes of these substorms range from 200 nT to 800 nT. Although Beijing is classified as a low lattitude region, the characteristics of Pi2s in Beijing are more analogous to that of the Pi2s in middle latitude regions. So it is not very credible to use the Pi2s in Beijing to predict and monitor substorms.

关 键 词：Pi2脉动 磁层亚暴 AE指数 北京地区 

分 类 号：P353[天文地球—空间物理学]