Sq电流系午前午后不对称性现象的来源  

The origin of the prenoon-postnoon asymmetry for Sq current system

作　　者：赵旭东[1] 杜爱民[1] 徐文耀[1] 洪明华[1] 刘立波[1] 魏勇[1] 王程功[1] 

机构地区：[1]中国科学院地质与地球物理研究所

出　　处：《地球物理学报》2008年第3期643-649,共7页Chinese Journal of Geophysics

基　　金：国家自然科学基金(40772086,40536029);973计划(2006CB806305);地震行业科研专项(200708043)资助

摘　　要：太阳静日变化Sq是地球变化磁场的基本组成部分,Sq的特征反映电离层的电性质和高层大气的潮汐特性.研究Sq的变化特性,能够加深对电离层-热层耦合的认识.准确分离出Sq,为计算地磁指数(如Dst、Kp和AE等)以及空间天气的准确预报提供必要信息.本文利用地磁观测数据,重点分析了北半球Sq形态及其午前午后不对称现象、Sq日变幅的变化特征、不同纬度地区日变幅与太阳天顶角的相关性的差异.研究表明低纬电流系和高纬电流系是引起Sq形态变化的重要来源,也是各种不对称性的主要起因.The solar quiet variation （Sq） is one typical kind of the variable magnetic field of the Earth. The feature of Sq reflects the structure of electricity and high altitude atmosphere tide in ionosphere. The variation of Sq takes an important role of understanding the process in coupling of ionosphere-thermosphere. It is necessary to separate the Sq correctly from the geomagnetic field in order to estimate the geomagnetic indices （such as the Dst, Kp and AE indices） and forecast the level of geomagnetic activity. In this paper, the geomagnetic field data observed by ground-based observatories are used to analysis the configuration of Sq, the prenoon-postnoon asymmetry, and the daily variations of Sq depended on the latitude and solar zenith. The results indicate that the asymmetry of Sq is resulted from interaction between the current systems in low and high latitude regions.

关 键 词：Sq电流系 Sq逐日变化 DP2电流系 Sq^p电流系 

分 类 号：P353[天文地球—空间物理学]