南极地区地磁扰日变化S_D场特征

利用南极地磁资料研究了地磁扰日变化ＳＤ场特征。１）ＳＤ场变化不如Ｓｑ场变化规则,无明显的昼夜差异;太阳活动高年（１９９１年）比下降年（１９９４年）ＳＤ场变化更强烈。２）极隙区中山站ＳＤ场变幅比亚极光区长城站和北半球低纬区北京台的ＳＤ场变幅大１０倍以上。３）中山站Ｓ０Ｄ（Ｈ）变化呈“正弦波”形态,与长城站和北京台Ｓ０Ｄ（Ｈ）变化形态相反。４）中山站Ｓ０Ｄ等效电流矢量在早晨－下午（０２～１５ｈ）矢量方向为反时针西向,下午－夜间（１５～０２ｈ）矢量方向为顺时针东向,这是由极区东向、西向电射流和极区电流涡旋所引起;长城站与北京台Ｓ０Ｄ等效电流矢量很小,这是由极区东向和西向电射流的影响所致。

GEOMAGNETIC DISTURBED DAILY VARIATION S D FIELD IN ANTARCTICA

Geomagnetic data of Antarctic region were used to study the characteristics of the disturbed daily variation (S D) of geomagnetic field. 1) Unlike S q field,S D field variation is irregular and doesn't have obvious differrence inthe daytime and nighttime. The S D variation is more intense in the solar maximum year(1991) than in the decreasing phase of solar cycle(1994) at Zhongshan Station. 2)Amplitude of the S D field at Zhongshan Station in polar cusp is ten times as large as that at Great Wall Station in sub auroral region and that at Beijing Observatory in low latitude of the north hemisphere. The S D field consist of the periodical disturbed daily variation (S 0 D) and superposed irregular intense disturbance (S d D). 3) The morphology of S 0 D(H) is a "Sin" pattern at Zhongshan Station,which is opposed to that at Great Wall Station and Beijing Observatory. 4) The equivalent current vectors of S 0 D variation at Zhongshan Station are clockwise westward in the morring afternoon (02-15h) and counter clockwise eastward in the afternoon-night(15-02h). Therefore,the S D field is cuased by the current system consisting of eastward and westward electroject current and the current vortex in the cap region at Zhongshan Station.The equivalent current vectors of S 0 D variation are very small at Great Wall Station and Beijing Observatory, so that S D field is affected by eastward and westward electroject current in the polar region.