地球物理学进展
地毬物理學進展
지구물이학진전
PROGRESS IN GEOPHYSICS
2009年
6期
1951-1957
,共7页
张晓芳%符养%严卫%李就
張曉芳%符養%嚴衛%李就
장효방%부양%엄위%리취
高能电子%太阳风%地磁活动%小波分析%交叉小波分析
高能電子%太暘風%地磁活動%小波分析%交扠小波分析
고능전자%태양풍%지자활동%소파분석%교차소파분석
high-energy electron%solar wind%magnetic activity%wavelet analysis%cross wavelet analysis
结合小波分析及交叉小波分析方法,研究了地球同步轨道高能电子动态变化的多时间尺度结构,分析了电子通量在不同周期随着太阳风速、地磁指数D_(st)变化的具体特点.结果发现:(1)电子通量的长期变化受控于太阳风速,在太阳活动低值年,电子通量值高,具有明显的13.4天,27.4天及187天周期;交叉小波分析表明,电子通量的13.4天及27.4天周期受太阳风速周期变化信号的影响,187天周期变化受D_(st)指数周期变化信号的影响.(2)电子通量半年变化主要归因于太阳风的驱动作用,在每年的第100天及270左右达到两次峰值,峰值大小不对称,与D_(st)指数的谷值大小呈反比.(3)由于冕洞形成过程中的太阳风高速流影响,电子通量具有13.4及27.4天的周期,峰值水平受控于太阳风速结构.
結閤小波分析及交扠小波分析方法,研究瞭地毬同步軌道高能電子動態變化的多時間呎度結構,分析瞭電子通量在不同週期隨著太暘風速、地磁指數D_(st)變化的具體特點.結果髮現:(1)電子通量的長期變化受控于太暘風速,在太暘活動低值年,電子通量值高,具有明顯的13.4天,27.4天及187天週期;交扠小波分析錶明,電子通量的13.4天及27.4天週期受太暘風速週期變化信號的影響,187天週期變化受D_(st)指數週期變化信號的影響.(2)電子通量半年變化主要歸因于太暘風的驅動作用,在每年的第100天及270左右達到兩次峰值,峰值大小不對稱,與D_(st)指數的穀值大小呈反比.(3)由于冕洞形成過程中的太暘風高速流影響,電子通量具有13.4及27.4天的週期,峰值水平受控于太暘風速結構.
결합소파분석급교차소파분석방법,연구료지구동보궤도고능전자동태변화적다시간척도결구,분석료전자통량재불동주기수착태양풍속、지자지수D_(st)변화적구체특점.결과발현:(1)전자통량적장기변화수공우태양풍속,재태양활동저치년,전자통량치고,구유명현적13.4천,27.4천급187천주기;교차소파분석표명,전자통량적13.4천급27.4천주기수태양풍속주기변화신호적영향,187천주기변화수D_(st)지수주기변화신호적영향.(2)전자통량반년변화주요귀인우태양풍적구동작용,재매년적제100천급270좌우체도량차봉치,봉치대소불대칭,여D_(st)지수적곡치대소정반비.(3)유우면동형성과정중적태양풍고속류영향,전자통량구유13.4급27.4천적주기,봉치수평수공우태양풍속결구.
The wavelet analysis and the cross wavelet analysis are used to analyze the multi-time scale structure of geostationary high-energy electron variations,and the characteristics of the dynamic electron environment varying with the solar wind and the D_(st) index were presented.The results are as follows:(1)Long-term variations of electron flux are mainly controlled by the solar wind velocity.The electron flux enhances during the declining phase of the solar cycle with high solar wind velocity,and varies with 13.4-day,27.4-day and 187-day periodicities.The cross wavelet analysis shows that the 13.4-day and the 27.4-day periodicities are related to the periodicity signal of solar wind velocity,and the 187-day periodicities are related to the periodicity signal of the D_(st) index.(2)The 187-day periodicity of the geostationary electron flux is mainly due to the solar wind driver,and the electron flux reaches its peaks on about the 100th and 270th day of one year.The two peak values are not equivalent,while they are related to minimums of the D_(st) index.(3)Due to high speed solar wind streams which originate from trans-equatorial coronal holes,the electron flux varies with 13.4-day,and 27.4-day periodicities.The 27.4-day periodic variations are characterized by three phases:rapid increase,a more steady peak period and rapid decrease,and the electron flux peak level depends on solar wind velocity structure.