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geomagnetic storm (地)磁暴。

Many scientists have made efforts to study the relationships between the events of cmes and gcrs “ intensity variation . there are mainly two kinds of gcrs properties used to predict geomagnetic storms . one of them is gcrs “ anisotropy and the other is gcrs “ spectrum 國際上銀河宇宙線與cme之間的關系已經進行了很長時間的研究,用銀河宇宙線進行地磁暴預報主要分為利用銀河宇宙線的各向異性特征的變化來進行地磁暴預報或利用銀河宇宙線強度譜的變化來進行地磁暴預報。

We still analyzed the time - frequency variation properties of the data before several selected geomagnetic storms . the result shows that the gcrs “ intensity with period of 16 - 32 hours increased remarkably for those events that ocrs intensity increased before the geomagnetic storms 對于磁暴前銀河宇宙線強度增強的事件,銀河宇宙線周期為16 ? ? 32小時的信號都有較明顯的增強,部分事件銀河宇宙線周期為兒個小時的信號也明顯提高(如1991年的事件) 。

In addition , the study shows that the cmes “ traveling direction is also an important factor , which influence the intensity of the geomagnetic storms . we also analyzed gcrs data from beijing super - neutron - monitor ( snm ) by using fft and power spectrum method 我們對cme運動方向與磁暴強弱的關系進行了初步的研究,研究表明,同樣條件下,正對磁層頂的cme形成的磁暴更強,即cme的運動方向是影響磁暴強弱的一個重要因素。

Because catastrophic space weather events occur in general very suddenly , such as geomagnetic storms with sudden commencements . forbush decrease ( fds ) in ocrs intensity is also a kind of sudden event . the properties of these sudden events “ are very evident 山ttsh下降也是全球范圍內銀河宇宙線強度的突然下降,這是cme到達地球后對全球臺站記錄的宇宙線強度造成突然的影響,這些突發事件其突發特征非常明顯。

The statistical results show that there are about 66 . 7 % geomagnetic storms with precursors in gcrs . we can roughly judge the cmes “ direction when passing through the earth by using the two nm station data 其先兆特征為宇宙線強度的增加、減少和各向異性有較大的提高,分析結果表明采用這種方法進行分析,約66 . 7的大磁暴前有先兆。

We also made a statistical study on precursors appeared in gcrs before major and large geomagnetic storms only by using the two cusp stations “ nm data obtained at mcmurdo and thule 對大磁暴前銀河宇宙線強度的變化和各向異性進行的統計分析分析表明,銀河宇宙線強度在磁暴前是有先兆的。

What is a “ geomagnetic storm “ 什么是地磁暴?

geomancy

Increased radiation from the sun and occurrence of geomagnetic storms ( i . e . severe distortion of geomagnetic field of the earth ) may cause disturbances such as increases in density in the earth s upper atmosphere . these result in a greater drag on the movement of satellites and spacecraft , causing a slow - down or even a change in orbit 輻射的增加及地磁暴(即地球磁場急速變形)的出現,會導致地球上層大氣的擾動,例如空氣密度的上升,從而使衛星和太空船在航行時受到的阻力大增,航行速度因而減慢,甚至軌道亦會改變。

Many scientists have made efforts to study the relationships between the events of cmes and gcrs “ intensity variation . there are mainly two kinds of gcrs properties used to predict geomagnetic storms . one of them is gcrs “ anisotropy and the other is gcrs “ spectrum 國際上銀河宇宙線與cme之間的關系已經進行了很長時間的研究,用銀河宇宙線進行地磁暴預報主要分為利用銀河宇宙線的各向異性特征的變化來進行地磁暴預報或利用銀河宇宙線強度譜的變化來進行地磁暴預報。

Increased radiation from the sun and occurrence of geomagnetic storms i . e . severe distortion of geomagnetic field of the earth may cause disturbances such as increases in density in the earth s upper atmosphere . these result in a greater drag on the movement of satellites and spacecraft , causing a slow - down or even a change in orbit 輻射的增加及地磁暴即地球磁場急速變形的出現,會導致地球上層大氣的擾動,例如空氣密度的上升,從而使衛星和太空船在航行時受到的阻力大增,航行速度因而減慢,甚至軌道亦會改變。

More and more researches have shown that most of the intense geomagnetic storms are caused by fast coronal mass ejections in interplanetary space ( icmes ) . though the ace satellite can provide solar wind data in almost real time for prediction of geomagnetic storms , the time interval is too short ( shorter than 30 - min ) for effective predictions of major geomagnetic storms 位于拉格朗日點的ace衛星可以提供近實時的太陽風數據,但依據ace衛星太陽風數據進行地磁暴預報,時間的提前量非常有限,對于大地磁暴,這個時間提前量往往不超過30分鐘,這樣的時間提前量對于實際應用來說,是不能令人滿意的。

While the magnetic field on the earth ( which traps charged particles encircling the earth into radiation belts called the van allen belts ) normally protects our planet from the solar wind , it may be deformed in the event of violent solar wind , resulting in a geomagnetic storm on earth 雖然地球上的磁場能將環繞地球的帶電荷粒子困于其輻射帶( vanallenbelts ) ,一般能有效阻擋太陽風,但在猛烈太陽風情況下它可能受影響而變形,導致地磁暴的出現。

We still analyzed the time - frequency variation properties of the data before several selected geomagnetic storms . the result shows that the gcrs “ intensity with period of 16 - 32 hours increased remarkably for those events that ocrs intensity increased before the geomagnetic storms 對于磁暴前銀河宇宙線強度增強的事件,銀河宇宙線周期為16 ? ? 32小時的信號都有較明顯的增強,部分事件銀河宇宙線周期為兒個小時的信號也明顯提高(如1991年的事件) 。

While the magnetic field on the earth which traps charged particles encircling the earth into radiation belts called the van allen belts normally protects our planet from the solar wind , it may be deformed in the event of violent solar wind , resulting in a geomagnetic storm on earth 雖然地球上的磁場能將環繞地球的帶電荷粒子困于其輻射帶van allen belts ,一般能有效阻擋太陽風,但在猛烈太陽風情況下它可能受影響而變形,導致地磁暴的出現。

In addition , the study shows that the cmes “ traveling direction is also an important factor , which influence the intensity of the geomagnetic storms . we also analyzed gcrs data from beijing super - neutron - monitor ( snm ) by using fft and power spectrum method 我們對cme運動方向與磁暴強弱的關系進行了初步的研究,研究表明,同樣條件下,正對磁層頂的cme形成的磁暴更強,即cme的運動方向是影響磁暴強弱的一個重要因素。

Because catastrophic space weather events occur in general very suddenly , such as geomagnetic storms with sudden commencements . forbush decrease ( fds ) in ocrs intensity is also a kind of sudden event . the properties of these sudden events “ are very evident 山ttsh下降也是全球范圍內銀河宇宙線強度的突然下降,這是cme到達地球后對全球臺站記錄的宇宙線強度造成突然的影響,這些突發事件其突發特征非常明顯。

The ocrs intensity with the periods of 32 - 64 hours increased remarkably for those events that ocrs intensity decreased before the geomagnetic storms , while the intensity of ocrs with the periods shorter than 24 - hour are not obvious 對于磁暴前銀河宇宙線強度減弱的事件,如1982年7月事件,周期為32 ? ? 64小時的信號幅度有較明顯的增強,而周期低于24小時的信號變化非常不明顯。

The field forms a protective shell called magnetosphere that has a radius around 10 times that of the solid earth . but strong eruptions on the solar surface can seriously distort this shell , creating geomagnetic storms 地球磁場形成一個大小約地球直徑十倍稱為磁層的保護殼,當太陽表面出現猛烈的爆發,便會嚴重扭曲這個保護殼,形成磁暴。

The statistical results show that there are about 66 . 7 % geomagnetic storms with precursors in gcrs . we can roughly judge the cmes “ direction when passing through the earth by using the two nm station data 其先兆特征為宇宙線強度的增加、減少和各向異性有較大的提高,分析結果表明采用這種方法進行分析,約66 . 7的大磁暴前有先兆。