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(duì)大磁暴前銀河宇宙線強(qiáng)度的變化和各向異性進(jìn)行的統(tǒng)計(jì)分析分析表明,銀河宇宙線強(qiáng)度在磁暴前是有先兆的。