The Geomagnetical Effect of the Coronal Holes

The long and short term effects of the coronal holes to the geomagnetical field are analysed in this paper.The evolution of the equatorial coronal holes with the solar acticity cycle is closely related to the geomagnetic disturbances on belief level of α=0.01.It is found that the contributton of the equatorial coronal holes to the geomagnetic disturbance is not only at the solar activity minimun but also at the solar activity maximun.The result of the short term effect of the coronal holes to the geomagnetic field proved that the coronal holes is a source of the cyclical geomagnetic disturbance.