大地水准面起伏对国际地磁参考场计算的间接影响

摘要

在利用国际地磁参考场模型计算主磁场时,往往采用海拔高而非大地高,并且忽略了大地水准面起伏的间接影响.通过全球的实际计算表明,若忽略大地水准面起伏,可引起地表主磁场的北向、东向、垂向与水平分量以及总模量的误差范围分别为—2.37～1.59 nT、—0.51～0.33 nT、—1.95～2.09 nT、—2.37～1.59 nT与—2.39～1.82 nT.%When calculating the main field using the international geomagnetic reference field(IGRF) model,the height above the mean sea level,instead of the geodetic height,is utilized and the corresponding indirect impact of the geoid undulation is often ignored.Through global practical computation,the results show that neglecting the geoid undulation will introduce the errors of —2.37～1.59 nT,—0.51～0.33 nT,—1.95～2.09 nT,—2.37～1.59 nT,and —2.39～1.82 nT for the north,east,vertical and horizontal components and total intensity of the main field on the Earth's surface,respectively.