Characteristics of the secular variation and secular acceleration distributions of the main geomagnetic field for the CHAMP satellite

Using the new geomagnettic model POMME-4. 2S derived from the CHAMP satellite data, we have analyzed the characteristics of the distributions of seven secular variation components (X) over dot, (Y) over dot, (Z) over dot, (H) over dot, (I) over dot (D) over dot and three secular acceleration components in the global area and in China. We also compared the differences of the distributions between the secular variation models POMME-4. 2S and CGRF-SV (Chinese Geomagnetic Reference Field-Secular Variation). The results suggest that the quadrupole plays the main role in the geomagnetic secular variation, and the octupole occupies the largest portion in the contribution to the secular acceleration. The global secular variation decreased more than that increased in 2004. 0 A. D., under the background of a decreasing trend of the geomagnetic field. The secular acceleration changes more in the middle and lower latitudes than that in the higher latitude. Moreover, the negative and positive magnetic anomalies of Y and Z components form several interlaced areas along the longitude, and these two kinds of anomalies of X component are nearly symmetrical to the equator. An evident relationship is available for the magnetic anomaly distributions of the three secular acceleration components X, Y, Z. That is, the foci of X magnetic anomalies are present by the south and north, and Y by the east and west sides of the foci of 2 magnetic anomalies. The amount of change of the secular variation and acceleration in China are small and their distributions are relatively uniform.