华北地区现行的地震重力监测网由于独立联测,自成体系,绝对控制点较少,获得的重力场动态变化图像在绝对控制较弱的地区会产生畸变,也不能有效的消除仪器标定系统所引起的测量误差.本文以华北大网作为控制网,结合绝对重力点进行联合平差计算,使各省区地震重力监测网平差精度提高了(0～4)×10-8 m/s2,平差起算基准相统一,绝对控制较弱的地区畸变减小.采用相关系数检验法,对华北地区各省区地震重力监测网2010年二期重力平差计算结果进行检验,部分重力点位系统误差高达60×10-8 m/s2,经过系统误差改正后,重力场动态变化趋于一致.经过各项改正后,华北地区2010年重力场动态差分图像对地震前兆具有更好的反映.%There are nine repeated relative gravity observation networks in northern China, whose Measurements of these networks are carried out independently and they have different control points and data processing methods. Gravity value changes far away from the control points are always imprecise and contain systematic error. In this paper, we use absolute gravity points and The Large North China Gravity Network as control gravity network, and calculate combined adjustment of the nine repeated relative gravity networks. The precision of the repeated relative gravity observation networks increased by 0~4 × 10-8 m/s2 and the nine repeated relative gravity observation networks can be united as a whole gravity network. Systematic error of some relative gravity observation networks can reach 60×10-8 m/s2. We also calculated reliability of correlation coefficients of relative gravity observation networks and made systematic error correction. After the systematic error correction, it is expected that repeated gravity data can better response to earthquake preparation. At last, we analysed the changes of gravity field of 2010 in northern China.
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