重力仪一次项系数对重力场动态变化的影响研究

利用2011~2013喜马拉雅项目在南北地震带北段获得的10余个绝对重力值作为基准,运用甘肃、宁夏和河西3个重力网的数据对各重力仪一次项系数进行重新解算,获得重力场动态变化。结果显示:1)2011-05~2013-06的重力场反映出,青藏高原深部物质向北东运移过程中出现自西南向东北、由负向正的大空间尺度趋势性显著重力变化;2)LCR-G型及Burris型金属弹簧重力仪的一次项较稳定,基本不变,而CG-5型石英弹簧重力仪的一次项逐年减小,应每年利用绝对基准进行实测标定;3)利用绝对基准进行实测一次项标定后,重力场总的变化趋势与利用长基线标定的一次项计算结果基本一致,只是量级有所减小。

Research on the Effect of One Degree Term of Chromatic Polynomial of Gravimeter on Gravity Dynamic Change

On the basis more than ten absolute gravity values of the Himalaya project in the north and the south segments during 2011-2013, gravity dynamic variations are obtained according to the recalculated one-degree term of chromatic polynomial of gravimeter in the network of Gansu, Ningxia and Hexi. The results show: 1) Gravity variation is fairly dramatic in the Qinghai-Tibet plateau, which reflects tendency change on large spatial scales in the process that deep material moves to the northeast. 2) One-degree term of chromatic polynomial remains stable with respect to LCR-G and Burris| CG-5 decreased gradually (it should be calibrated according to the absolute values). 3) A general tendency of change of gravity variation after we used absolute values to calibrate the one-degree term of chromatic polynomial is consistent with long baseline calibration, data analysis is more reliable which is decreased.