武汉基准台气压对重力潮汐观测的影响

Influence of atmospheric pressure on tidal gravity at Wuhan station

武汉基准台超导重力仪观测重力残差和台站气压的相关分析结果表明，重力残差信号主要是由气压变化引起的。本文在频率和时间域内分别测定了大气重力导纳值，结果说明在时域内的导纳值为－０．３０７μＧａｌ／ｈＰａ（１Ｇａｌ＝１ｃｍ／ｓ２），而在频域内的大气重力导纳值变化范围在０．３～０．５μＧａｌ／ｈＰａ之间，这一结果与理论模拟计算相符。对实测资料作气压改正的结果表明气压改正效果非常显著，各频段内的观测残差振幅均有明显降低，在潮汐频段内的信噪比有不同程度的提高。进一步分析说明。

The analysis results of the correlation between the tidal gravity residuals, observed with a superconducting gravimeter at Wuhan fundamental station, and the atmospheric pressure demonstrates that the gravity residuals are mainly influenced by the air pressure variation. In this study, the atmospheric gravity admittances in both frequency and time domains are determined respectively. The results show that the average atmospheric admittance is as of -0.307 μGal/hPa in time domain and is as of in the range from 0.3 to 0.5 μGal/hPa in frequency domain. It is in agreement with those calculated using an theoretical model. The atmospheric pressure correction on the tidal gravity observations is effective, the observed residuals are reduced significantly at various frequency bands. The ratio signal to noise at tidal wave band is improved. The further analysis shows that we can obtain the more reasonable results when doing pressure correction using atmospheric gravity admittances in frequency domain.