International Collaboration on the Study of Geodynamics of Subglacial Lake Vostok, Antarctica

1969年，Schneider（1970）在Vostok站（78.466°S, 106.832°E, 3478 m asl）安装了一台Askania Gs-11重力仪。我们用BAYTAP-G和-L （Tamura et al., 1991）程序重新访问和分析了数据。对于NAO99b （Matsumoto et al., 1999）和FES99 （Lefevre et al., 2000）两个全球海潮模型，我们估计了负荷潮汐。对于K1波，获得的残余振幅为1.91±0.25μ Gal，而对于M2波，获得的残余振幅为1.24±0.14 μ Gal。与Dietrich等人（2001）的结果相比，相关不确定性降低到三分之一。有趣的是，K1波约为900相引线，而M2波约为1800相引线（延迟）。重力变化与垂直位移的换算系数为-0.29μ Gal/mm，位移范围约为±10 mm；这与实际观测到的2002/2003季节GPS垂直运动的最小二乘意义相匹配。湖面上的气压差会造成气压差逆效应，在数天至数周的时间尺度上，高度变化可达40毫米。通过2002/2003年夏季在湖泊南部的差分GPS观测，可以验证这一效应以及差分潮汐运动。测量到的最大组分的振幅和相位对应于微分平衡潮汐的各自值。利用1996年的4张ERS-1/ 2串联干涉图分析了地表位移的空间格局。这些测量显示了一个隆起，有一个宽的潮汐弯曲带，振幅不同，但几何形状相似。此外，可以得出结论，湖泊内相关的水再分配形成了湖泊整体水循环的额外组成部分

In 1969, an Askania Gs-11 gravimeter was operated at Vostok Station (78.466°S, 106.832°E, 3478 m asl) by Schneider (1970). We revisited and analyzed the data with a BAYTAP-G and -L (Tamura et al., 1991) program. For the two global ocean tide models of NAO99b (Matsumoto et al., 1999) and FES99 (Lefevre et al., 2000), we estimated the load tides. For the K1 wave, the obtained residual amplitude was 1.91 ± 0.25μ Gal, while for the M2 wave it was 1.24 ± 0.14,u Gal. The associated uncertainty reduced to one-thirds as compared with the results by Dietrich et al. (2001). It is interesting that K1 wave is about 900 phase-leaded, while M2 wave is about 1800 phase-leaded (delayed). With a conversion coefficient of -0.29μ Gal/mm from gravity variation to vertical displacement, the displacement was in the range of about ±10 mm ; which is found to match the actually observed 2002/2003-season GPS vertical motion in a least square sense. Air pressure differences above the lake cause a differential inverse barometer effect with resulting height changes of up to 40 mm on time scales from days to weeks. The effect could be verified, together with the differential tidal motions, by differential GPS observations in the southern part of the lake during the 2002/2003 summer season. The measured amplitudes and phases of the largest constituents correspond to the respective values of the differential equilibrium tides. Four ERS-1/-2 tandem interferograms of 1996 were used to analyze the spatial pattern of the surface displacement. These measurements reveal a bulge with a wide tidal flexure zone of varying amplitude but a similar geometry. Moreover, it can be concluded that the associated water redistribution within the lake forms an additional component of the overall water circulation in the lake