Increasing ice loss of the Antarctic Ice Sheet (AIS) due to global climate change affects the orientation of the Earth’s spin axis with respect to an Earth-fixed reference system (polar motion). Here the contribution of the decreasing AIS to the excitation of polar motion is quantified from precise time variable gravity field observations of the Gravity Recovery and Climate Experiment (GRACE) and from measurements of the changing ice sheet elevation from altimeter satellites. While the GRACE gravity field models need to be reduced by noise and leakage effects from neighboring subsystems, the ice volume changes observed by satellite altimetry have to be converted into ice mass changes. In this study we investigate how much individual gravimetry and altimetry solutions differ from each other. We show that due to combination of individual solutions systematic and random errors of the data processing can be reduced and the robustness of the geodetic derived AIS polar motion excitations can be increased. We investigate the interannual variability of the Antarctic polar motion excitation functions by means of piecewise linear trends. We find that the long-term behavior of the three ice sheet subregions: EAIS (East Antarctic Ice Sheet), WAIS (West Antarctic Ice Sheet) and APIS (Antarctic Peninsula Ice Sheet) is quite different. While APIS polar motion excitations show no significant interannual variations during the study period \(2003-2015\), the trend of the WAIS and EAIS polar motion excitations increased in 2006 and again in 2009 while it started slightly to decline in 2013. AIS mass changes explain about \(45\%\) of the observed magnitude of the polar motion vector (excluding glacial isosatic adjustment). They cause the pole position vector to drift along \(59^{\circ }\) East longitude with an amplitude of 2.7 mas/yr. Thus the contribution of the AIS has to be considered to close the budget of the geophysical excitation functions of polar motion.

由于全球气候变化，南极冰盖（AIS）的冰损失增加，影响了地球自旋轴相对于固定于地球的参考系统的方向（极运动）。在这里，从重力恢复和气候实验（GRACE）的精确时变重力场观测值以及高度计卫星对冰盖高度变化的测量结果中，可以确定AIS下降对极性运动激发的贡献。虽然GRACE重力场模型需要通过邻近子系统的噪声和泄漏影响来减小，但卫星测高仪观测到的冰量变化必须转换为冰量变化。在这项研究中，我们研究了重力法和测高法解决方案彼此之间有多少不同。我们表明，由于各个解决方案的组合，可以减少数据处理的系统误差和随机误差，并且可以提高大地测量得出的AIS极运动激发的鲁棒性。我们通过分段线性趋势调查南极极运动激发函数的年际变化。我们发现三个冰盖子区域的长期行为：EAIS（南极冰盖），WAIS（南极冰盖）和APIS（南极半岛冰盖）有很大的不同。尽管APIS极运动激发在研究期间没有显示出明显的年际变化 我们通过分段线性趋势调查南极极运动激发函数的年际变化。我们发现三个冰盖子区域的长期行为：EAIS（南极冰盖），WAIS（南极冰盖）和APIS（南极半岛冰盖）有很大的不同。尽管APIS极运动激发在研究期间没有显示出明显的年际变化 我们通过分段线性趋势调查南极极运动激发函数的年际变化。我们发现三个冰盖子区域的长期行为：EAIS（南极冰盖），WAIS（南极冰盖）和APIS（南极半岛冰盖）有很大的不同。尽管APIS极运动激发在研究期间没有显示出明显的年际变化\（2003-2015 \），WAIS和EAIS极运动激发的趋势在2006年和2009年再次增加，而在2013年开始略有下降。AIS的质量变化解释了观测量的\（45 \％\）极移矢量的矢量（不包括冰川等渗调整）。它们使磁极位置矢量沿\（59 ^ {\ circ} \）东经漂移，幅度为2.7 mas / yr。因此，必须考虑AIS的贡献以关闭极运动的地球物理激发函数的预算。