Time variability of the Earth's gravity field: Hydrological and oceanic effects and their possible detection using GRACE
Time variability of the Earth's gravity field: Hydrological and oceanic effects and their possible detection using GRACE
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DOI：
10.1029/98jb02844
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发表时间：
1998-12-10
影响因子：
3.9
通讯作者：
Bryan, F
中科院分区：
文献类型：
--
作者：
Wahr, J;Molenaar, M;Bryan, F
GRACE卫星的使命定于2001年发射，其目的是在5年的标称寿命内每2至4周高精度地绘制地球重力场图。重力场的变化是由地球内部和地球表面或其上方的质量重新分布引起的。因此，GRACE将能够约束涉及质量再分配的过程。在本文中，我们使用水文、海洋和大气模型的输出来估计重力场的变化（即，在大地水准面），由于这些来源。我们开发了一种方法来构建表面质量估计的GRACE重力系数。我们展示了模拟的结果，在那里我们使用合成GRACE重力数据，通过结合估计的地球物理信号和模拟GRACE测量误差，试图恢复水文和海洋信号。我们表明，GRACE可能能够恢复大陆储水量和海底压力的变化，在几百公里和更大的尺度上，在几个星期和更长的时间尺度上，精度接近2毫米的水在陆地上的厚度，和0.1毫巴或更好的海底压力。
The GRACE satellite mission, scheduled for launch in 2001, is designed to map out the Earth's gravity field to high accuracy every 2-4 weeks over a nominal lifetime of 5 years. Changes in the gravity field are caused by the redistribution of mass within the Earth and on or above its surface. GRACE will thus be able to constrain processes that involve mass redistribution. In this paper we use output from hydrological, oceanographic, and atmospheric models to estimate the variability in the gravity field (i.e., in the geoid) due to those sources. We develop a method for constructing surface mass estimates from the GRACE gravity coefficients. We show the results of simulations, where we use synthetic GRACE gravity data, constructed by combining estimated geophysical signals and simulated GRACE measurement errors, to attempt to recover hydrological and oceanographic signals. We show that GRACE may be able to recover changes in continental water storage and in seafloor pressure, at scales of a few hundred kilometers and larger and at timescales of a few weeks and longer, with accuracies approaching 2 mm in water thickness over land, and 0.1 mbar or better in seafloor pressure.