Mass redistribution to be revealed by GRACE project
Mass redistribution to be revealed by GRACE project
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发表时间：
2004-03
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通讯作者：
Cheng Huang;Xiaogong Hu
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作者：
Cheng Huang;Xiaogong Hu
2002年3月，美国和德国共同资助的GRACE重力和气候研究双卫星发射成功，将提供精度空前的时变重力模型。这两颗完全相同的卫星相距约220公里，在近极地轨道上，高度为300~500公里。在船上的GPS数据和加速度计测量被用来精确地确定轨道，双卫星之间的距离变化率测量被用来恢复重力，在几百公里或更大的空间尺度上，精度比以前高得多。GRACE时变重力场模型所获得的质量再分布数据将对地球物理研究产生深远的影响。尽管GRACE重力场的设计寿命为5年，但模拟研究表明，GRACE重力场将提供有关冰盖长期变化和全球平均海平面变化的重要信息。在季节时间尺度上，GRACE重力仪能够探测到小于1厘米的陆地水变化或小于1毫巴的海底压力变化。除了社会和经济的重要性，质量再分配的知识有助于我们理解水的质量和能量转移。本文的目的是提供必要的背景，了解各种过程的质量再分配，并提出应用研究的重点放在中国和邻近的海洋。
The successful launch of the GRACE twin satellites in March, 2002 for gravity and climate study, which is a US and Germany co-sponsered project, will deliver time-varying gravity models with unprecedented precision. The two identical satellites are about 220 km apart on a nearly polar orbit with an altitude of 300~500 km. On aboard GPS data and accelorometer mearuments are used to precisely determine the orbits, and range change rate measurements between the twin satellites are used to recover gravity to much higher precision than before at spatial scales of a few hundred km and larger. The mass redistribution data derived from the GRACE time-varying gravity models will have profound impacts on various geophysical research topics. Despite of its designed 5-year lifetime, simulation studies have shown that the GRACE gravity will provide important information on secular change of ice sheets, and global mean sea level change. At seasonal time scales, GRACE gravity is capable to detect land water change less than 1 cm or change in oceanic bottom pressure less than 1 mbar. Besides social and economical importance, knowledge in mass redistribution helps us understand both water mass and energy transfer. The purpose of this paper is to provide necessary background for understanding various prosesses of mass redistribution, and to propose application studies focusing on China and neighboring oceans.