基于地表负载理论反演地心运动

发布时间：2018-07-10 18:29

本文选题：CGCS2000 + 地心运动　；参考：《辽宁工程技术大学》2014年硕士论文

【摘要】：自20世纪80年代,随着空间大地测量技术(VLBI、SLR、LLR和DORIS等)的迅猛发展,特别是全球导航卫星系统(GNSS)技术的日臻成熟,建立和维持全球/区域地心坐标系统己经成为现实。地心坐标系统的原点位于总地球椭球中心(地球质心),椭球旋转轴指向协议地极,起始大地子午面与零子午面重合,即x和z轴的定向由某一历元的EOP确定,y轴与x轴和z轴构成空间右手直角坐标系。由于地球上发生的运动和形变十分复杂,因此我们只能在一定量级上对一些影响较大且有规律的因素加以模拟并改正,从而建立并维持一个达到一定精度的地球参考框架。以ITRF为代表的高精度地心参考框架的维持需要考虑板块运动(主要沿水平方向),冰期后地壳均衡调整(主要沿垂直方向),地壳构造形变,地表负载变化以及地球质心运动。地球质心(以下简称地心)是指整个地球系统的质量中心CM(center-of-mass),包括固体地球和覆盖在固体地球表面的液体层(包括海洋、大气、陆地上的河流、湖泊及冰川等)。地心运动是由地球各圈层的物质运动所引起的,全球大气、海洋和地表水的季节性变化是地球质心周年运动的主要地球物理机制,因此可通过这些地球物理因素的季节性变化来较好地反演地心的周年运动。此外,地心运动还有长周期分量,这是由于冰期后地壳均衡调整所引起的。因为地心坐标系统的原点定义在地心,地面点的坐标是相对于地心的位置确定的,所以地心的位置变化必然会引起地面点坐标的改变,地心运动将成为动态地心参考框架维持中需要考虑的重要因素。本文基于地表负载理论,分别利用IGS所提供的全球范围内的IGS05框架点的位移、ECCO模型所提供全球范围的分辨率为1.O°×1.O°的海底压强数据和NCEP所提供的全球范围的分辨率为2.5°×2.5°的大气负载数据,研究地表质量负载变化所引起的固体地球形变,以及由此所产生的地表重力场的变化,进而反演得到了近10年和12年地心位置变化时间序列,并利用功率谱分析的方法探测了地心运动的周期项,最后分别拟合得到了地心运动年周期项的振幅和相位。
[Abstract]:Since the 1980s, with the rapid development of space geodetic technology (VLBIN SLRLLR and DORIS etc.), especially the global navigation satellite system (GNSS) technology, the establishment and maintenance of global / regional geocentric coordinate system has become a reality. The origin of the geocentric coordinate system is located at the center of the ellipsoid of the total earth (the center of the earth's mass). The axis of rotation of the ellipsoid points to the agreement of the earth pole, and the initial meridional plane coincides with the zero meridional plane. In other words, the orientation of x and z axis is determined by EOP of a certain epoch to form a right-hand coordinate system with x axis and z axis. Because the movement and deformation on the earth are very complex, we can only simulate and correct some influential and regular factors in a certain order of magnitude, so as to establish and maintain a frame of reference for the earth with certain precision. The maintenance of high precision geocentric reference frame represented by ITRF needs to consider plate movement (mainly along horizontal direction), postglacial crustal equalization adjustment (mainly along vertical direction), crustal tectonic deformation, surface load change and earth centroid movement. Earth centroid (hereinafter referred to as geocentric) refers to the mass center CM (center-of-mass) of the whole earth system, including solid earth and liquid layer covering the surface of solid earth (including ocean, atmosphere, rivers, lakes and glaciers on land, etc.). The geocentric motion is caused by the movement of matter in every layer of the earth, and the seasonal variation of the global atmosphere, ocean and surface water is the main geophysical mechanism of the annual motion of the earth's centroid. Therefore, the seasonal variation of these geophysical factors can be used to better invert the annual motion of the geocentric. In addition, the geocentric movement has a long period component, which is caused by the postglacial crustal equilibrium adjustment. Because the origin of the geocentric coordinate system is defined in the geocentric, the coordinate of the ground point is determined relative to the geocentric position, so the change of the geocentric position will inevitably lead to the change of the ground point coordinate. Geocentric motion will be an important factor to be considered in the maintenance of dynamic geocentric reference frame. This paper is based on the theory of surface load. Using the global IGS05 frame point displacement and ECCO model provided by IGS, respectively, the global pressure data with a resolution of 1.0 掳脳 1.O 掳and the atmospheric load data with a global resolution of 2.5 掳脳 2.5 掳provided by NCEP are obtained, respectively. The deformation of solid earth caused by the change of surface mass load and the change of ground gravity field are studied, and the time series of geocentric position change in recent 10 and 12 years are obtained. The periodic term of the geocentric motion is detected by power spectrum analysis, and the amplitude and phase of the annual period term of the geocentric motion are obtained respectively.
【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P228.4

【参考文献】