| 联合多代卫星测高和多源重力数据的局部大地水准面精化方法 |
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| 引用本文： | 吴怿昊,罗志才.联合多代卫星测高和多源重力数据的局部大地水准面精化方法[J].地球物理学报,2016,59(5):1596-1607. |
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| 作者姓名： | 吴怿昊 罗志才 |
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| 作者单位： | 1. 武汉大学测绘学院, 武汉 430079;2. 武汉大学地球空间环境与大地测量教育部重点实验室, 武汉 430079;3. 武汉大学测绘遥感信息工程国家重点实验室, 武汉 430079 |
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| 基金项目： | 国家自然科学基金(41374023,41131067),武汉大学地球空间环境与大地测量教育部重点实验室开放基金项目(15-02-08),国家留学基金(201306270014)资助. |
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| 摘 要： | 本文研究了基于泊松小波径向基函数融合多代卫星测高及多源重力数据精化大地水准面模型的方法.分别以沿轨垂线偏差和大地水准面高高差作为卫星测高观测量,研究了使用不同类型测高数据对于大地水准面建模精度的影响.针对全球潮汐模型在浅水区域及部分开阔海域精度较低的问题,引入局部潮汐模型研究了不同潮汐模型对于大地水准面的影响.数值分析表明:相比于使用沿轨垂线偏差作为测高观测量,基于沿轨大地水准面高高差解算得到的大地水准面模型的精度更高,特别是在海域区域,其精度提高了2.3cm.由于使用沿轨大地水准面高高差作为测高观测量削弱了潮汐模型长波误差的影响,采用不同潮汐模型对大地水准面解算的影响较小.总体而言,船载重力及测高观测数据在海洋重力场的确定中呈现互补性关系,联合两类重力场观测量可以提高局部重力场的建模精度.
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| 关 键 词： | 卫星测高 泊松小波径向基函数 沿轨大地水准面高高差 局部潮汐模型 局部大地水准面精化 |
| 收稿时间： | 2015-05-26 |
The approach of regional geoid refinement based on combining multi-satellite altimetry observations and heterogeneous gravity data sets |
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| WU Yi-Hao,LUO Zhi-Cai.The approach of regional geoid refinement based on combining multi-satellite altimetry observations and heterogeneous gravity data sets[J].Chinese Journal of Geophysics,2016,59(5):1596-1607. |
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| Authors: | WU Yi-Hao LUO Zhi-Cai |
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| Institution: | 1. School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China;2. Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, Wuhan University, Wuhan 430079, China;3. State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan 430079, China |
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| Abstract: | With the increasing multi-satellite altimetry data sets of unprecedented accuracy and spatial resolution, the marine geoid could be improved substantially. In the meanwhile, the traditional gravimetric measurements, e.g., terrestrial, shipboard and airborne gravity observations, could also be used to further improve the accuracy of the regional geoid. This paper focuses on the role of satellite altimetry in geoid determination as well as the proper combination of multi-satellite altimetry data sets and heterogeneous gravity observations for regional geoid refinement.#br#Based on the remove-compute-restore methodology, the residual disturbing potential is parameterized by using Poisson wavelets radial basis functions (RBFs). Meanwhile, the long- and short-wavelength part of the gravity field is represented by global gravity model (GGM) and residual terrain model (RTM), respectively. To choose the proper functional model of satellite altimetry data, different observations derived from sea surface height (SSH), i.e., along-track deflection of vertical (DOV) and difference of geoidal height (DGH) are evaluated for their performances in regional geoid modeling. Numerical experiments show that using along-track DGH as satellite altimetry observations derives a better geoid model, the accuracy of which is improved by 0.34 cm, 0.27 cm, 1.4 cm and 2.3 cm in Netherlands, Belgium, England and relevant marine regions, respectively. The main reason is that we use geoid slope to compute DOV, which may introduce large approximation errors that propagate into regional geoid modeling. Thus, we suggest using DGH as satellite altimetry observations.#br#As the quality of global tide model is doubtful in shallow water areas, it may introduce errors to satellite altimetry-derived observations. In order to find the proper tide model for data pre-processing and investigate the effect on the geoid caused by the choice of the tide models, a global tide model called GOT4.7 and regional tide model named DCSM are used in geoid modeling, respectively. Together with heterogeneous gravity data, DGH derived from global and regional tide model are used for two geoid computation, respectively. The difference between geoid based on different tide models is at a mm level, which concentrates in shallow water and specific open sea areas. The evaluation of two geoids show the effect on geoid introduced by different tide models may be negligible as the accuracy of geoid obtained from DCSM is only improved by mm level. However, a regional tide model with high accuracy is always preferable for reducing the relevant errors in satellite altimetry data pre-processing.#br#Moreover, the role of satellite altimetry and shipboard gravity data in marine geoid determination is studied. The result shows these two data sets are complementary with each other. Numerical experiments show the best result can be derived when satellite altimetry and shipboard data together with the other two data sets are combined for geoid modeling, the accuracy of which is 1.39 cm, 2.81 cm, 4.12 cm and 5.43 cm in Netherlands, Belgium, England and relevant marine regions, respectively. While the accuracy of geoid is decreased to 1.99 cm, 3.22 cm, 4.42 cm and 8.09 cm in the corresponding regions, respectively if the geoid is modeled without satellite altimetry data set. Similarly, the accuracy of geoid is also decreased without incorporating shipboard gravity data, which reduces to 2.15 cm, 3.61 cm, 5.46 cm and 8.15 cm over these regions, respectively. Thus, we suggest to combine satellite altimetry and shipboard gravity data set in marine gravity field determination. |
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| Keywords: | Satellite altimetry Poisson wavelets radial basis functions Along-track difference of geoidal height Regional tide model Regional geoid refinement |
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