| 大地水准面高的计算及其在海底地形反演中的应用 |
| The Calculation of Geoid Height and Its Applicationin Seafloor Topography Inversion |
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| DOI： |
| 中文关键词: 海底地形 大地水准面高 频率域 相干性 EIGEN-6C4 |
| 英文关键词:seafloortopography geoid height frequency domain coherence EIGEN-6C4 |
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| 中文摘要: |
| 为充分挖掘海洋重力数据在反演海底地形中的应用潜力，尝试探索利用大地水准面高反演海底地形的技术途径，并以夏威夷-皇帝海山链拐点所在海区作为反演试验区进行验证。首先采用Belikov列推法计算伴随（缔和）勒让德函数，利用EIGEN-6C4地球重力场模型解算获取了分辨率为1角分的大地水准面高格网数值模型；尔后通过综合分析反演比例函数和转换函数特点、研究海区大地水准面高与海底地形的相干特性以及大地水准面高本身尺度特征获得了利用大地水准面高反演海底地形的频段范围；最终以试验海区大地水准面高为数据输入，构建了相应的海底地形模型（BNT模型），并与ETOPO1等海深模型进行比对分析。试验结果表明：BNT模型检核差值在一倍均方差范围检核点数量占比70.60%，相比正态分布更加集中；BNT模型检核精度低于ETOPO1等海深模型；海深模型检核精度随着水深增加不断提升，水深小于1 000 m时，海深模型相对误差出现较大发散现象；计算海域ETOPO1模型精度最高，GEBCO模型和DTU10模型检核精度相当。 |
| 英文摘要: |
| In order to fully tap the application potential by using marine gravity data to inverse seafloor topography, the inversion approach with geoid height is explored in this paper. Numerical analysis was carried out in the sea area where the inflection point of Hawaii-Emperor seamount chain is located. Firstly, associated Legendre functions (ALFs) was calculated by Belikov method, and geoid height model with 1-angular resolution was obtained by EIGEN-6C4 gravity field model. Then, the frequency range of seafloor topography inversion using geoid height was obtained by analyzing the characteristics of scale function and transform function, while studying the coherence between geoid height and seafloor topography and characteristics of geoid height itself. Finally, seafloor topography model (BNT model) was derived by geoid height in the test area. Compared with ETOPO1 model and some other models, the results show that the number of checking points accounts for 70.60% considering BNT model when checking difference is less than RMS, which is more centralized than normal distribution. The accuracy of BNT model is lower than that of ETOPO1 model and increases with the increase of sea depth. Relative error diverges greatly when sea depth is less than 1 000 m.Moreover, the accuracy of ETOPO1 model is the highest, and there is little difference between GEBCO model and DTU10 model. |
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