摘要
在不考虑地壳均衡条件下,从重力场基本理论出发推导了重力异常/扰动与海深信息之间的近似解析关系,其中扰动重力反演海底地形的模型较之重力异常更加简洁.通过对反演模型级数展开式的深入分析表明,在重力数据分辨率数值小于海深分辨率时并不明显收敛,因此在用重力数据反演高分辨率海底地形时应顾及展开级数的高阶项并采取相应处理方法.在大量统计分析基础上,构建了局部海域扰动重力数据反演高分辨率海底地形的非线性序列相关方法,该方法利用少量船测重力/水深测线数据获取非线性相关参数,而后利用卫星测高重力数据按非线性相关函数模型反演海底地形.试验分析表明,2次非线性相关函数反演效果表现较优,对于海底地形平缓海域,1°×1°区域内单条船载测线数据获得的相关参数即可达到2%相对精度.对于海底地形复杂海域,论文方法适用范围应该尽量缩小,30′×30′区域范围基于单条船载测线数据反演的相对精度可优于7%.从论文试验结果分析,海底地形与重力数据之间存在2次非线性相关函数特征,且这种特征在高分辨率情况下仍然适用,利用非线性函数模型并结合稀疏船载测量数据、密集卫星测高重力数据可为局部海域高分辨率海底地形反演提供一种可行的解算方法.
Based on the basic theory of gravity field, the approximate analytic relationship between gravity anomaly/disturbance and bathymetric information is deduced without considering the isostasy of crust. By analyzing the series expansion of the inversion model, it is shown that the resolution of gravity data does not converge when the resolution of gravity data is less than that of bathymetric data, therefore, the high-order terms of the expansion series should be considered and the corresponding processing methods should be adopted in the inversion of high-resolution seabed topography from gravity data. On the basis of a large number of statistical analysis, a nonlinear sequence correlation method for retrieving high-resolution seabed topography from disturbed gravity data in local sea area is proposed, which can be used to inverse the seabed topography by using satellite altimetry gravity data and small ship-borne surveying data. The experimental results show that the 2-order nonlinear correlation function has better performance, and the relative accuracy can reach 2% for the sea area with flat bottom topography based on the parameters obtained from the single ship-borne line survey data in the area of 1°×1°. For the sea area with complex seabed topography, the scope of application of the method in this paper should be reduced as far as possible, the relative accuracy of 30′×30′ area inversion based on single shipborne survey line data can be better than 7%. From the analysis of the test results in this paper, there is a quadratic nonlinear correlation function feature between seabed terrain and gravity data, and this feature is still applicable in the case of high resolution. Using the nonlinear function model,combined with sparse shipborne measurement data and dense satellite altimetry gravity data,a feasible solution method for high-resolution seabed terrain inversion in local sea areas can be provided.
作者
翟振和
孙中苗
马健
李楠
管斌
欧阳明达
ZHAI ZhenHe;SUN ZhongMiao;MA Jian;LI Nan;GUAN Bin;OUYANG MingDa(State Key Laboratory of Geo-Information Engineering,Xi'an 710054,China;State Key Laboratory of Astronautics Dynamics,Xi'an 710043,China)
出处
《地球物理学进展》
CSCD
北大核心
2023年第2期631-640,共10页
Progress in Geophysics
基金
国家自然科学基金项目(41674082)资助。
关键词
海底地形
卫星测高
船载重力/水深测量
扰动重力
2次非线性相关函数
Seabed topography
Satellite altimetry
Ship-borne gravimetry/bathymetry
Disturbed gravity
2 order nonlinear function model
