中文摘要：

大陆上用重力数据和GPS水准数据确定（似）大地水准面,海洋上用卫星测高数据确定（似）大地水准面.由于沿海地区和近岸海域往往缺少完好的重力数据,近岸海域卫星测高数据质量相对较差,两类大地水准面在陆海相接区域精度偏低且存在拼合差.纯几何方法拟合陆海局部区域大地水准面,不能顾及大地水准面的物理特性,拟合结果不稳定.顾及到大地水准面的物理特性,依据其在局部所应满足的数学物理方程,拟合陆海局部区域大地水准面问题,转化为Laplace第一边值问题.讨论了有限元法衔接陆海局部区域大地水准面的数学思想,给出了相应的数学模型.

英文摘要：

The mainland geoid is derived mainly from land gravity data and GPS measurements, and the ocean geoid is derived mainly from the satellite altimeter data. The difference between mainland geoid and ocean geoid along their merge boundary area is caused because of the sparse gravity data and the poor quality of satellite altimeter data. Taking account of the physical characteristics of geoid, and according to the equations of mathematical physics of geoid in a local area, we transform the mainland-ocean merge geoid problem into the Laplace boundary value problem. Then, the ideas of mathematics joining the mainland geoid and the ocean geoid along their merge boundary area is discussed based on the finite element method, and a relevant mathematical model is given in the paper.