Downward continuation of gravity field

重力场向下延续

• 批准号: 8300-2013
• 负责人: Vanicek, Petr
• 金额: $ 1.84万
• 依托单位: University of New Brunswick
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=592915
• 关键词: Downward; continuation; gravity; field

Gravity is observed on the earth's surface but for the geoid computation it is needed at the sea level (on the geoid): it has to be "continued downward" onto the sea level through topographical masses. In our approach to geoid determination, the best approximation of topographical masses is subtracted from actual topography and we consider the result (Earth without topography) to represent the situation in the "NT space". In fact, we replace topography by a condensation layer on the geoid and call this new space the "Helmert space". Helmert's space is thus the NT space augmented by the condensation layer. In both the NT and Helmert's space, the downward continu-ation is carried out through a part of space that is as void of mass as we can possibly make it.

重力是在地球表面观测到的，但对于大地水准面计算，它需要在海平面（在大地水准面上）：它必须通过地形质量“持续向下”到海平面上。在我们的大地水准面确定方法中，从实际地形中减去地形质量的最佳近似值，我们考虑结果（没有地形的地球）来代表“NT空间”中的情况。事实上，我们用大地水准面上的凝结层代替地形，并将这个新空间称为“赫尔默特空间”。因此，海尔默特空间是由凝结层扩大的NT空间。在NT和Helmert空间中，向下的延续都是通过空间的一部分进行的，这部分空间是我们所能制造的最大的质量空洞。