Computation of Diverse Terrain Effects on Various External Gravity Field Elements

PAGravf4.5 establishes a unified analytical algorithm framework for computing diverse terrain effects on various gravity field elements on or outside the geoid. Designed to advance gravity prospecting modeling and enhance gravity field data processing. This subsystem can support a wide array, including local terrain effects, terrain Bouguer effects, seawater Bouguer effects, crustal isostatic effects, terrain Helmert condensation effects, and residual terrain effects (RTE).

The subsystem computes effects on the following gravity field elements: geopotential, disturbing potential and height anomaly, gravity, gravity disturbance and gravity anomaly, vertical deflection vector, and gravity gradient tensors. The framework can support high-precision computations for elements located on or outside the geoid, ensuring seamless modeling continuity from the geoidal surface to satellite altitudes.

[Theoretical Basis]

For the normal gravity field, serving as the conventional reference datum for the anomalous gravity field, there is no issue of terrain mass influence. Consequently: (a) The terrain effects on gravity, gravity disturbance, and gravity anomaly are identical at any given point. (b) Similarly, the terrain effects on geopotential and disturbing potential are equivalent. (c) Likewise, the terrain effects on gravity gradient and disturbing gravity gradient are consistent.

[Validation & Performance Analysis]

To validate and analyze the performance of these algorithms, the test of the software suite employs terrain data from representative rugged mountainous regions, characterized by a mean elevation of approximately 4,000 meters and topographic relief exceeding 3,000 meters. These tests facilitate a comprehensive understanding of various terrain effect characteristics.