Scientific Computation Platform for Geophysical Geodesy

Computation demo for the terrain effect and gravity prospecting model

Issuing time:2024-11-11 16:27Author:Chuanyin ZhangLink:http://www.zcyphygeodesy.com/en/
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From the Earth geopotential coefficient model and land-sea terrain model, the classical Bouguer gravity anomaly (disturbance) and isostatic gravity anomaly (disturbance) are calculated synchronously in four steps in any region of the world to demonstrate the fast and convenient computation process of the land-sea unified classical Bouguer / isostatic anomaly.

From the ground digital elevation model and discrete observed gravity disturbance calculated from EGM2008 geopotential model, a remove-restore scheme with the residual terrain effects employed, calculate the complete Bouguer gravity disturbance grid on an equipotential surface which is also the observation reduction surface, to show the basic computation scheme and process of the land-sea unified complete Bouguer effects on various gravity field elements near-Earth space.

Computation scheme of gravity prospecting modelling is introduced by analytic fusion of heterogeneous observations.

The complete Bouguer effect is defined as the variation of Earth gravity field because of the terrain mass above the geoid removed and the seawater density compensated to the terrain density.

PAGravf4.5 has the high-precision analytical computation capacity of various terrain effects on any type of field element. At the same time, it can model analytically the all-element gravity field in whole space outside geoid from various heterogeneous observations. The combination of the two can effectively solve the trouble of gravity prospecting modelling that can deeply fuse all the gravity field information in multi-source heterogeneous observations.

In any region of the world, you can accurately calculate the land-sea unified complete Bouguer gravity anomaly (disturbance), complete Bouguer vertical deflection, complete Bouguer gravity gradient, and classical Bouguer / isostatic gravity anomaly (disturbance) from heterogeneous observations such as gravity, gravity gradient, satellite altimetry, (astronomical) vertical deflection, GNSS-leveling etc. in the different altitudes, cross-distribution and land-sea coexisting cases.

The general computation process for fine gravity prospecting from heterogeneous observations is as follows.

(1) Select the calculation area, target calculation surface (terrain equiheight surface is recommended here) for gravity prospecting modelling and obtain (or collect) all the gravity field and geodetic observations as much as possible.

(2) Call the related programs in the subsystem [Precision approach and all-element modelling on Earth gravity field] to determine the high-resolution grid of gravity field elements corresponding to the target prospecting model on the calculation surface.

(3) Call the related programs in the subsystem [Computation of various terrain effects on various field elements outside geoid] to determine the terrain effect grid on field element corresponding to the target prospecting model on the calculation surface.

(4) By subtracting the terrain effect grid from the gravity field element grid directly, you can obtain the target gravity prospecting model which have deeply fuse all the gravity field information in heterogeneous observations.

The computation of gravity prospecting modelling with the analytic relations of gravity field as the constraints by PAGravf4.5 can deeply fuse all the gravity field information from heterogeneous observations in the different altitudes, cross-distribution and land-sea coexisting cases, whose observation mode can be on terrestrial, marine, aviation and satellite.




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