| Popis: |
The incomplete knowledge of the topographic density distribution causes a topographic bias in all gravimetric geoid determinations. This bias becomes critical in aiming for accurate geoid models in high mountainous regions. The bias can be divided into two components: the bias of the Bouguer shell (or Bouguer plate) and that of the remaining terrain. Starting from the known (disturbing) potential at the Earth’s surface, we study the possible location of the bias caused by incomplete reduction of the terrain masses in the computational process, We show that there is no such bias for terrain masses located exterior to the Bouguer plate/shell and/or inside the Bouguer plate at a lateral distance exceeding the height HP of the topography at the computational point. We conclude that the only possible terrain bias could be generated by masses inside a dome of height $$ \left(\sqrt{2}-1\right){H}_P $$ 2 − 1 H P centered along the radius vector through the computational point with its base of radius HP at sea-level. |
