The topographic bias (TB) is defined as the difference between the disturbing potential on the geoid and the harmonic downward continued one. Sjöberg (J Geoid 81:345–350, 2007, 10.1007/s00190-006-0112-2SearchinGoogleScholar; Geophys J Int 176:14–18, 2009) showed that the TB is that of a Bouguer plate, and the terrain contribution is zero. Out of curiosity, we inspected the TB of a homogeneous right circular cylinder and a cone—the terrain correction is zero for the cylinder, and it reaches the maximum for the cone at the top center points. As expected, the TB of the cylinder is the same as a Bouguer plate of the same height, and it is independent of the base size. The TB of the cone is quite different, it is not equal to that of a Bouguer plate with the same height of the cone; rather, it is a function of the shape of the cone or the ratio of its base radius to the height. The TB becomes smaller with a steeper slope of the slant height of the cone, and it approaches the TB of the Bouguer plate with a gentle slope of the slant height. For a cone with the same height and base radius, the relative error of ignoring the terrain reaches 80%. The TB of the cone disproves that the TB of the terrain is zero.

地形偏差 (TB) 定义为大地水准面上的干扰电势与谐波向下连续电势之间的差值。 Sjöberg (J Geoid 81:345–350, 2007, 10.1007/s00190-006-0112-2SearchinGoogleScholar; Geophys J Int 176:14–18, 2009)表明TB是布格板块，地形贡献为零。出于好奇，我们检查了均质直圆柱体和圆锥体的 TB——圆柱体的地形修正为零，而圆锥体的地形修正在顶部中心点达到最大值。正如预期的那样，圆柱体的 TB 与相同高度的布格板相同，并且与底座尺寸无关。锥体的TB有很大不同，它不等于相同锥体高度的布格板；相反，它是圆锥形状或其底半径与高度之比的函数。锥体斜高斜率越陡，TB越小，斜高斜率越平缓，越接近布格板TB。对于相同高度和底半径的圆锥体，忽略地形的相对误差达到80%。圆锥体的 TB 反驳了地形的 TB 为零。