The Helmert’s second condensation method is usually used to condense the topographical masses outside the boundary surface in the determination of the geoid and quasi-geoid based on the boundary-value theory. The condensation of topographical masses produces direct and indirect topographical effects. Nowadays, the Remove-Compute-Restore (RCR) technique has been widely utilized in the boundary-value problems. In view of spectral consistency, high-frequency direct and indirect topographical effects should be used in the Hotine-Helmert/Stokes–Helmert integral when the Earth gravitational model serves as the reference model in determining the (quasi-) geoid. Thus, the algorithms for high-frequency topographical effects are investigated in this manuscript. First, the prism methods for near-zone direct and indirect topographical effects are derived to improve the accuracies of near-zone effects compared with the traditional surface integral methods. Second, the Molodenskii spectral methods truncated to power H⁴ are put forward for far-zone topographical effects. Next, the "prism + Molodenskii spectral-spherical harmonic" combined algorithms for high-frequency topographical effects are further presented. At last, the effectiveness of the combined algorithms for the high-frequency topographical effects are verified in a mountainous test area.

基于边值理论确定大地水准面和准大地水准面时，通常采用赫尔默特第二凝聚法对边界面外的地形体进行凝聚。地形体的凝结产生直接和间接的地形效应。目前，删除-计算-恢复（RCR）技术已广泛应用于边值问题中。考虑到频谱一致性，当地球引力模型作为确定（准）大地水准面的参考模型时，Hotine-Helmert/Stokes-Helmert积分中应使用高频直接和间接地形效应。因此，本手稿研究了高频地形效应的算法。首先，推导了近区直接和间接地形效应的棱镜方法，与传统的表面积分方法相比，提高了近区效应的精度。其次，针对远区地形效应，提出了截断为H ⁴ 次方的Molodenskii谱方法。接下来，进一步提出了高频地形效应的“棱镜+莫洛登斯基谱球谐”组合算法。最后，在山区试验区验证了组合算法对于高频地形效应的有效性。