Gravity forward modeling provides important high-resolution information for the development of global gravity models, and can also be applied in many studies, e.g., topographic/isostatic effects computation and Bouguer anomaly maps compilation. In this paper, we present efficient spectral forward modeling approaches in the spheroidal harmonic domain, based on a single layer with constant density or volumetric layers with laterally varying density. With the binomial series expansion applied in spheroidal harmonic gravity forward modeling, the computational cost of these approaches is much lower than similar approaches. In both layering cases, we derive topographic potential models up to degree and order (d/o) 2190 by applying the approaches proposed here. Our methodology is evaluated by comparing these outcome models with other similar topographic potential models derived from spherical harmonic solutions. We find that topographic potentials from spheroidal and spherical harmonic approaches are in great agreement. Finally, the model named EHFM_Earth_7200 with a maximum degree of 7200 was derived by a layer-based approach. The evaluations by ground-truth data show that EHFM_Earth_7200 improves GO_CONS_GCF_2_DIR_R6 by 4% over Antarctica, and improves EGM2008 by ~ 34% over northern Canada. A global map of Bouguer gravity anomaly was also compiled with EHFM_Earth_7200 and EGM2008. As the main conclusion of this work, the new model EHFM_Earth_7200 is beneficial for investigating and modeling the Earth’s external gravity field, the new approaches have comparable accuracy to spherical harmonic approaches and are more suitable for practical use with guaranteed convergence regions because they are performed in the spheroidal harmonic domain.

重力正演建模为全球重力模型的开发提供了重要的高分辨率信息，也可以应用于许多研究，例如地形/等静压效应计算和 Bouguer 异常图编译。在本文中，我们提出了球谐域中高效的频谱正演建模方法，该方法基于具有恒定密度的单层或具有横向变化密度的体积层。通过在球谐引力前向建模中应用二项式级数展开，这些方法的计算成本远低于同类方法。在这两种分层情况下，我们通过应用这里提出的方法推导出了高达 2190 阶 （d/o） 的地形势模型。我们的方法是将这些结果模型与源自球谐解的其他类似地形势模型进行比较来评估的。我们发现球面和球谐方法的地形势非常一致。最后，通过基于层的方法推导了名为 EHFM_Earth_7200 的模型，最大度数为 7200。地面实况数据的评估表明，EHFM_Earth_7200 南极洲的GO_CONS_GCF_2_DIR_R6提高了 4%，加拿大北部的EGM2008提高了 ~ 34%。还用 EHFM_Earth_7200 和 EGM2008 编制了布格重力异常的全球地图。作为这项工作的主要结论，新模型EHFM_Earth_7200有利于研究和模拟地球的外重力场，新方法具有与球谐方法相当的精度，并且更适合在保证收敛区域的实际应用，因为它们是在球谐域中进行的。