Data and code for "Modified Parker's method for gravitational forward and inverse modeling using general polyhedral models"

We propose a new modified Parker's method for efficient gravitational forward modeling and inversion using general polyhedral models. We have made several important modifications to the classical method, including: 1) The new method is now applicable to a general polyhedron represented by triangulated surface or tetrahedral mesh, and with arbitrarily variable 3D density distribution. 2) An optimal Fourier-domain sampling strategy is used to improve the numerical accuracy of the new algorithm significantly. 3) A simple and effective automatic layering technique is introduced to accelerate the convergence rate of Parker's method. The method is demonstrated using both synthetic and real polyhedral models, including a sphere model approximated by a polyhedron, two asteroids, a digital elevation model in the Himalaya region, and the Yucca Flat basin model in Nevada. The numerical results show that, compared with analytical solutions of polyhedral models in the space domain, the modified Parker's method can improve the computational efficiency by several orders of magnitude while obtaining almost the same simulation results. The difference is well below existing instrumentation error level. By embedding the new forward algorithm into an iterative process, it can be used for fast inversion of density interfaces. Our new method is suitable for the efficient modeling and inversion of gravitational potential, gravitational vector, and gravitational gradient tensor caused by polyhedral models with a large number of faces, representing geological abnormal bodies, asteroids, and single or multilayer density interface models with triangulated surfaces.本研究提出一种改进后的新型帕克（Parker）方法，用于实现通用多面体模型下的高效重力正演与反演。本研究对经典帕克方法作出多项重要改进，具体包括：1. 该方法可适配由三角剖分曲面或四面体网格表示的通用多面体，且支持任意变化的三维密度分布；2. 采用最优傅里叶域采样策略，显著提升了新算法的数值精度；3. 引入简洁高效的自动分层技术，加速了帕克方法的收敛速度。 本研究通过合成与真实多面体模型对该方法进行了验证，所涉模型包括多面体近似的球体模型、两颗小行星、喜马拉雅地区数字高程模型，以及美国内华达州尤卡平原盆地模型。数值试验结果表明，相较于空间域多面体模型的解析解，改进后的帕克方法可将计算效率提升数个数量级，同时模拟结果几乎与解析解一致，二者差值远低于现有仪器的误差阈值。 将该正演算法嵌入迭代流程后，可用于密度界面的快速反演。本方法适用于海量面多面体模型所产生的重力位、重力矢量及重力梯度张量的高效正演与反演，此类模型可代表地质异常体、小行星，以及带三角剖分曲面的单层或多层密度界面模型。