Title: THOR: A New and Flexible Global Circulation Model to Explore Planetary Atmospheres Show Chinese title

Title: THOR：一种新的和灵活的全球环流模型，用于探索行星大气层

Abstract: We have designed and developed, from scratch, a global circulation model named THOR that solves the three-dimensional non-hydrostatic Euler equations. Our general approach lifts the commonly used assumptions of a shallow atmosphere and hydrostatic equilibrium. We solve the "pole problem" (where converging meridians on a sphere lead to increasingly smaller time steps near the poles) by implementing an icosahedral grid. Irregularities in the grid, which lead to grid imprinting, are smoothed using the "spring dynamics" technique. We validate our implementation of spring dynamics by examining calculations of the divergence and gradient of test functions. To prevent the computational time step from being bottlenecked by having to resolve sound waves, we implement a split-explicit method together with a horizontally explicit and vertically implicit integration. We validate our global circulation model by reproducing the Earth and also the hot Jupiter-like benchmark tests. THOR was designed to run on Graphics Processing Units (GPUs), which allows for physics modules (radiative transfer, clouds, chemistry) to be added in the future, and is part of the open-source Exoclimes Simulation Platform (ESP; www.exoclime.org). Show Chinese abstract

Abstract: 我们从零开始设计和开发了一个名为THOR的全球环流模型，该模型求解三维非静力欧拉方程。 我们的总体方法摒弃了常用的浅大气层和静力平衡假设。 我们通过实现二十面体网格来解决“极点问题”（球面上汇聚的经线会导致极点附近的时间步长越来越小）。 通过“弹簧动力学”技术对导致网格印记的网格不规则性进行平滑处理。 我们通过检查测试函数的散度和梯度计算来验证弹簧动力学的实现。 为了防止计算时间步长因必须解析声波而成为瓶颈，我们结合使用了分裂显式方法以及水平显式和垂直隐式积分。 我们通过再现地球和热木星类基准测试来验证我们的全球环流模型。 THOR设计用于在图形处理单元（GPU）上运行，这使得未来可以添加物理模块（辐射传输、云、化学），并且是开源Exoclimes Simulation Platform（ESP；www.exoclime.org）的一部分。