Earth system models are complex integrated models of atmosphere, ocean, sea ice, and land surface. Coupling the components can be a significant challenge due to the difference in physics, temporal, and spatial scales. This study explores new coupling strategies for the fluid-fluid interaction problem based on multirate partitioned Runge-Kutta methods. We consider compressible Navier-Stokes equations with gravity coupled through a rigid-lid interface. Our large-scale numerical experiments reveal that multirate partitioned Runge-Kutta coupling schemes (1) can conserve total mass; (2) have second-order accuracy in time; and (3) provide favorable strong- and weak-scaling performance on modern computing architectures. We also show that the speedup factors of multirate partitioned Runge-Kutta methods match theoretical expectations over their base (single-rate) method.

翻译：地球系统模型是包含大气、海洋、海冰和陆地表面的复杂集成模型。由于各组件在物理特性、时间尺度和空间尺度上的差异，其耦合过程面临重大挑战。本研究基于多速率分区龙格-库塔方法，探索了流体-流体相互作用问题的新型耦合策略。我们考虑了通过刚性盖界面耦合的含重力可压缩纳维-斯托克斯方程组。大规模数值实验表明，多速率分区龙格-库塔耦合格式：(1) 能守恒总质量；(2) 具备时间二阶精度；(3) 在现代计算架构上表现出优异的强扩展性与弱扩展性。我们还证明，多速率分区龙格-库塔方法的加速比因子与基准（单速率）方法的理论预期相符。