Development of a High-Resolution Coupled SHiELD-MOM6 Model. Part I – Model Overview, Coupling Technique, and Validation in a Regional Setup

Abstract. We present a new high-resolution coupled atmosphere-ocean model, SHiELD-MOM6, which integrates GFDL's advanced atmospheric model, System for High-resolution modeling for Earth-to-Local Domain (SHiELD), the Modular Ocean Model version 6 (MOM6), and the Sea Ice Simulator (SIS2). The model leverages the Flexible Modeling System (FMS) coupler and its innovative exchange grid to enable a robust and scalable two-way interaction between the atmosphere and ocean. The atmospheric component is built on the non-hydrostatic Finite-Volume Cubed-Sphere Dynamical Core (FV3) with the latest version of SHiELD physics parametrization suite, while the ocean component is the latest version of MOM supporting kilometer-scale high-resolution and regional applications. Validation of this new coupled model is demonstrated through a suite of experiments, including idealized hurricane simulations and a realistic North Atlantic case study featuring Hurricane Helene 2024. The results reveal that air-sea interactions are effectively captured, by analyzing the storm intensity, structure and its effects on the ocean phenomena such as the upwelling and sea level changes. Scalability tests further confirms the model's computational efficiency. This work established a unified modular cornerstone for advancing high-resolution coupled modeling with significant implication for weather forecasting and climate research.