Development of a high-resolution coupled SHiELD-MOM6 model – Part 1: Model overview, coupling technique, and validation in a regional setup Geoscientific Model Development

We present a new high-resolution coupled atmosphere–ocean model, SHiELD-MOM6, which integrates the Geophysical Fluid Dynamics Laboratory (GFDL) advanced atmospheric model, the System for High-resolution modeling for Earth-to-Local Domains (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 the SHiELD physics parameterization 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 of 2024. By analyzing the storm intensity, its structure, and its effects on the ocean phenomena such as the upwelling and sea-level changes, the results reveal that air–sea interactions are effectively captured. Scalability tests further confirm the model's computational efficiency. This work established a unified modular cornerstone for advancing high-resolution coupled modeling with significant implications for weather forecasting and climate research. Grant no. NA18OAR4320123 Grant no. NA23OAR4320198 Grant no. NA23OAR4050432I