High-Resolution MOM6 Coupling and Next Generation Hurricane Analysis and Forecast System

Coupling MOM6 to Hurricane Analysis and Forecast System (HAFS) is a part of an effort to build a next-generation HAFS. With the completion of merging MOM6 within the Unified Forecast System (UFS) framework, it allows diversity for the weather- and regional-scale application. Similar to the operational HAFS that couples HYbrid Coordinate Ocean Model (HYCOM), the feedback between the atmosphere model and MOM6 takes place through the Community Mediator for Earth Prediction Systems (CMEPS). Sensitivity study of Tropical Cyclone (TC) forecasts using these two systems showed little differences in the track and intensity forecasts. However, there were discernible differences. For instance, the storm structure showed cooler temperature anomalies located at lower altitude for MOM6 coupling, compared to the counterpart HYCOM coupling. Ocean simulations were also different, especially in the upper layer, where MOM6 predicted generally thicker mixed-layer depth and less unstable, even beneath the hurricane winds, than HYCOM. Detailed analysis, including the turbulence flux in the air-sea interface and the thermodynamic variability in the PBL will be reviewed in the presentation.