Enhancing the Capabilities of the UFS Coastal Application: a Comprehensive Evaluation and Benchmarking of Hydrodynamics

The Unified Forecast System (UFS) is an emerging framework designed to meet the requirements of coastal modeling applications for NOAA within the UFS Weather Model framework. However, the current UFS framework lacks the integration of key variables essential for accurately capturing oceanic processes across multiple scales, limiting its ability to be tested against real-world data. This study addresses these gaps by expanding the UFS Coastal application to include a broader range of forcing variables such as air temperature, specific humidity, solar radiation, and river discharge, which are vital for simulating complex coastal dynamics.

We developed a detailed hydrodynamic model using the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM) for the New York Harbor area, employing detailed domain discretization and forcing it with High-Resolution Rapid Refresh (HRRR) atmospheric data and TPXO tidal data. The model was validated against a comprehensive set of observational data, including water elevation, temperature, salinity, and velocity, for the year 2021, encompassing significant weather events such as Hurricanes Elsa, Henri, and Ida. In parallel, we enhanced the UFS Coastal application by modifying its source code to accommodate the same range of forcing variables used in the SCHISM model.

To assess the performance of the UFS Coastal application, we conducted a rigorous benchmarking process against the stand-alone SCHISM model, utilizing metrics such as root mean square error (RMSE) and bias when compared to observational data from New York Harbor. This analysis revealed that the enhanced UFS Coastal application can achieve accuracy comparable to that of the stand-alone SCHISM model, particularly in replicating the complex hydrodynamics of the harbor.

The findings underscore the potential of UFS Coastal to serve as a robust and reliable tool for coastal modeling, offering valuable insights for navigation, environmental prediction, and risk management within coastal zones. Future work will focus on further refining the model’s capabilities, including the integration of more complex coupling mechanisms and exploring its application in diverse coastal regions. This benchmarking effort marks an important step forward in the operational readiness and application scope of UFS Coastal.