3 Jun 2025

Development of a Wave Model Component in the First Coupled Global Ensemble Forecast System at NOAA

Abstract: We describe the development of the wave component in the first global-scale coupled operational forecast system using the Unified Forecasting System at NOAA, part of the U.S. National Weather Service operational forecasting suite. The operational implementation of the atmosphere–wave coupled Global Ensemble Forecast System, version 12, was a critical step in NOAA’s transition to the broader community-based UFS framework. GEFSv12 represents a significant advancement, extending forecast ranges and empowering the NWS to deliver advanced weather predictions with extended lead times for high-impact events. The integration of a coupled wave component with higher spatial and temporal resolution and optimized physics parameterizations enhanced forecast skill and predictability, particularly benefiting winter storm predictions of wave heights and peak wave periods. This endeavor encountered challenges addressed by the simultaneous development of new features that enhanced wave model forecast skill and product quality and facilitated by a team collaborating with NOAA’s operational forecasting centers. The GEFSv12 upgrade marks a pivotal shift in NOAA’s global forecasting capabilities, setting a new standard in wave prediction. We also describe the coupled GEFSv12-Wave component impacts on NOAA operational forecasts and ongoing experimental enhancements, which represent a substantial contribution to NOAA’s transition to the fully coupled UFS framework.

3 Jun 2025

Wind Forcing, Source Term and Grid Optimization for Hurricane Wave Modelling in the Gulf of Mexico

Abstract: This study evaluates the performance of WAVEWATCH III model driven by different wind forcing products and behavior of different parameterizations of the model’s source terms controlling energy input and dissipation and quadruplet wave-wave interactions during Hurricane Ida. We also compare the performance of the model configured on uniform unstructured and conventional non-uniform unstructured grids. Key findings show ECMWF-forecast and HRRR out-performed other products in capturing wind speeds relative to buoys, satellite and the revised Atlantic hurricane database observations. However, all products underestimated wind speeds above 20 m/s, with ECMWF and HRRR occasionally performing better for most wind speed values above 35 m/s relative to observations. The corresponding wave simulation results indicated Ida’s wave fields were better captured by model simulations with ECMWF and HRRR wind products, with biases of 2% against buoys in the Gulf of Mexico and 6% and 3% respectively against satellite data. We also highlighted limitations in bulk wave analysis by computing partial Hs and 1D spectra density differences between model and buoy for selected source terms. This reveals consistent overestimation at the lowest frequency bin and underestimation of the three higher frequency bins with a mix of negative and positive energy density difference across different frequencies.

2 Jun 2025

Future Coastal Tundra Loss due to Compounding Environmental Changes in Alaska

Abstract: Anthropogenic climate change is amplified in the Arctic, where less sea ice enables energetic wave climates while higher air and soil temperatures increase tundra erodibility. These changes are likely to exacerbate retreat of coastal tundra yet remain poorly constrained on timescales relevant to storm wave impacts. A stochastic weather generator is used to create 1,000 synthetic hourly time series of waves, water levels, offshore sea ice concentration, and air temperatures used as forcing for an efficient coastal tundra model. The ensemble set of morphological change simulations provides a probabilistic perspective on the range of tundra retreats and the relative effects of each environmental forcing. Ensembles show as the depth of the erodible layer increases, the style of tundra retreat shifts from a consistent recession to intermittent events with large magnitudes and a factor 2 range in outcomes. Model scenarios highlight shallower thaw depths narrows the range of retreats and reduces individual extreme events, but a dynamic feedback between beach slopes, wave runup, and thermally limited erosion volumes ultimately increases the number of storm events associated with retreat. The minimum tundra retreat is governed by background shoreline change and the specifics of the topographic profile dominate underlying changes in the future wave climate statistics and open water season. As the Arctic continues to warm, the change in retreat style will have significant ramifications for coastal resilience.

2 Jun 2025

Miami Harbor Entrance Channel Improvements Study: Ship Simulation Report

Abstract: The US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory (ERDC-CHL), Ship/Tow Simulator (STS) was used to perform a navigation study assisting the US Army Corps of Engineers (USACE), Jacksonville District. The study evaluates additional navigation channel modifications from the previous 2019 study to allow larger containerships to call at the Port of Miami. This study was conducted at the CHL real-time STS. Real-time refers to the fact that model time uses a 1:1 ratio to prototype time. In addition, real-world environmental forces were simulated and acted upon the modeled ships during the study. These forces included currents, wind, bathymetry, and bank effects. Simulations for the proposed modifications were conducted at CHL for 1 week in August 2023. Four Biscayne Bay pilots participated in the validation and testing exercises. The design vessels include the MSC Daniela (14,000 twenty-foot equivalent unit [TEU]) container ship and the Maersk Guayaquil (12,000 TEU) container ship. Simulation results are presented in the form of track plots and pilot questionnaires, which were reviewed to develop the conclusions and recommendations.