Predicting ocean circulation on small- to sub-mesoscales in a strong western boundary current using a three-dimensional nonhydrostatic ocean model

Understanding and predicting ocean circulation on small- to sub-mesoscales and mesoscales remains challenging, partly because ocean circulation models typically have a minimum horizontal resolution of 1 km.Modeling oceancirculation on small- to sub-mesoscales is essential to characterizing ocean dynamics in highly energetic areas such as western boundary currents. Traditional ocean models are also hydrostatic. Nonhydrostatic models are significantly more computationally expensive and difficult to implement on climate scales. Nevertheless, they provide a more accurate, three-dimensional simulation. In this work we propose a new approach to address these challenges. A high-resolution, three-dimensional computational fluid dynamics model was developed and verified with field data from the Straits of Florida. For model verification, a six ADCP mooring array in a rectangular shape was deployed ~12.9 km offshore on the Miami Terrace. The data from five ADCP moorings were used to produce inlet boundary conditions, which were updated every 1 minute. The sixth ADCP in the center of the outlet was used for model verification. This approach demonstrates reasonably good predictive ability on sub-mesoscales in a strong western boundary current. We anticipate our work to be a starting point for ocean prediction models applicable to western boundary currents (i.e., Florida Current, Kuroshio Current, and Agulhas Current)in the range from small scales to sub-mesoscales, based on advanced data assimilation techniques. According to the US Climate Variability and Predictability (CLIVAR) program, oceanic mesoscales and sub-mesoscales have relevance to climate, providing a coupled oceanographic-atmospheric framework, which is important for studying processes on climate scales.
The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)