Characterization of mesoscale eddies and detection of submesoscale eddies derived from satellite imagery and HF radar off the coast of southwestern Puerto Rico

Coherent sub-mesoscale features such as spiral eddies are known to be ubiquitous in the world's oceans. Yet, due to their complex geometry, they are often difficult to characterize. Sub-mesoscale ocean dynamics with characteristic dimensions on the order of kilometers have been found to play a major role in upper ocean stirring and mixing. Manifestations of these structures all around the Caribbean Coastal Ocean Observing System (CariCOOS) region have been found to influence coastal and oceanic waters impacting upper ocean hydrodynamics and biogeochemistry. CariCOOS modeling efforts in the region have yet to produce reliable forecasts of near coastal ocean dynamics. Owing to the growing demand for coastal ocean models yielding accurate forecast, CariCOOS has proposed the operational deployment of a 1/100 degree Regional Ocean Modelling System (ROMS) nested in the 1/36 degree resolution Navy Coastal Ocean Model (AMSEAS) which itself is nested in the Hybrid Coordinate Ocean Model (HYCOM), a global 1/12 degree data-assimilative hybrid isopycnal-sigma-pressure coordinates forecast system. Although the progression has been consistent, results urge the identification of possible skill performance constraints and phenomenological limitations. An inward approach has been adopted to assess the output of parent models versus observations from satellites, drifters, gliders, sea level measurements, buoys, and HF radars. Part of the adopted approach focuses on the characterization and daily-based detection of sub-mesoscale ocean dynamic features. CariCOOS observational assets and satellite imagery brings forth the ability to characterize quasi-permanent (or periodical) phenomena close to the coast. Thanks to the recent expansion of the CariCOOS High-Frequency (HF) radar network consisting of two long range (5 MHz) antennas on the southwestern coast of Puerto Rico, unprecedented spatial and temporal coverage will be available for this two-part study. For the first part, historical satellite altimetry, as well as other discrete observations, will be used to characterize the quasi-geostrophic mesoscale eddy signatures near the southwestern coast of Puerto Rico. On the second part, satellite imagery and HF radar capabilities to capture sub-mesoscale eddy phenomena will be assessed with the objective of implementing coherent structure detection algorithm based on a vector geometry method. A comparison between detected sub-mesoscale eddies with HF radars and available operational models (AMSEAS & HYCOM) will be qualitatively assessed.