To improve our understanding of continental shelf processes there exists a need for feature extraction techniques to identify patterns of variability from long surface current image time series so that the underlying physics can be assessed. 1996 Paduan and Rosenfeld 1996 Beckenbach and Washburn 2004 Chant et al. High frequency (HF) radars are finding increasing applications for the sampling of surface current patterns at high spatial and temporal resolution (e.g., Barrick 1977 Gurgel et al. The SOM is shown to be a useful technique for extracting ocean current patterns with dynamically distinctive spatial and temporal structures sampled by HF radar and supporting in situ measurements. The currents in the subtidal frequency band are stronger and with more complex patterns consistent with wind and buoyancy forcing. The currents in the diurnal band are less homogeneous, more baroclinic, and clockwise polarized, consistent with a combination of diurnal tides and near-inertial oscillations. The currents in the semidiurnal band are relatively homogeneous in space, barotropic, clockwise polarized, and have a neap-spring modulation consistent with semidiurnal tides. Three separate ocean–atmosphere frequency bands are considered: semidiurnal, diurnal, and subtidal. To assess the spatial structures and temporal evolutions of distinct physical processes on the West Florida Shelf, patterns of ocean current variability are extracted from a joint HF radar and ADCP dataset acquired from August to September 2003 using Self-Organizing Map (SOM) analyses.
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