HF radar detects submesoscale spiral eddies in Monterey Bay

Shore based high-frequency Doppler radar observations are utilized for the reconstruction of high-resolution surface currents in Monterey Bay and off Monterey: meso-scale ageostrophic spiral eddies with scales equal to 10-20 km and lifetimes up to 6-12 hours. We have found that cyclonic spiral eddies are generated by the shear instability in the transition zone of the California coast. However, observed anticyclonic spiral eddies with smaller sizes and life times have explicit topographic nature. The spiraling order (So), Rossby (Ro) and Reynolds (Re_⊥) numbers for eddies were estimated to identify different stages of eddy evolution.