Remote-sensing study on meso-scale mixing processes off San Onofre nuclear generating station

Turbulent energy in the ocean which is manifest in the form of mesoscale eddies and gyres, has been receiving increasing attention in recent years. In the deep ocean, away from the land boundary, these meso-scale eddies typically measure 100-200 km in diameter and exhibit a persistence life scale of up to several months. On the other hand, eddies which have been recognized close to the coast exhibit typical sizes of around 50 km or less and a persistence scale of the order of weeks. Drogue trajectories and circulation deduced from satellite imagery in the Southern California Bight, illustrating typical examples of coastal meso-scale eddies are shown. Sudden quantum changes in sea water temperature being witnessed in the temperature records off San Onofre Nuclear Generating Station, may be at least in part attributed to the advection of such eddies. For the purpose of investigating possible effects of these little recognized coastal meso-scale eddies on the thermal-discharge environment, the authors have studied a sequence of TIROS-N thermal imagery, plus historical coastal temperature data from National Ocean Survey stations and own recording stations. The TIROS-N imagery were enhanced through histogram hyperbolization procedures. Coastal meso-scale eddies which were identified on TIROS-N imagery exhibited divers types: free advective eddies, wakes (captive eddies), and organized eddies such as those in a von Karman vortex street downdrift of an island or cape