A description of the seasonal thermocline cycle in shallow coastal water

Abstract

Details of the annual thermocline cycle in the coastal area off San Diego have been determined from temperature data recorded hourly for over a year at the Naval Undersea Research and Development Center Oceanographic Tower. Vertical thermal gradients averaged 0.59°C/m at their strongest part from late April through early September. The sharpest gradients, which occurred in late June, were as great as 1.27°C/m. Transient gradients averaging 0.29°C/m at their strongest part occurred frequently in late March and early April and from late September through early November. Weak thermal gradients averaging 0.15°C/m at their sharpest predominated from late November through early March. Water temperature varied from 9.7° to 23.6°C. Internal tides persisted throughout the year, contributing to monthly temperature variances that ranged from 0.2 (°C)2 in January to 5.6 (°C)2 in May and August.