An Investigation of Summer Upwelling Across Central Florida's Atlantic Coast: The Case for Wind Stress Forcing

Abstract

Three water temperature time series are used to characterize seasonal upwelling off Florida's central Atlantic coast. Data recorded near the bottom at a mid-shelf study site indicate fluctuations in temperature of 4-8 °C, probably representing upwelling intrusions, occurring over time scales on the order of several days to about a week during May, June and early July of 1986. During the same time period, data from two inner-shelf study sites show a relatively steady seasonal rise in temperature with little indication of upwelling. A major upwelling event, beginning in mid -July and lasting approximately three weeks, appears in all three records. At the mid-shelf site, the event is characterized by an abrupt decrease of nearly 12°C followed by a gradual recovery period. Over the inner shelf, temperature decreases more slowly and returns relatively rapidly to values characteristic of the summer season. Calculations indicate that upwelled water moves along and across the shelf to the northwest at 10-13 cm sec^-1. Meteorological data indicate that wind plays a significant role in driving the observed upwelling.