ABSTRACT

Exploration for and production of hydrocarbons from deep water of the northern Gulf's continental slope requires specific information on slope-depth physical oceanographic processes for environmental and operational applications. Few long-term records of slope currents exist in the open literature. In an effort to fill this gap in knowledge, a year-long current meter mooring was deployed off the central Louisiana coast in 600 m (1800 ft) of water. The current meter was situated approximately 10 m (30 ft) above the bottom. Tidal currents modulated a mean offshore flow.

Some suggestion of topographic steering is present in the record. The principal axes of the raw data and the low-passed data are not coincident. Bursts of strong current activity are associated with significant variability in the associated thermal signal. The periods of strong variability are slightly longer than one week. These periodic current bursts do not appear to be characteristic of any natural oscillation of the Gulf of Mexico. The current activity is probably associated with meso-scale eddies typically found along the shelf break and upper slope.

While important for the long-term transport of suspended materials and the alteration of thermal structure at these depths, the observed currents were, typically, of insufficient strength to resuspend sediment. However, direct Loop Current intrusions and associated eddies have the capacity to resuspend and transport sediment. Such currents were not measured during the deployment of our mooring.