Turbulence and waves over irregularly sloping topography : cruise report - Oceanus 324

Abstract

This report documents the work of R/V Oceanus cruise 324, which occurred during May of 1998. This cruise was the field component of the Turbulence and Waves in Irregularly Sloping Topography (TWIST) program. TWIST was part of the Littoral Internal Wave Initiative (LIW) supported by the Office of Naval Research. The objective of TWIST was to sample the background, internal wave and turbulence properties on the Continental Slope in the Mid-Atlantic Bight. Previous investigations have revealed strongly enhanced finescale internal wavefields and much more energetic turbulence due to internal wave breaking above topographic roughness associated with the Mid-Atlantic Ridge. So, an area of steeply sloping ridges and troughs running perpendicular to the continental slope near 36˚34'N, 74˚39'W was chosen as the site of the observational program due to its topographic similarity to the Mid-Atlantic Ridge. Fíve instrument systems were employed to make observations during this cruise: the High Resolution Profier (HRP), three Moored Profiler (MP) moorings, a Lowered Acoustic Doppler Current Profiler/Conductivity, Temperature, Depth (LADCP/CTD) rosette, eXpendable Current Profilers/eXpendable CTD (XCP/XCTD), and finally, the shipboard ADCP. The data from these instruments (more than 1100 full depth profiles) provide adequate spatial and temporal resolution to describe the finescale and turbulent processes observed.