RRS James Cook Cruise 29, 01 Nov-22 Dec 2008. SOFine cruise report: Southern Ocean Finestructure

• Main Author: Naveira Garabato, A.
• Format: Book
• Language: English
• Published: National Oceanography Centre 2009
• Subjects: Antarctic; Kerguelen; Southern Ocean; The Antarctic; Antarc*
• Online Access: https://eprints.soton.ac.uk/65884/; https://eprints.soton.ac.uk/65884/1/nocscr035.pdf

The SOFINE research project aims to investigate two important, inter-related aspects of the physics of the Antarctic Circumpolar Current (ACC) and the Southern Ocean overturning circulation: (a) the ‘frictional’ processes that slow down the ACC as it meanders around major bathymetric obstacles and flows over small-scale topographic roughness; and (b) the meso- and small-scale phenomena that move water masses across the ACC and modify their properties in the process. These issues will be studied using a collection of data gathered during cruise JC 29, which is described in this report. The JC 29 cruise consisted primarily of a series of transects across the standing meander that the ACC forms around the northern edge of the Kerguelen Plateau. The transects delineate a double box (Fig. 2), with the outer transects sampling the ACC as it enters and exits the meander, and the inner transect surveying the current in an area within the meander and downstream of some complex small-scale topography. During the transects, hydrographic, velocity and microstructure profiles were obtained with a CTD, lowered ADCP and VMP-5500 (a free-fall vertical microstructure profiler) suite, and quasi-continuous measurements of upperocean currents and high-resolution bathymetry were made with vessel-mounted ADCPs and a multibeam system. A variety of profiling floats (including EM-APEX, Iridium and standard Argo units) were also deployed at the upstream end of the meander, with the goal of obtaining measurements of the downstream evolution of water mass properties and both thermohaline and shear finestructure. Opportunistic measurements of upper-ocean turbulence were obtained with an ISW tethered turbulence profiler. Finally, a cluster of three short-term (2.5 weeks) moorings and two long-term (> 1 year) moorings were deployed at the southern end of the inner transect to measure the generation of internal waves by flow-topography interaction at a small ridge and the mesoscale eddy statistics of the area, respectively. The short-term ...