RRS James Cook Cruise 41, 05-21 Dec 2009. UK DIMES1 Cruise Report: Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean

• Main Author: Naveira Garabato, A.
• Format: Book
• Language: English
• Published: National Oceanography Centre 2010
• Subjects: Antarctic; Southern Ocean; The Antarctic; Drake Passage; Pacific; Antarc*
• Online Access: https://eprints.soton.ac.uk/167561/; https://eprints.soton.ac.uk/167561/1/nocscr056.pdf

The DIMES (Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean) research project seeks to test and, if necessary, redefine the present paradigm of Southern Ocean mixing by obtaining systematic measurements of mixing, upwelling and their underlying driving processes in two contrasting regimes of the Antarctic Circumpolar Current (ACC) - the Southeast Pacific and the Southwest Atlantic. The JC041 cruise is the second cruise of the DIMES experiment and the first conducted in a British vessel. Its primary goals are: (1) to deploy a cluster of six U.K. moorings in Drake Passage to investigate how the energetic mesoscale eddies of the ACC are dissipated, and how they interact with the regional internal wave field; and (2) to deploy four Florida State University (FSU) sound sources in the same area to track a large set of isopycnal RAFOS floats deployed elsewhere by our American collaborators. All work planned in the JC041 cruise was carried out successfully. The work commenced with deployment of the six U.K. moorings (one of which contained an FSU sound source) in a crosslike pattern centred near 56.012 S, 57.825 W, in northeastern Drake Passage. A CTD / LADCP station was occupied at the location of each mooring, and a CTD / LADCP tow-yo transect was conducted in the lee of a topographic feature at the centre of the U.K. mooring area. Subsequently, the three FSU sound source moorings were deployed at different locations further south in Drake Passage. At the most easterly of those locations and in another site in northern Drake Passage we conducted upper-ocean CTD / LADCP tow-yos to survey the submesoscale structure of interleaving features in the vicinity of the Polar Front. Finally, three profiling floats (two U.K. standard Argo floats, and one FSU Iridium Argo float with acoustics) were deployed at various locations near the western edge of Drake Passage.