Experimental Physical Oceanography


 


RedSox Bill Johns
Hartmut Peters

in collaboration with

Amy Bower and
Dave Fratantoni
(Woods Hole Oceanographic)
The "Red Sea Outflow Experiment" (REDSOX) is to investigate the saline outflow from the Red Sea in the Gulf of Aden over a wide range of scales from small-scale turbulence to the pathways of Red Sea water on its way into the Indian Ocean.  Principal investigators are Bill Johns and Hartmut Peters (RSMAS/UM) and Amy Bower and Dave Fratantoni (WHOI).  The first cruise one the R/V "Knorr" took place from February 5 to March 15, 2001.  Our operations were very successful as detailed in the REDSOX-1 Cruise Report.  The second cruise on the R/V "Maurice Ewing" lasted from August 19 to September 12, 2001, the day after the terror attack on the United States of Sept. 11, 2001.  Prior to this event, we had our own experience with political volatility in parts of the world as reported in Nature of 13-Sep-01.  (The "Ewing" was attacked presumably by militiamen from northern Somalia.)  The REDSOX-2 cruise report details our observations.

To date, Amy Bower has been working on the far field data and the equilibration of the outflow plume at the Tadjura Rift.  Bill Johns has been working on TS and other general properties of the near field plume.  Silvia Matt wrote her M.S. thesis about the plume transports. Finally, Hartmut Peters has been focusing on the turbulent mixing in the descending Red Sea plume.

Within the turbulence and mixing component of RedSox, we repeatedly deployed a five-head acoustic Doppler current profiler on the sea floor in order to measure the Reynolds stress at 5-40 m above the bottom.  The entrainment on the upper edge of the plume can be estimated by observing the overturning in the water column, i.e. by measuring smallscale instabilities in the density profile.  The interfacial mixing turned out to be unexpectedly energetic with 20-m overturns and eddy diffusivities of the order of 10^-2 m^2/s, very large values for oceanic settings.  The turbulence studies are embedded in investigations of the momentum and mass budgets of the descending plume and of the general spreading of Red Sea water in the Gulf of Aden.

Results: Bower et al. (2002),  Peters et al. (2005), Peters and Johns (2005), Bower et al. (2005), Peters and Johns (2006), Fratantoni et al. (2006), Özgökmen et al. (2002). Funded by the National Science Foundation.


  R/V Knorr in the Gulf of Aden, REDSOX-1

Redsox-1 cruise picture  REDSOX-1, R/V Knorr, Victoria, Seychelles

Redsox-2 pirates  The "pirates" brandishing their RPG, R/V Ewing, cruise REDSOX-2

The Knorr cruise, REDSOX-1, ended at the Seychelles in the Indian Ocean at 4ºS: