BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Pathways of boundary mixing in the Antarctic Circumpolar Current r
 evealed by a tracer release experiment. - Marie-Jose Messias\, University 
 of Exeter
DTSTART:20180523T100000Z
DTEND:20180523T110000Z
UID:TALK105805@talks.cam.ac.uk
CONTACT:Dr Emma Boland
DESCRIPTION:Diapycnal mixing  (across density surfaces) is a key process i
 n the Antarctic Circumpolar Current (ACC) said to control a third of the u
 pward transport of deep water towards the surface of the ocean overturning
  in the Southern Ocean. To shed light on the on going debate of pathways t
 o mixing in the Southern Ocean\, we present here the spatiotemporal patter
 ns of the mixing inferred from a tracer released at mid-depth upstream of 
 the topographic threshold of Drake Passage. The magnitude and distribution
 s of the mixing intensification are fund to be robust\, linked to flow vel
 ocity and topography: most notably\, a double intensification in the jets 
 cores and a two order of magnitude intensification from O(2×10-5) m2 s-1 
  above the smooth seafloor of the eastern Pacific\,  O(2×10-4) m2 s-1  wh
 ere the tracer  lies at 2-km depth  above the abyssal complex topography\,
  to O(2×10-3) m2 s-1 where the tracer encounters sloping topography along
  the ACC northern boundary (within Sub-Antarctic Front) and in the Falklan
 d Through. The evidence of intense near-boundary mixing suggest that diapy
 cnal mixing in the ACC is intrinsically 3-dimensional\, i.e. water gets mi
 xed mostly near isopycnal incrops and the products of boundary mixing dist
 ributed away from the boundary along sloping isopycnals. In that context\,
  we compare the vertical displacement of the tracer along sloping topograp
 hy with its displacement in a region of different dynamics (i.e Polar Fron
 t).  The tracer in the PF  appears to have migrated towards higher density
 \, giving a diapycnal downwelling  O(0.025kg/m3).
LOCATION:British Antarctic Survey\, Innovation Centre\, Seminar Room 1
END:VEVENT
END:VCALENDAR