BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Time-Lapse Volumetric Seismic Imaging of Water Masses at a Major O
 ceanic Confluence in the South Atlantic Ocean - Xiaoqing Chen (University 
 of Cambridge)
DTSTART:20230511T103000Z
DTEND:20230511T113000Z
UID:TALK199633@talks.cam.ac.uk
CONTACT:Catherine Pearson
DESCRIPTION:Water-mass interaction processes within the Southern Ocean str
 ongly influence the global oceanic circulation system.  For example\, the 
 western side of the South Atlantic Ocean is dominated by the confluence be
 tween the Brazil Current (BC) and Falkland/Malvinas Current (MC). At this 
 confluence\, tropical/subtropical (i.e. warm and salty) waters are transpo
 rted southward by the BC where they interact with subantarctic (i.e. cold 
 and fresh) waters transported northward by the MC. This interaction create
 s a highly dynamic frontal system that is characterized by complex water m
 ass interactions and intense diapycnal mixing. Here\, we exploit time-laps
 e volumetric seismic imaging of the Brazil-Malvinas Confluence (BMC) in or
 der to elucidate the detailed thermohaline structure of this critical regi
 on. Careful signal processing of a ~25 terabyte survey\, acquired during F
 ebruary 2013\, reveals a spectacular northeastward dipping oceanic front t
 hat extends as deep as ~1800 m. Significantly\, a deep transient mesoscale
  eddy is embedded in this front. This eddy appears to grow and decay over 
 ~11 day period and it has a maximum diameter of ~40 km. Time-lapsed imager
 y also reveals mesoscale to sub-mesoscale complexity at all depths. Long w
 avelength temperature fields extracted from our acoustic velocity measurem
 ents reveal a pattern of cool anomalies on the MC side together with a ste
 ep and fanning temperature gradient close to the front but above the eddy\
 , indicative of heat transfer. Evolution of this prominent eddy embedded i
 n the front can be independently investigated using velocity fields calcul
 ated from the GLORYS12v1 product for the period of interest. Tracked parti
 cles\, which are released daily through the confluence area down to 1800 m
 \, flow along the MC from 40° S  to 36° S and are deflected clockwise by
  the BMC. This flow suggests that the observed eddy is cyclonic and relate
 d to MC recirculation\, as a result of the combination of the steep contin
 ental slope and geometry of the BMC. In this way\, cooler water masses are
  juxtaposed against the front. 
LOCATION:Open Plan Area\, Institute for Energy and Environmental Flows\, M
 adingley Rise CB3 0EZ
END:VEVENT
END:VCALENDAR