BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:The role of convective vortices in accumulating buoyant material i
 n the ocean - Jenny Dingwall\, Cambridge
DTSTART:20211125T113000Z
DTEND:20211125T123000Z
UID:TALK165910@talks.cam.ac.uk
CONTACT:Catherine Pearson
DESCRIPTION:Buoyant material such as microplastics tend to accumulate near
  the ocean surface in regions with convergent surface currents where they 
 can be harmful to marine life. In this talk\, we investigate the small-sca
 le transport and accumulation of buoyant material by small-scale turbulenc
 e in the ocean mixed layer under combined wind and convective forcing usin
 g large-eddy simulations. We model non-inertial buoyant particles with a c
 ombination of buoyant tracers and Lagrangian surface particles\, which all
 ows us to explore a wide range of buoyancies. Surface cooling drives conve
 ction\, and under this regime persistent convective vortices form which tr
 ap buoyant material\, leading to large concentrations. Despite their small
  size\, the convective vortices that form exhibit a bias towards cyclonic 
 vorticity. We find that the average time a particle spends inside a convec
 tive vortex is long enough for vortex stretching to amplify planetary vort
 icity and that subsequently particle vorticity increases exponentially. Fo
 r sufficiently weak winds\, convective vortices survive but become less ef
 fective at clustering material as the wind stress increases. Under strong 
 wind forcing\, convective vortices are no longer visible\, but some partic
 le clustering occurs in downwelling regions associated with longitudinal w
 ind rolls.
LOCATION:Open Plan Area\, BP Institute\, Madingley Rise CB3 0EZ
END:VEVENT
END:VCALENDAR