[GTP] GTP Seminar July 24, 2013

[Carolyn Mueller]

Hello everyone.

Just a reminder of tomorrow's seminar.


GTP Seminar
MULTISCALE ASYMPTOTIC FORMALISMS FOR LANGMUIR CIRCULATION DYNAMICS ON 
OCEAN SUBMESOSCALES
Greg Chini
Mechanical Engineering • University of New Hampshire
This session will be webcast and recorded 
http://www.fin.ucar.edu/it/mms/ml-live.htm

Wednesday, July 24, 2013
Mesa Laboratory, Main Seminar Room
Lecture at 11:00 am

The ocean surface boundary layer (BL) is the site of vigorous, 
multiscale mixing events driven by an array of instability processes. On 
cross-wind scales commensurate with the mixed-layer depth, wind and 
surface-wave-driven Langmuir circulation (LC), characterized by an array 
of counter-rotating vortical structures elongated in the wind direction, 
has long been thought to dominate vertical transport and mixing. More 
recently, a spate of observational, numerical, and theoretical studies 
has demonstrated the profound impact of submesoscale flows, having 
lateral scales ranging from 1-10 km, on upper ocean mixing and 
restratification.

An important question is whether and how these two flow regimes 
interact. Here, multiscale asymptotic formalisms are derived to 
facilitate investigation of LC dynamics over time and horizontal length 
scales commensurate with those of internal waves, symmetric and 
mixed-layer baroclinic instabilities, and other submesoscale BL 
phenomena. Numerical simulations of the resulting asymptotically-reduced 
and multiscale PDEs reveal interesting coarse-scale phenomenology, 
including: a robust 2:1 spatial resonance that may be responsible for 
Y-junction formation in LC windrow patterns; a long-wavelength side-band 
instability of stratified LC; and a 40-fold intensification of 
submesoscale internal-wave vertical velocities induced by nonlinear 
interaction with fine-scale LC. More generally, the multiscale PDEs 
provide a useful framework for rapidly investigating disparate scale 
coupling between large Rossby number, strongly non-hydrostatic LC and 
rotationally influenced, largely hydrostatic submesoscale flows in the 
upper ocean.


Wednesday, July 24, 2013
Mesa Laboratory, Main Seminar Room
Lecture at 11:00 am

-- 
Carolyn Mueller
NCAR IMAGe
1850 Table Mesa Drive
Boulder, CO 80305
http://www2.image.ucar.edu/
Tel: 303 497-2491
Fax: 303-497-2483