Next Talk

Speaker: Shafer Smith
Title: Baroclinic turbulence in Earth's oceans
Date and time: April 28, 1:00 p.m. (pizza and drinks at 12:45 p.m.)
Venue: WWH 1302

Abstract

I'll discuss the nonlinear equilibrated states of a two-parameter family of idealized local mean flows that capture the primary mesoscale baroclinic instability types found in the world's oceans. The model flow yields a mean potential vorticity (PV) gradient that consists of baroclinic part, equal to the stretching term from the baroclinic shear, and a depth-averaged part, equal to the sum of beta and the stretching associated with lateral buoyancy gradients at the ocean's surface. The model may be susceptible to Phillips-type baroclinic instability, arising from sign changes in the baroclinic PV gradient, Charney-type instability, which occurs when the surface buoyancy gradient has the opposite sign of the barotropic PV gradient, or both (and may be stable for a narrow slice of parameter space). The two instability types (which may occur alone or in the same flow) lead to distinct turbulent states and eddy fluxes. In some instances, the equilibrated flow exhibits a transition scale below which energetic submesoscale flows develop, displaying features that bear resemblance to Surface Quasigeostrohphic (SQG) turbulence. When such flows result from a Charney-type instability, however, the submesoscale range is non-inertial, being forced at all scales by submesoscale instabilities (akin to, but weaker than Mixed Layer Instabilities). These flows also exhibit a turbulent 'boundary layer,' with a thickness given roughly by the Charney depth scale from the associated linear instability problem. The detailed structure of the turbulence resulting from this family of mean flows provides a useful simplified model for the regional variation of eddy structure in the global ocean.

About this seminar

This seminar is meant to benefit young mathematicians, particularly graduate students and postdocs.
It aims to accomplish the following: The research talks should be fairly introductory and accessible to students and non-specialists in the audience.

Schedule Spring 2017

March 10

Speaker: Ben Blum-Smith
Title:Invariant polynomials and quotients of spheres
Abstract

March 24

Speaker: Eric Vanden-Eijnden
Title:Small Noise, Big Impact: The Inexorable Effect of Random Perturbations on Dynamical Systems
Abstract

March 31

Speaker: Afonso Bandeira
Title:On Phase Transitions for Spiked Random Matrix and Tensor Models
Abstract

April 14

Speaker: Thomas Leblé
Title:1d/2d log-gases: searching for transitions
Abstract

April 28

Speaker: Shafer Smith
Title:Baroclinic turbulence in Earth's oceans
Abstract

Contact Info

If you would like to give a talk or ask a question about the seminar, please contact one of the seminar organizers:

Alexisz Gaalgaal [at] cims [dot] nyu [dot] edu
Reza Gheissarireza [at] cims [dot] nyu [dot] edu
Benjamin McKennamckenna [at] cims [dot] nyu [dot] edu

Previous semesters

Fall 2016 schedule

Spring 2016 schedule

Fall 2015 schedule

Spring 2015 schedule

Fall 2014 schedule

Spring 2014 schedule

Fall 2013 schedule

Spring 2013 schedule

Fall 2012 schedule

Spring 2013 schedule

Fall 2011 schedule

Spring 2011 schedule

Descriptions of earlier talks are here.

Department of Mathematics
Courant Institute of Mathematical Sciences
New York University
251 Mercer St.
New York, NY 10012