Baroclinic Instability in the Ocean

In a new JPO paper, Ross Tulloch, John Marshall, Chris Hill and Shafer Smith report on an observational, modeling and theoretical study of the scales, growth rates and spectral fluxes of baroclinic instability in the ocean, permitting a discussion of the relation between the instability scale, the first baroclinic deformation scale (R1) and the equilibrated eddy scale.

Malte Jansen is a third year graduate student in PAOC at MIT. He has been using MITgcm in an idealized study to explore how mixing by eddies may influence the equilibrium state of the extra-tropical atmosphere and the Southern Ocean and in particular why the two regimes exhibit such a different equilibrium state.

Motivated by observations indicating rapidly falling annual sea-ice minima, Manfredi Manizza and co-workers have been using an Arctic configuration of MITgcm to explore the Arctic Ocean Carbon Cycle.

Familiar as we are with satellite images of hurricanes, the impact of these powerful storms on the upper ocean is markedly less visible. Dr Sarah Zedler (Texas A&M University) has been using MITgcm to help understand the features that appear in oceanic field data as a result of hurricane passage above.

Prompted by the recent spill in the Gulf of Mexico, Ross Tulloch, Chris Hill and Oliver Jahn have been using MITgcm to compute the vulnerability of individual locations to remote buoyant surface plumes.

This month we look at work by Nicolas Grisouard and Chantal Staquet of the Laboratoire des Ecoulements Geophysiques et Industriels, Grenoble, France, who have been using MITgcm to model internal solitary waves (ISWs) of a kind observed in the Bay of Biscay.

In a first for models simulating the 3d dynamics of both ocean and atmosphere, the MITgcm climate model has been found to exhibit three different stable states for exactly the same set of parameters and external forcings, suggesting that climates may exhibit multiple equilibria even in the presence of a vigorous internal variability sustained by weather systems and ocean-atmosphere-sea ice interactions…

This month we look at work by Tom Haine, Professor of Physical Oceanography at Johns Hopkins University who is using MITgcm to model high-frequency fluctuations in the flow through the Denmark Strait…

This month we look at work by Martha Buckley, David Ferreira, Jean-Michel Campin, Ross Tulloch and John Marshall, who have been using MITgcm to explore what role ocean circulation may play in Atlantic decadal variability. Asking the question: What is the role of the ocean circulation in Atlantic decadal SST variability, Buckley and co-workers use MITgcm to analyse the behavior of thermal anomalies within the framework of an idealised GCM.

This month we focus on work by Gael Forget and the ECCO team who have been using MITgcm to construct a new ocean atlas. By using MITgcm as a means of optimally synthesising data within the framework of a physically accurate general circulation model, OCCA (short for OCean Comprehensible Atlas) provides a singularly accurate 3-year “snap-shot” of the global ocean state for the period December 2003 to November 2006…