Research

Research diversity and interdisciplinary focus are the development principles that have driven the creation and growth of the Center. Accordingly, the topics under research by our faculty cover a wide spectrum, particularly for our size. This model of faculty composition stands in contrast to more traditional AOS departments -- we cannot boast great strength in any one particular area beyond the high quality of the research an individual faculty member contributes to that area. The strength of this model is that it maximizes our potential interactions with applied mathematics, and graduate students have a wide choice of research topics from which to choose. A sampling of our research follows (in most cases, more information can be found on individual faculty homepages).

Oliver Bühler works on fundamental topics in wave mean-flow/vortex interaction. For example, he and a collaborator have recently uncovered a mechanism by which a wave-vortex interaction can cause a persistent, cumulative change in the mean state in the absence of dissipation or breaking (Buhler and McIntyre 2003). Such an effect brings into question fundamental parameterizations of gravity waves used in atmospheric models. Buhler also works on coastal vortex dynamics, statistical mechanics, and stratospheric transport.

Edwin Gerber investigates the internal variability of the atmosphere and its relation to climate change. He has developed a hierarchy of idealized models to understand the spatial and temporal structure of intraseasonal variability in the mid and high latitudes, in particular the North Atlantic Oscillation and annular mode patterns of variability (e.g. Gerber and Vallis 2005, 2007). His recent research addresses coupling between the stratosphere and troposphere, with focus on the influence of stratospheric sudden warmings on the troposphere (Gerber and Polvani, 2008). He works on the use (and verification) of numerical models and stochastic techniques to understand fundamental atmospheric processes and climate change predictions.

David Holland's research focuses on polar oceanography and ice dynamics and has led to improved techniques for coupling sea and ocean models. Holland recently showed that the Weddell Polynya results from interactions between topographically generated eddies and surface ice (Holland 2001). He has recently conducted some of the first simulations in which floating ice shelves are included in an ocean general circulation model. Along with Professor Tabak, he is designing a series of rotating tank experiments to investigate dense overflows from high latitude, shallow seas. 

Richard Kleeman is interested in using a range of tools from applied probability theory to simplify and better understand the complex dynamical systems appropriate for the atmosphere and ocean. In recent years he has constructed stochastic models of the climate system and used information theory to analyze the predictability of the atmosphere from a fundamental viewpoint. He is currently using these theoretical tools to develop understanding of how uncertainty flows through complex dynamical models and is also developing stochastic models of the tropical atmosphere. 

Andrew Majda has achieved high distinction over the past 25 years in many branches of applied mathematics, and especially in the area of turbulence research (for example, Majda and Kramer 1999). In recent years he has applied his insights to the study of the climate system. He and his collaborators have made important contributions to tropical meteorology (Majda and Biello 2004), stochastic parameterizations for climate research (Majda, Timofeyev and Vanden-Eijnden 2003) and applications of statistical mechanics to large-scale geophysical flows (Turkington et al. 2001).

Olivier Pauluis is an expert on climate sciences, and particularly on the interactions between moist convection and the atmospheric circulations. His research interests include the feedbacks between large-scale circulation and precipitation (Pauluis 2004), the role of water vapor and moist processes on the maintenance of the atmospheric circulation (Pauluis and Held 2002, Pauluis 2006), the development of high-resolution numerical models to simulate convective systems in the tropics (Pauluis and Garner 2006), and theoretical multi-scale models for the atmosphere (Frierson et al. 2004, Pauluis et al. 2007).

Shafer Smith conducts research focused on the scale and structure of baroclinic instability in Earth's ocean and atmosphere, mesoscale and submesoscale geophysical turbulence, connecting theory to observations of oceanic transport, and stirring and mixing in a range of geophysical flows. In recent papers, Smith and collaborators have demonstrated a new mechanism to explain the mesoscale atmospheric energy spectrum (Tulloch and Smith, 2009), shown that submesoscale observations of temperature and salinity are consistent with stirring by baroclinic mid-ocean eddies (Smith and Ferrari, 2009), and demonstrated that eddy mixing in the Southern Ocean is peaked near a critical layer, about one kilometer below the surface (Smith and Marshall, 2009).

Esteban Tabak has developed during the last few years reduced models that shed light on various aspects of the global circulation. He has made significant contributions to the field of dispersive wave turbulence (Lvov, Polzin and Tabak 2004), which may ultimately explain the origin of the Munk-Garret spectrum of internal waves in the ocean. He is currently working on new models for well--mixed layers in the atmosphere and ocean, on sea--ice dynamics, and on improving our understanding of various processes involved in shelve-slope exchange that are poorly parameterized in present day GCMs.