Oregon State University

College of Earth, Ocean, and Atmospheric Sciences

Physics of Oceans and Atmospheres

Roger M. Samelson

Instability and Predictability

My interests in instability and predictability include both the intrinsic dynamics of disturbance growth in geophysical fluid flows, and the associated factors that control the accuracy of environmental forecasts, in the latter case especially for coastal ocean flows.

instability

A recent result in this area of general dynamical interest (Wolfe and Samelson, 2007) was the discovery by my student C. Wolfe (Ph.D., 2006) of an efficient method for the construction of norm-independent Lyapunov vectors for a high-dimensional system from a small set of singular vectors. The figure above shows some diagnostics relating to this method in a weakly nonlinear model of baroclinic waves. This method has recently been picked up by the physics community (e.g., Szendro et al., Spatiotemporal structure of Lyapunov vectors in chaotic coupled-map lattices, Phys. Rev. E, 76, DOI: 10.1103/PhysRevE.76.025202).

Recent Publications

Shaman, J., R. M. Samelson, and E. Tziperman, 2012. Complex wavenumber Rossby wave ray tracing. J. Atmos. Sci, 69, 2112-2133.

Skyllingstad, E. D., and R. M. Samelson, 2012. Baroclinic frontal instabilities and turbulent mixing in the surface boundary layer, Part 1: Unforced simulations. Journal of Physical Oceanography, 42, 1701-1716.

Kim, S., R. M. Samelson, and C. Snyder, 2009. Ensemble-based estimates of the predictability of wind-driven coastal ocean flow over topography. Monthly Weather Review, 137, 2515-2537, DOI: 10.1175/2009MWR2631.1.

Durski, S. D., R. M. Samelson, J. S. Allen, and G. D. Egbert, 2008. Normal-mode instabilities of a time-dependent coastal upwelling jet. Journal of Physical Oceanography, 38, 2056–2071.

Wolfe, C. L., and R. M. Samelson, 2008. Singular vectors and time-dependent normal modes of a baroclinic wave-mean oscillation. Journal of the Atmospheric Sciences, 65, 875-894.

Wolfe, C. L., and R. M. Samelson, 2007. An efficient method for recovering Lyapunov vectors from singular vectors. Tellus, 59A, 355-366.

publications