Index Catalog // ScholarsArchive@OSU

Observations and modelling of fronts and frontogenesis in the upper ocean

Creator:: Samelson, Roger M.
Resource Type:: Dissertation

Note on a baroclinic analogue of vorticity defects in shear

Creator:: Samelson, Roger M.
Abstract:: An approach developed recently to study the dynamics of vorticity defects in homogeneous shear flow extends naturally to the case of baroclinic, quasi-geostrophic flow. It is shown that an inviscid geostrophic flow with uniform vertical shear may be destabilized by introducing a `potential vorticity defect', an arbitrarily small but sufficiently...
Resource Type:: Article

Lyapunov, Floquet, and singular vectors for baroclinic waves

Creator:: Samelson, Roger M.
Abstract:: The dynamics of the growth of linear disturbances to a chaotic basic state is analyzed in an asymptotic model of weakly nonlinear, baroclinic wave-mean interaction. In this model, an ordinary differential equation for the wave amplitude is coupled to a partial differential equation for the zonal flow correction. The leading...
Resource Type:: Article

Instability of the Chaotic ENSO: The Growth-Phase Predictability Barrier

Creator:: Samelson, Roger M. and Tziperman, Eli
Abstract:: The local predictability of the El Nin˜o–Southern Oscillation (ENSO) is examined by the analysis of the evolution of small disturbances to an unstable 4.3-yr ENSO cycle in the Cane–Zebiak model forced by perpetual July conditions. The 4.3-yr cycle represents the dominant near-recurrent behavior in this weakly chaotic regime, so analysis...
Resource Type:: Article
Full Text:: -Phase Predictability Barrier ROGER M. SAMELSON College of Oceanic and Atmospheric Sciences, Oregon

Towed thermister chain observations of fronts in the subtropical North Pacific

Creator:: Samelson, Roger M. and Paulson, Clayton A.
Abstract:: A thermistor chain was towed 1400 km through the eastern North Pacific subtropical frontal zone in January 1980. The observations resolve surface layer temperature features with horizontal wavelengths of 0.2-200 km and vertical scales of 10-70 m. The dominant features, which have horizontal wavelengths of 10-100 km, amplitudes of 0.2°-1.0°C,...
Resource Type:: Article
Full Text:: Towed Thermistor Chain Observations of Fronts in the Subtropical North Pacific ROGER M. SAMELSON 1

Singular Vectors and Time-Dependent Normal Modes of a Baroclinic Wave-Mean Oscillation

Creator:: Wolfe, Christopher L. and Samelson, Roger M.
Abstract:: Linear disturbance growth is studied in a quasigeostrophic baroclinic channel model with several thousand degrees of freedom. Disturbances to an unstable, nonlinear wave-mean oscillation are analyzed, allowing the comparison of singular vectors and time-dependent normal modes (Floquet vectors). Singular vectors characterize the transient growth of linear disturbances in a specified...
Resource Type:: Article
Full Text:: Wave-Mean Oscillation CHRISTOPHER L. WOLFE* AND ROGER M. SAMELSON College of Oceanic and Atmospheric

Normal-Mode Analysis of a Baroclinic Wave-Mean Oscillation

Creator:: Wolfe, Christopher L. and Samelson, Roger M.
Abstract:: The stability of a time-periodic baroclinic wave-mean oscillation in a high-dimensional two-layer quasigeostrophic spectral model is examined by computing a full set of time-dependent normal modes (Floquet vectors) for the oscillation. The model has 72 × 62 horizontal resolution and there are 8928 Floquet vectors in the complete set. The...
Resource Type:: Article
Full Text:: CHRISTOPHER L. WOLFE AND ROGER M. SAMELSON College of Oceanic and Atmospheric Sciences, Oregon State

Quasi-Geostrophic Topographically Generated Mean Flow over the Continental Margin

Creator:: Samelson, Roger M. and Allen, J. S.
Abstract:: Observations of oppositely directed, monthly mean alongshore currents and wind stress over the continental margin off the Pacific coast of North America motivate the theoretical examination of mean flow generation by topographic lee-wave drag. We formulate a barotropic model for wind-forced shelf-slope flow over variable topography. Our central objective is...
Resource Type:: Article

Semigeostrophic Wind-Driven Thermocline Upwelling at a Coastal Boundary

Creator:: Samelson, Roger M. and de Szoeke, Roland A.
Abstract:: We formulate analytically and solve numerically a semigeostrophic model for wind-driven thermocline upwelling at a coastal boundary. The model has a variable-density entraining mixed layer and two homogeneous interior layers. All variables are uniform alongshore. The wind stress and surface heating are constant. The system is started from rest, with...
Resource Type:: Article

Summertime Coupling between Sea Surface Temperature and Wind Stress in the California Current System

Creator:: Chelton, Dudley B., Schlax, Michael G., and Samelson, Roger M.
Abstract:: Satellite observations of wind stress and sea surface temperature (SST) are analyzed to investigate ocean–atmosphere interaction in the California Current System (CCS). As in regions of strong SST fronts elsewhere in the World Ocean, SST in the CCS region is positively correlated with surface wind stress when SST fronts are...
Resource Type:: Article
Full Text:: , Corvallis, Oregon ROGER M. SAMELSON College of Oceanic and Atmospheric Sciences, and Cooperative Institute

ScholarsArchive@OSU

Observations and modelling of fronts and frontogenesis in the upper ocean

Note on a baroclinic analogue of vorticity defects in shear

Lyapunov, Floquet, and singular vectors for baroclinic waves

Instability of the Chaotic ENSO: The Growth-Phase Predictability Barrier

Towed thermister chain observations of fronts in the subtropical North Pacific

Singular Vectors and Time-Dependent Normal Modes of a Baroclinic Wave-Mean Oscillation

Normal-Mode Analysis of a Baroclinic Wave-Mean Oscillation

Quasi-Geostrophic Topographically Generated Mean Flow over the Continental Margin

Semigeostrophic Wind-Driven Thermocline Upwelling at a Coastal Boundary

Summertime Coupling between Sea Surface Temperature and Wind Stress in the California Current System

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