Weakly rotating turbulent Rayleigh-Bénard convection was studied experimentally and numerically. With increasing rotation and large enough Rayleigh number a supercritical bifurcation from a turbulent state with nearly rotation-independent heat transport to another with enhanced heat transfer is observed at a critical inverse Rossby number 1/Roc approximately 0.4. The strength of the large-scale...

We derive upper bounds for the Nusselt number in innnite Prandtl-number rotating convection. The bounds decay algebraically with Taylor number to the conductive heat transport value; the decay rate depends on boundary conditions. We show moreover that when the rotation is fast enough the purely conductive solution is the globally and nonlinearly attractive xed point; the critical rotation rate ...

Rapidly rotating Rayleigh-Bénard convection is studied by combining results from direct numerical simulations (DNS), laboratory experiments, and asymptotic modeling. The asymptotic theory is shown to provide a good description of the bulk dynamics at low, but finite Rossby number. However, large deviations from the asymptotically predicted heat transfer scaling are found, with laboratory experi...

Vertical displacement of the thermocline may be due either to a convergence or a divergence of Ekman transport in the surface layer. Data from ships of opportunity between New Caledonia an¿ Japan are used to compute the wind stress curl, from 1973 to 1980, neglecting the zonal gradients. The pattern is compared to the changes of the 25OC isotherm depth between 5ON\ and 20°S from all data availa...

Abstract. The seminal Ekman (1905) f-plane theory of wind-driven transport at the ocean surface is extended to ? plane by substituting pseudo-angular momentum for zonal velocity in Lagrangian equation. When term added, equations become nonlinear, which greatly complicates analysis. Though rotation relates and meridional directions, transformation simplifies longitudinal dynamics, yields a clear...

In a stratified rotating fluid, frictionally driven circulations couple with the buoyancy field over sloping topography. Analytical and numerical methods are used to quantify the impact of this coupling on the vertical circulation, spindown of geostrophic flows, and the formation of a shelfbreak jet. Over a stratified. slope, linear spindown of a geostrophic along-isobath flow induces cross-iso...

Subantarctic Mode Water (SAMW) is formed by deep convection in winter on the equatorward side of the Antarctic Circumpolar Current. Observations south of Australia show that the SAMW temperature (T) and salinity (S) vary significantly from year to year. The magnitude and density-compensating nature of the temperature and salinity changes cannot be explained by variations in air–sea exchange of ...

The meridional Ekman transport in a zonally reentrant channel may be balanced by diabatic circulations, standing eddies associated with topography, or by Lagrangian mean eddy mass fluxes. A simple model is used to explore the interaction between these mechanisms. A key assumption of this study is that diabatic forcing in the poleward edge of the channel acts to create lighter fluid, as is the c...

[1] Observations, from the Oregon continental shelf, describe the slumping of a coastal upwelling front in response to a reversal of winds from upwellingto downwellingfavorable. Initially, the front outcropped in a surface mixed layer of depth 10–20 m with a pronounced cross-shelf density gradient. Following wind reversal, both the unbalanced cross-shelf pressure gradient and wind-driven Ekman ...