scholarly journals Reduction of near-inertial energy through the dependence of wind stress on the ocean-surface velocity

2013 ◽  
Vol 118 (6) ◽  
pp. 2761-2773 ◽  
Author(s):  
Willi Rath ◽  
Richard J. Greatbatch ◽  
Xiaoming Zhai
Keyword(s):  
Wind Stress ◽  
Ocean Surface ◽  
Surface Velocity ◽  
Inertial Energy

Wind Stress Dependence on Ocean Surface Velocity: Implications for Mechanical Energy Input to Ocean Circulation

2006 ◽  
Vol 36 (2) ◽  
pp. 202-211 ◽  
Author(s):  
Thomas H. A. Duhaut ◽  
David N. Straub
Keyword(s):  
Wind Stress ◽  
Ocean Circulation ◽  
Energy Input ◽  
Mechanical Energy ◽  
Quadratic Function ◽  
Ocean Surface ◽  
Power Source ◽  
Surface Velocity ◽  
Stress Dependence ◽  
Scaling Arguments

Abstract It is pointed out that accounting for an ocean surface velocity dependence in the wind stress τ can lead to a significant reduction in the rate at which winds input mechanical energy to the geostrophic circulation. Specifically, the wind stress is taken to be a quadratic function of Ua − uo, where Ua and uo are the 10-m wind and ocean surface velocity, respectively. Because |Ua| is typically large relative to |uo|, accounting for a uo dependence leads only to relatively small changes in τ. The change to the basin-averaged wind power source, however, is considerably larger. Scaling arguments and quasigeostrophic simulations in a basin setting are presented. They suggest that the power source (or rate of energy input) is reduced by roughly 20%–35%.

scholarly journals Reducing Climatology Bias in an Ocean–Atmosphere CGCM with Improved Coupling Physics

2005 ◽  
Vol 18 (13) ◽  
pp. 2344-2360 ◽  
Author(s):  
Jing-Jia Luo ◽  
Sebastien Masson ◽  
Erich Roeckner ◽  
Gurvan Madec ◽  
Toshio Yamagata
Keyword(s):  
Wind Stress ◽  
Surface Current ◽  
Ocean Surface ◽  
Tropical Pacific ◽  
Equatorial Pacific ◽  
Eastern Pacific ◽  
Cold Tongue ◽  
Easterly Wind ◽  
Ocean Atmosphere ◽  
The Tropical Pacific

Abstract The cold tongue in the tropical Pacific extends too far west in most current ocean–atmosphere coupled GCMs (CGCMs). This bias also exists in the relatively high-resolution SINTEX-F CGCM despite its remarkable performance of simulating ENSO variations. In terms of the importance of air–sea interactions to the climatology formation in the tropical Pacific, several sensitivity experiments with improved coupling physics have been performed in order to reduce the cold-tongue bias in CGCMs. By allowing for momentum transfer of the ocean surface current to the atmosphere [full coupled simulation (FCPL)] or merely reducing the wind stress by taking the surface current into account in the bulk formula [semicoupled simulation (semi-CPL)], the warm-pool/cold-tongue structure in the equatorial Pacific is simulated better than that of the control simulation (CTL) in which the movement of the ocean surface is ignored for wind stress calculation. The reduced surface zonal current and vertical entrainment owing to the reduced easterly wind stress tend to produce a warmer sea surface temperature (SST) in the western equatorial Pacific. Consequently, the dry bias there is much reduced. The warming tendency of the SST in the eastern Pacific, however, is largely suppressed by isopycnal diffusion and meridional advection of colder SST from south of the equator due to enhanced coastal upwelling near Peru. The ENSO signal in the western Pacific and its global teleconnection in the North Pacific are simulated more realistically. The approach as adopted in the FCPL run is able to generate a correct zonal SST slope and efficiently reduce the cold-tongue bias in the equatorial Pacific. The surface easterly wind itself in the FCPL run is weakened, reducing the easterly wind stress further. This is related with a weakened zonal Walker cell in the atmospheric boundary layer over the eastern Pacific and a new global angular momentum balance of the atmosphere associated with reduced westerly wind stress over the southern oceans.

Ocean surface wind, wind stress, and drag coefficient remote sensing by SAR

2005 ◽  
Author(s):  
Jingsong Yang ◽  
Weigen Huang ◽  
Qingmei Xiao ◽  
Changbao Zhou ◽  
Paris W. Vachon
Keyword(s):  
Remote Sensing ◽  
Drag Coefficient ◽  
Wind Stress ◽  
Surface Wind ◽  
Ocean Surface ◽  
Ocean Surface Wind

A Thickness-Weighted Average Perspective of Force Balance in an Idealized Circumpolar Current

2017 ◽  
Vol 47 (2) ◽  
pp. 285-302 ◽  
Author(s):  
Todd Ringler ◽  
Juan A. Saenz ◽  
Phillip J. Wolfram ◽  
Luke Van Roekel
Keyword(s):  
Surface Layer ◽  
Wind Stress ◽  
Potential Vorticity ◽  
Weighted Average ◽  
Ocean Surface ◽  
Force Balance ◽  
Mean Flow ◽  
Meridional Transport ◽  
Circumpolar Current ◽  
Meridional Advection

AbstractThe exact, three-dimensional, thickness-weighted averaged (TWA) Boussinesq equations are used to diagnose eddy–mean flow interaction in an idealized circumpolar current (ICC). The force exerted by mesoscale eddies on the TWA velocity is expressed as the divergence of the Eliassen–Palm flux tensor. Consistent with previous findings, the analysis indicates that the dynamically relevant definition of the ocean surface layer is composed of the set of buoyancy coordinates that ever reside at the ocean surface at a given horizontal position. The surface layer is found to be a physically distinct object with a diabatic and force balance that is largely isolated from the underlying adiabatic region in the interior. Within the ICC surface layer, the TWA meridional velocity is southward/northward in the top/bottom half and has a value near zero at the bottom. In the top half of the surface layer, the zonal forces due to wind stress and meridional advection of potential vorticity act to accelerate the TWA zonal velocity; equilibrium is obtained by eddies decelerating the zonal flow via a downward flux of eastward momentum that increases with depth. In the bottom half of the surface layer, the accelerating force of the wind stress is balanced by the eddy force and meridional advection of potential vorticity. The bottom of the surface layer coincides with the location where the zonal eddy force, meridional advection of potential vorticity, and zonal wind stress force are all zero. The net meridional transport Sf within the surface layer is a small residual of its southward and northward TWA meridional flows. The mean meridional gradient of the surface layer buoyancy is advected by Sf to balance the surface buoyancy flux.

scholarly journals An Assessment of the Uncertainties in Ocean Surface Turbulent Fluxes in 11 Reanalysis, Satellite-Derived, and Combined Global Datasets

2011 ◽  
Vol 24 (21) ◽  
pp. 5469-5493 ◽  
Author(s):  
Michael A. Brunke ◽  
Zhuo Wang ◽  
Xubin Zeng ◽  
Michael Bosilovich ◽  
Chung-Lin Shie
Keyword(s):  
Wind Stress ◽  
Coupled System ◽  
Surface Flux ◽  
Ocean Surface ◽  
Turbulent Fluxes ◽  
Department Of Energy ◽  
Strong Wind ◽  
Wind Speeds ◽  
Direct Covariance ◽  
Environmental Prediction

Abstract Ocean surface turbulent fluxes play an important role in the energy and water cycles of the atmosphere–ocean coupled system, and several flux products have become available in recent years. Here, turbulent fluxes from 6 widely used reanalyses, 4 satellite-derived flux products, and 2 combined product are evaluated by comparison with direct covariance latent heat (LH) and sensible heat (SH) fluxes and inertial-dissipation wind stresses measured from 12 cruises over the tropics and mid- and high latitudes. The biases range from −3.0 to 20.2 W m−2 for LH flux, from −1.4 to 6.0 W m−2 for SH flux, and from −7.6 to 7.9 × 10−3 N m−2 for wind stress. These biases are small for moderate wind speeds but diverge for strong wind speeds (>10 m s−1). The total flux biases are then further evaluated by dividing them into uncertainties due to errors in the bulk variables and the residual uncertainty. The bulk-variable-caused uncertainty dominates many products’ SH flux and wind stress biases. The biases in the bulk variables that contribute to this uncertainty can be quite high depending on the cruise and the variable. On the basis of a ranking of each product’s flux, it is found that the Modern-Era Retrospective Analysis for Research and Applications (MERRA) is among the “best performing” for all three fluxes. Also, the European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis (ERA-Interim) and the National Centers for Environmental Prediction–Department of Energy (NCEP–DOE) reanalysis are among the best performing for two of the three fluxes. Of the satellite-derived products, version 2b of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF2b) is among the best performing for two of the three fluxes. Also among the best performing for only one of the fluxes are the 40-yr ERA (ERA-40) and the combined product objectively analyzed air–sea fluxes (OAFlux). Direction for the future development of ocean surface flux datasets is also suggested.

scholarly journals The Response of Closed Channels to Wind Stresses

1965 ◽  
Vol 18 (3) ◽  
pp. 219 ◽  
Author(s):  
LM Fitzgerald ◽  
WW Mansfield
Keyword(s):  
Experimental Data ◽  
Velocity Profile ◽  
Wind Stress ◽  
Smooth Surface ◽  
Surface Velocity ◽  
Surface Slope ◽  
Closed Channel ◽  
Velocity Surface ◽  
Smooth Tubes

The surface velocity, surface slope, and velocity profile produced by the application of a wind stress to the smooth surface of a closed channel have been determined by adapting the empirical laws of flow in smooth tubes. The estimated responses agree well with the available experimental data.

Sign in / Sign up

Export Citation Format

Share Document