The maintenance of the ocean general circulation requires energy input from the wind. Previous studies estimate that the mean rate of wind work (or wind power) acting on the surface currents over the global ocean amounts to 1.1 TW (1 TW ! 10 Watts), though values remain highly uncertain. By analyzing the output from a range of ocean-only models and data assimilations, we show that the tropical ...

At temperate latitudes the synoptic patterns of bird migration are strongly structured by the presence of cyclones and anticyclones, both in the horizontal and altitudinal dimensions. In certain synoptic conditions, birds may efficiently cross regions with opposing surface wind by choosing a higher flight altitude with more favourable wind. We observed migratory passerines at mid-latitudes that...

This work describes a method for estimating vertical fluxes of horizontal momentum carried by short horizontal scale gravity waves (Xx = 10-100 km) using aircraft measured winds in the lower stratosphere. We utilize the in situ wind vector and pressure altitude measurements provided by the Meteorological Measurement System (MMS) on board the ER-2 aircraft to compute the momentum flux vectors at...

Ducted gravity waves are associated with potentially large perturbations in horizontal winds. It may be shown, neglecting friction, that these perturbations are maximized at the surface and minimized at the top of the wave duct, producing perturbation vertical wind shear as well. The magnitude of this shear is maximized in the wave ridge and the wave trough. The perturbation shear may be signif...

Numerical simulations of a bora event, recently occurred in the Adriatic area, are presented. Two reference runs at different horizontal resolution (about 20 km and 8 km) describe the case. Initial conditions for the atmospheric model integration are obtained from ECMWF analyses. Satellite data are used for comparisons. A further run at horizontal resolution of 8 km, using initial satellite sea...

An ocean model response to Hurricane Ivan (2004) over the northwest Caribbean Sea and Gulf of Mexico is evaluated to guide strategies for improving performance during strong forcing events in a region with energetic ocean features with the ultimate goal of improving coupled tropical cyclone forecasts. Based on prior experience, a control experiment is performed using quasi-optimal choices of in...

Laminar free convection heat transfer from vertical and inclined arrays of horizontal isothermal cylinders in air was investigated experimentally and numerically. Experiments were carried out using Mach-Zehnder interferometer and the FLUENT code was used for numerical study. Investigation was performed for vertical and horizontal cylinder spacing from 2 to 5 and 0 to 2 cylinder diameters respec...

in this study, stability of geosynthetic reinforced soil retaining walls investigated using plaxis code that is based on finite element method. the effects of axial stiffness, length and vertical space between geosynthetic layers, internal friction angle of soil wall and cohesion of foundation on deformations of wall and maximum axial force of geosynthetic have been investigated. results of ana...