Wind stresses

When a region includes a large body of water, the roughness cannot be characterized by simply associating with the wave height. Unlike the land, the effective roughness of the water surface is a dynamic variable whose magnitude is influenced by factors such as the wave state and wind stress. There is a variety of models of the air-sea interaction and... 

Hsu, S. A. (1974). A dynamic roughness equation and its application to wind stress determination at air-sea interface. J. Phys. Oceanogr. 4, 116-120. 

Wipperman, F. (1972). A note on parameterization of large scale wind stress at the sea-surface. Beitr. Phys. Atmos. 45, 260-266. 

Some of the NPP models are based on the color imagery and some are not. In the latter, phytoplankton growth is estimated from coupled global circulation and biogeo-chemical models in which water motion controls nutrient availability. The water motion is controlled by climatic factors, such as temperature gradients and wind stress. The latest effort to compare model outputs was conducted with 31 different models and foimd that global estimates for a test year (1998) differed by as much as a factor of 2 The mean results from this model intercalibration experiment are shown in Table 23.7. 

Geostrophic current The advection of water resulting from the balance between gravity, wind stress, and the Coriolis Effect. 

In the experiments used to draw Fig. 20.2, wind speeds were measured at different heights above the water surface. Since wind speed generally decreases when approaching the water surface, these experiments can be compared only if we find a means to transform the wind speeds to a standard height (usually 10 m). Mackay and Yeun (1983) use the standard boundary layer theory with a roughness height of 0.03 cm and a wind stress coefficient of 1.5 x 10 3 to get ... 

The paper explains how safe and economic structures can be realized, and points out the sensitivity and importance of cooling tower design in relation to the wind stresses. 5 refs, cited. 

Dynamic Wind Stresses in Hyperbolic Cooling Towers Abu-Sitta, Salman H. Hashish, Mahmoud G. 

The paper outlines a general procedure for estimating the wind dynamic stresses in hyperbolic cooling towers on the basis of a statistical dynamic approach. Using wind tunnel measurements of pressure fluctuations and assuming that resonance is negligible, predicted wind stresses agreed with measured stresses on an aeroelastic model. The procedure is applied to 451-ft tower. 9 refs, cited. 

Wind stresses are disregarded because of the high ratio of tank... 

Atmospheric transport of elements to the oceans We will conclude our considerations of transport agents and fluxes of materials to the ocean with a brief look at airborne transport of solids. Wind stress on the land surface results in... 

The main source for the generation of the BSGC and its seasonal and interannual variabilities is related to the relative vorticity of the tangential wind stress the influence of the momentum, moisture, and heat fluxes across the sea surface and via the river mouths and straits is significantly lower. 

The main distinctive property of the Black Sea is its inland location and high isolation from the World Ocean. Because of this, formation of the sea hydrological regime and water structure is governed by the outer factors the fluxes of heat, moisture and wind stress via the sea surface, as well as the river runoff. In this connection, the sea is characterized by a high level of its environmental variability. At the same time in different parts of the Black Sea, the influence of the outer factors is very unequal. Therefore, these factors exert a different impact on the formation of hydrological fields and vertical thermohaline structure in the sea. All this confirms the necessity for... 

Nobre, P., and J. Shukla. 1996. "Variations of sea surface temperature, wind stress, and rainfall over the tropical Atlantic and South America." Journal of Climate 9 2464-2479. 

The earlier works by Mague et al. (1974 1977), Venrick (1974), and Kimor (1978) attempted to define some of the environmental factors and conditions that control the N2 fixation activity and distribution of DDA populations. Some have argued that distribution and activity is largely controUed by latitude, temperature, nutrients (i.e., iron, phosphorous), and wind stress for the other co-occurring cyanobacteria. 

Figur 33 1 Physical and biological upwelling response simulated by the Wroblewski (1977) 2-dimensional coastal upwelling model (A) The circulation in the transverse plane normal to the coast, the bottom topography, and the wind stress. The maximum u and w velocities in the field are —2.9 cm s and 1.4 x 10 cm s , respectively. (B) The daily gross primary production of the water column. (C) The distribution of phytoplankton. Contour intervals are 1 jimol N 1. Redrawn with permission from Wroblewski (1977).

Wu J. (1988) Variations of whitecap coverage with wind stress and water temperature. J. Phys. Oceanogr. 18, 1448-1453. 

Warming of the surface ocean by solar heating and turbulence induced by wind stress compete to create a surface mixed layer over most of the ocean that is 10-100 m deep except in some high-latitude areas, where the ocean is mixed more deeply. In the subtropical and... 

To discuss some general features equation (6.5) is further simplified by assuming steady, uniform flow, and by integrating over the depth, H. Wind stress is also neglected, although in some instances this can play a role in the momentum balance near the water surface [317]... 

The upper ocean wind-driven current was described realistically for the first time by Walfried Ekman s landmark theory of 1905. The velocity distribution in the near surface layer of the ocean cannot be determined without additional information about the variation of the Reynolds stress vector with depth. Ekman (1905) assumed the Reynolds stress vector to be equal to the vertical shear of the mean current vector times a constant vertical eddy viscosity. The resulting current profile below the sea surface is the well known Ekman spiral with current speed decreasing exponentially with depth and current direction turning clockwise linear with depth from 45° right-handed to the wind stress vector at the sea surface. 

An alternative perspective is the assumption that the Reynolds stress is an external function of time and depth described as a volume force independent of the mean current (Pollard, 1970). Such a conceptual model is valid if the turbulence generating the Reynolds stress in the surface mixed layer is caused by physical mechanisms that are independent of the mean current. Pollard (1977) suggested that Langmuir circulation might by a very effective mechanism to distribute Reynolds stress downward in the surface mixed layer from the sea surface where all the momentum is received from the wind stress. 

Although the details of the vertical structure of the wind-driven current in the surface mixed layer depend on the vertical distribution of the Reynolds stress in the surface layer, the vertical integrated wind-driven current, the Ekman transport, depends only on the wind stress at the sea surface. 

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