Search results
Results From The WOW.Com Content Network
Thermal wind is a meteorological term not referring to an actual wind, but a difference in the geostrophic wind between two pressure levels p 1 and p 0, with p 1 < p 0; in essence, wind shear. It is only present in an atmosphere with horizontal changes in temperature (or in an ocean with horizontal gradients of density ), i.e., baroclinicity .
Roughness length is a parameter of some vertical wind profile equations that model the horizontal mean wind speed near the ground. In the log wind profile, it is equivalent to the height at which the wind speed theoretically becomes zero in the absence of wind-slowing obstacles and under neutral conditions. In reality, the wind at this height ...
Several flow patterns are characteristic of large deformation: confluence, diffluence, and shear flow. Confluence, also known as stretching, is the elongating of a fluid body along the flow (streamline convergence). Diffluence, also known as shearing, is the elongating of a fluid body normal to the flow (streamline divergence). [1]
The wind profile of the atmospheric boundary layer (surface to around 2000 metres) is generally logarithmic in nature and is best approximated using the log wind profile equation that accounts for surface roughness and atmospheric stability. The relationships between surface power and wind are often used as an alternative to logarithmic wind ...
In common usage, wind gradient, more specifically wind speed gradient [1] or wind velocity gradient, [2] or alternatively shear wind, [3] is the vertical component of the gradient of the mean horizontal wind speed in the lower atmosphere. [4] It is the rate of increase of wind strength with unit increase in height above ground level.
When estimating wind loads on structures the terrains may be described as suburban or dense urban, for which the ranges are typically 0.1-0.5 m and 1-5 m respectively. [ 2 ] In order to estimate the mean wind speed at one height ( z 2 {\displaystyle {{z}_{2}}} ) based on that at another ( z 1 {\displaystyle {{z}_{1}}} ), the formula would be ...
The wind blowing parallel to a water surface deforms that surface as a result of shear action caused by the fast wind blowing over the stagnant water. The wind blowing over the surface applies a shear force on the surface. The wind stress is the component of this force that acts parallel to the surface per unit area.
In meteorology the Ellrod index is a technique for forecasting clear-air turbulence (CAT). It is calculated based on the product of horizontal deformation and vertical wind shear derived from numerical model forecast winds aloft.