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In Canada, reference wind pressures are used in design and are based on the "mean hourly" wind speed having a probability of being exceeded per year of 1 in 50. The reference wind pressure q is calculated using the equation q = ρv 2 / 2, where ρ is the air density and v is the wind speed. [19]
A wind atlas contains data on the wind speed and wind direction in a region. [1] These data include maps , but also time series or frequency distributions . A climatological wind atlas covers hourly averages at a standard height (10 meters) over even longer periods (30 years) but depending on the application there are variations in averaging ...
Average wind speed is measured using a two-minute average in the United States, [19] and a 10-minute average elsewhere. [20] Wind direction is measured using degrees, with north representing 0 or 360 degrees, with values increasing from 0 clockwise from north. Wind gusts are reported when there is variation of the wind speed of more than 10 ...
Screenshot of the Global Wind Atlas website (version 2.2) The Global Wind Atlas is a web-based application developed to help policymakers and investors identify potential high-wind areas for wind power generation virtually anywhere in the world, and perform preliminary calculations. It provides free access to data on wind power density and wind ...
The log wind profile is generally considered to be a more reliable estimator of mean wind speed than the wind profile power law in the lowest 10–20 m of the planetary boundary layer. Between 20 m and 100 m both methods can produce reasonable predictions of mean wind speed in neutral atmospheric conditions.
Trying to calculate angular moments by naively applying the standard formulas to angular expressions yields absurd results. For example, a dataset that measures wind speeds of 1° and 359° would average to 180°, but expressing the same data as 1° and -1° (equal to 359°) would give an average of 0°.
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 ...
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.