Wind map

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Global distribution of mean wind speeds at a height of 10 meters

Wind maps show the wind conditions, in particular the wind speed , in an area in a cartographic manner. They are required, for example, for planning buildings, for choosing the location of wind power plants , in the insurance industry or in shipping.

Wind maps have a long tradition in climate atlases. The creation was initially based mainly on estimates of wind speed. As more reliable information is needed today, it is created on the basis of measurement data.

Basics

Wind speed and direction depend on various factors. While the wind blows almost undisturbed and reaches relatively high speeds in flat, level terrain or over water, in topographically moving terrain not only the average speed is lower, but the wind direction is also influenced by the shape of the terrain. In such areas the wind speed on the mountain tops and ridges is on average higher than in the valleys. The influence of topography and land use on the wind decreases with height above ground. Since the influence of the frictional force of the ground decreases with height, the wind speed increases sharply, especially in the first 100 m.

conditions

Because of these influencing factors on the wind, the data shown in wind maps must be adapted to the respective purpose. When planning buildings or for risk assessment in the insurance industry, the maximum wind load to be expected, i.e. H. the wind pressure on a structure several meters above the ground of interest. For the location planning of wind turbines, the mean wind speed at hub height of the wind turbines is required.

Statistical wind field model

The German Weather Service has created a wind map for Germany based on long-term measurement data from around 220 wind measurement stations. According to an international agreement, the wind speed was measured in flat, open terrain at a height of 10 m above ground or converted to this height. The influence of individual obstacles such as trees was also eliminated.

In the statistical wind field model of the German Weather Service, the wind speed is shown as a function of various parameters that were determined by a regression analysis from the adjusted measurement data. With the help of the determined parameters, the mean wind speed for the whole of Germany was shown in a grid of 200 × 200 m².

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