The central point in the wind transformation model of WAsP – the so-called Wind Atlas Methodology – is the concept of a Regional or Generalized Wind Climate, or Wind Atlas. This Generalized Wind Climate is the hypothetical wind climate for an ideal, featureless and completely flat terrain with a uniform surface roughness, assuming the same overall atmospheric conditions as those of the measuring position.
The basic "machine" of WAsP is a flow model, representing the effect of different terrain features:
- terrain height variations
- terrain roughness
- sheltering obstacles
To deduce the Generalized Wind Climate from measured wind in actual terrain the WAsP flow model is used reversely, to remove the local terrain effects. |

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To deduce the wind climate at a location of interest from the Generalized Wind Climate, the WAsP flow model is used to introduce the effect of terrain features.
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The concept of the Regional Wind Climate links the wind data from a measuring mast to the predicted wind climate and wind resources at locations of interest, typically a candidate site for a wind turbine or a wind farm.