The Sodar system, a new version of an old idea, is based on emission of sonic impulses and subsequent recording and analysing of the back-scatter from the atmosphere. From the gathered data, scientists can measure the vertical profile of potential wind energy. With this approach, uncertainties involved in extrapolating vertical data from wind measurements carried out at ground level can be ruled out. The measurement data is fed into the computer simulations, from which the three dimensional wind fields can be deduced. From this it is possible to determine suitable locations for wind turbines. The beauty of the procedure is that wide areas of terrain can be assessed simultaneously during the search for locations so that alternative locations can be evaluated without having to take a lot of measurements, Schaefer says.
A potentially commercial system for remote sensing measurement of wind speeds coupled with a computer simulation model has been developed for the complex wind conditions of hilly and mountainous areas by the Fraunhofer Institute for Atmospheric Environmental Research in Germany. The vertical wind profile at a planned location is measured over a period of several months using acoustic remote sensing, a system which has been dubbed "Sodar," says Klaus Schaefer of the institute.