Q. What can the Ruggedness Index (RIX) do for me when I work with complex terrain?
A. The use of the ruggedness index (RIX) belongs to the advanced use of WAsP. In the WAsP help system you can find a description of RIX as an objective measure of the extent of steep slopes in an area. Also, how the difference in RIX values between the met. station (on which the wind atlas is based) and the wind turbine site(s) can be used to estimate prediction errors. In case of large RIX differences, the articles referred to in the Help system indicate the size of the wind speed prediction error. In principle, you could use this to make production correction to be applied to the final WAsP prediction – however, the accuracy of such a procedure would completely be your own responsibility. The RIX value is first of all a tool by which you can judge whether WAsP is working within or outside its performance envelope, whether prediction errors may be expected, and the sign and approximate magnitude of such errors. See the Literature page for more information.