Description of MOS

Post-processing can further improve the forecast quality. This can be reached by statistical or dynamical downscaling or a combination of both.

Downscaling means the model output is refined in order to obtain a better horizontal resolution and thereby get a better representation of local effects. Dynamic downscaling can be done in different ways. The resolution of the model can be increased (b). This is easy to be implemented but needs extensive computer resources and is therefore very costly for operational use. CFD models (e.g. WindSim) (c) can also be used. High resolution wind fields around specific sites are used to refine the model output. A combination of both dynamic methods (d) is possible. Statistical methods (such as Model Output Statistics, MOS) are applied to correct site specific errors of the forecast and are easy to use. The disadvantage is that at least one year of measurements and forecast is necessary to develop the correction algorithm.