Hi Rogier, thanks for your answer. In fact, I have two time series, each one corresponding to a different measurement height (60 m and 100 m) in the same met mast, that is to say, I have two anemometers. So, in order to get a comparison between the GWC associated to each one of those anemometers, I used WAsP to calculate the AEP for the same wind farm twice, with the GWC generated. The analysis showed that there are remarkable differences whenever I change the GWC, even if they correspond to the same met mast, but at different heights. My question is: is that difference due to any vertical extrapolation model limitation? If it's not clear yet, please let me know. Thank you once again!