Atmospheric Stability in WAsP

[Pedro Quiroga]

Hi support team,

I’m working with a cross validation in WAsP, and I want to evaluate if we can improve the wind speed prediction if we make a cross prediction by atmospheric stability regime. The idea is to filter the time series of observed data by stability regime and create an OWC for neutral, stable and unstable condition, and each OWC will be used to predict a neutral, stable and unstable wind speed distribution. My question is if make sense to make a weighted sum of each of the predicted histogram in order to have a global prediction of each site? a similar idea of emergent distribution, which is a weighted sum of wind speed distribution per directional sector.

[Niels Gylling Mortensen]

Dear Pedro,
I have not heard of similar studies and have not done any such studies myself. With the climatological nature of WAsP, we usually recommend to try tweak the average heat fluxes over land and water (WAsP 12 > GWC window > Profile model tab). This can work quite well, see e.g. https://orbit.dtu.dk/en/publications/wind-atlas-for-south-africa-wasa-observational-wind-atlas-for-10--4.

Best regards,

Niels


PS. Adjusting for stability is after you have done all other adjustments, checked the maps, checked for obstacles, etc.

[Pedro Quiroga]

Thanks for your reply. One more question, when I insert a met station, Does WAsP consider it as an obstacle?

[Niels Gylling Mortensen]

Dear Pedro,
No, only if you specify an obstacle member of the hierarchy. The mast itself will provide some flow distortion and 'shelter', but that is not treated at all by the obstacle model. However, you can insert User corrections in the hierarchy, if you have information about such effects.