WAsP Monin-Obukhov lenght

[dcarvalho]

Hello all,


I have a question about how WAsP deals with the atmospheric stability. I've consulted several articles about WAsP and, it seems that WAsP's submodel that deals with atmospheric stability corrections does not use any Monin-Obukhov lenghts, but only makes the stability corrections considering the heat fluxes.


Is this true? Or, it follows the European Wind Atlas methodology and assumes that the stability correction is a term given by -4.7*(Z/L) and subtracts it to the wind resulting from the logarithmic profile?


I am really struggling with this, any help is appreciated. Thank you

[Niels Gylling Mortensen]

The stability model is described in the European Wind Atlas, if you can get hold of a copy from a (university) library near you. The model is based on M-O similarity theory, but the procedure is simplified so it only requires input of the mean and RMS values of the on- and off-shore heat fluxes.

[dcarvalho]

First of all, thank you very much for your reply. Yes, I am taking a look at the European Wind Atlas, and I saw that the methodology they describe for correcting the logarithmic wind profile due to stability issues is, in short, including the extra term -4.7*(Z/L)(assuming stability) in the logarithmic equation.

So, my question is if WAsP does exactly this, but according to you and some articles I've read, WAsP does what you say. What I am investigating is:

Computing the geostrophic wind through a mesoscale model (WRF, in my case), I will use the logarithmic wind profile (including the term -4.7*(Z/L)) to make the wind atlas using MATLAB routines. The friction velocity will be computed using the Simplified Geostrophic Drag Law. I want to check if applying this correction the results are better than the methodology WAsP follows.

You think this is logic????

Thank you very much