Multiple Roughness length rose in one project

[Chlee]

I found one very interesting issue regards with multiple roughness length rose in one WAsP project and I described my process as following:

1. I made a offshore wind farm project map with predefined roughness length of 50kmx50km and load to my WAsP Project. The roughness length rose looked like 0 for left side and 0.03~1.2 for right side.
2. I selected a semi-offshore met mast as wind atlas source.
3. I inserted two wind turbine in offshore area which is 8km away from semi-offshore met mast and each wind turbine has 900m space.
4. I perform AEP calculation and revived one value.

However, if I assigned individual roughness length rose to each wind turbine I will get 1% higher AEP than original value.

Is it possible for WAsP to apply multiple roughness length rose in one project? How WAsP to deal roughness length rose conflict?

[Mark Kelly]

Hello (to user Chlee),
The use of z0 roses is obsolete, and maps are used/preferred; however one can inspect the z0-rose to see what WAsP is doing.
How are you assigning "individual" z0 "to each wind turbine"?
--
with kind regards,
Mark Kelly, DTU Wind Energy / WAsP team