### roughness lenght at the lowest cells

Posted:

**Tue Mar 10, 2020 8:41 pm**Hi all,

I read a previous post about the roughness length (z0) at the lowest cells. I know that a high value of z0 is not recommendable, because z0 is automatically reduced to half the size of the lowest grid cell.

So, if my model has 50 × 50 × 30, the grid resolution is 1, 1, 2, and my roughness length is 0.1 I want to know how to calculate the roughness length at the lowest cells. Is roughness length the same for the 5 lowest cells?

Thank you!

Best regards,

I read a previous post about the roughness length (z0) at the lowest cells. I know that a high value of z0 is not recommendable, because z0 is automatically reduced to half the size of the lowest grid cell.

So, if my model has 50 × 50 × 30, the grid resolution is 1, 1, 2, and my roughness length is 0.1 I want to know how to calculate the roughness length at the lowest cells. Is roughness length the same for the 5 lowest cells?

Thank you!

Best regards,