Roughness Length

Datasets and Usage C3S - Datasets and Usage
1

Hello. As I know, roughness lenght is crucial to wind at the lowest levels. Over land, surface roughness is dependent upon the surface vegetation. There is a variable named forecast surface roughness in ERA5.  I'm confused about how to calculate this variable. Is this variable also related to high or low vegetation type and high or low vegetation cover? Thanks for any feedback.

587×433 56.7 KB

2

Hi, in my experience aerodynamic roughness lengths are estimated using empirical expressions.

This a topic discussed often for wind energy applications, see references related to softwares WAsP, WRF or others.

BR Rémi