Roughness in CLM5

[stevenDH]

Hi all

I have performed some fully coupled simulations with CESM and would like to investigate the roughness variable, however it seems I didn't output these variables (they do not appear part of the default output of the model), is there any way I can compute this (or a close proxy) using the other default outputs of the land model such as TLAI or HTOP or something?

Thanks in advance!
Cheers
Steven

 

[oleson]

There are several roughness lengths, for ground and vegetation, for different land surfaces, and for momentum, heat, and moisture. I guess the best thing would be to search for "roughness" in the CLM5 technical note (assuming you are using CLM5):

2. CLM Technical Note — ctsm release-clm5.0 documentation

For example, "The vegetation displacement height

and the roughness lengths are a function of plant height and adjusted for canopy density following Zeng and Wang (2007)". See equations (2.5.125 - 2.5.127).