surface roughness length units?

Topics related to current and future physics in the WRF as well as any problems you may have.

surface roughness length units?

Postby twhilton » Tue May 28, 2019 4:07 pm


I am implementing a new land-use type for WRF-NOAHMP (and possibly, at some point, WRF-CLM). I am trying to decipher the units for surface roughness in LANDUSE.TBL (Z0) and VEGPARM.TBL (Z0MIN, Z0MAX).

The only documentation I can find for LANDUSE.TBL are the comments in lines 1906 to 1927 of module_sf_noahdrv.F and this wrfforum post: viewtopic.php?f=22&t=612.

The comments in module_sf_noahdrv.F claim that Z0 in LANDUSE.TBL are in meters. I wonder if that is an error - the Z0 value of 12 for grasslands seems absurdly high if it is meters, and the forest values (50) seem high for the typical forest as well.

I suspect those LANDUSE.TBL Z0 values are in fact centimeters, not meters. Could anyone with more knowledge than I have confirm or deny? Although, if the units are centimeters then the forest value of 50 seems small...

Also, if anyone is aware of any more "official" documentation for LANDUSE.TBL I'd love to hear.



Timothy W. Hilton
Assistant Project Scientist
Environmental Studies Department
University of California, Santa Cruz
Posts: 11
Joined: Mon Sep 11, 2017 11:48 am

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