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How to change surface roughness length for lake

This post was from a previous version of the WRF&MPAS-A Support Forum. New replies have been disabled and if you have follow up questions related to this post, then please start a new thread from the forum home page.


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Recently, I’m conducting several WRF experiments with lake models. For one case, I’d like to test the sensitivity of surface wind to surface roughness length(Z0). I designed two cases: one is a common simulation without any change; the other one is to increase the Z0 for lakes.
I’m troubled about how to change the lake momentum roughness length. I’ve read the codes of lake model and find that Z0 is set to be a constant if no snow above. And in the LANDUSE.TBL there are different values of Z0 for different landcover; besides I find there is also a VEGPARAM.TBL and it also has different values of Z0 for different landcover. The two tables both have Z0 for water and they different including the Z0 in the lake model. So my questions are :
1) What is the difference between LANDUSE.TBL and VEGPARAM.TBL;
2) What are the differences of the three Z0;
3) If I need to change Z0 for lake, what should I do ?
Thanks for reading my email and hope you can solve my problems.
I've moved this topic from the MPAS-Atmosphere support forum to the WRF Physics forum, since as far as I can tell, this is a question about WRF.
The two tables provide different parameters related to lands type.
VEGPARM is specified for NOAH and RUC, and the parameters in it might be different to that in LANDUSE.TBL. However, these values are specified by the developers based on their information. Although the physical meanings are the same, the values can be different.
In your case, I suppose youshoudl change Z0 in lake module.