How does NLCD land use data map to UCM urban types?

[mahdad]

Hello,

I am trying to understand the mapping between NLCD and WRF's urban types. I would appreciate any help.

In URBPARM.TBL, there are three urban categories which will then be used in SLCUM: 1) Low density residential, 2) High density residential,
# and 3) Commercial

On the other hand NLCD has four urban categories: 23) Developed Open Space, 24) Developed Low Intensity, 25) Developed Medium Intensity, 26) Developed High Intensity.
How does NLCD's land use categories mapped to WRF's urban types?

Looking at VEGPARM.TBL and LANDUSE.TBL files in recent versions of WRF (3.9 for me), it seems that VEGPARM.TBL maps Low density residential to number 24 (Developed Low Intensity) and High density residential to 26 (Developed High Intensity).

So I have two questions:

1. What is happening to categories 23 and 25 in WRF? Are they mapped to any of URBPARM.TBL urban types for computations? Where?

• VEGPARM.TBL seems to map commercial to number 99 which does not exist in NLCD categories at all. Does this mean there is no Commercial parameterization for NLCD data in WRF?

Thank you,
Mahdad

 

[kwerner]

Hi Mahdad,
We don't consider V3.9 to be a recent version and don't support anything prior to V4 anymore. If you use the most recent code (V4.3.3), you'll see there are 5 urban categories included:

13 Urban and Built-up
23 Developed Open Space
24 Developed Low Intensity
25 Developed Medium Intensity
26 Developed High Intensity

The only surface scheme that uses the VEGPARM.TBL is the Noah scheme. If that's the one you're using, both the URBPARM.TBL and VEGPARM.TBL will be used, and the URBPARM.TBL contains information for commercial parameterization.

 

[mahdad]

Hi Kelly,

Thank you for getting back to me. It seems WRF 3.9 and 4.3.3 are the same in terms of URBPARM categories. I just checked and in URBPARM.TBL in WRF4.3.3 and it has the following three categories similar to 3.9:
1) Low density residential, 2) High density residential,# and 3) Commercial:

The 5 URBAN categories you mentioned that are in VEGPARM.TBL are the same in both versions. My question is how the 4 categories of Urban areas under NLCD categories (i.e. 23 Developed Open Space 24 Developed Low Intensity 25 Developed Medium Intensity 26 Developed High Intensity) are mapped to those in URBPARM.TBL?

In the paper on the first SLUCM implementation in WRF (https://ral.ucar.edu/sites/default/files/public/product-tool/WRF-LSM-Urban.pdf) it says

The land use categories 21 and 22 should be mapped to land use category 31 (Low density residential), The land use category 23 (High density residential) should be mapped to 32, and
The land use category 24 should be mapped to 33 (Commercial). However, this is not what is done in the current versions. Are there other places in the code where these mapping from categories 23 and 25 in NLCD to URBPARM categories are done?

Thank you,
Mahdad

 

[kwerner]

Mahdad,
I've been trying to inquire about this from a physics specialist in our group. Unfortunately these schemes are contributed to us from the NCAR/RAL lab (the owners of the urban document you refer to) and they know the ins and outs of the code much better. Our specialist said they would guess the mapping is done in WPS, where it used NLCD to fill these categories if this is a N. American domain. Otherwise, they aren't sure where they come from. It may be worthwhile reaching out to someone in the RAL group to get a refined answer.

 

[mahdad]

Hi Kelly,

Thank you very much. I appreciate it. I will reach out to them.

Best,
Mahdad