WRF-URBAN

Description

Local Climate Zones (LCZs)

The LCZ classification scheme describes and characterizes the surface structure and surface cover of cities in 17 types of zones for urban studies in weather simulations (more information at: LCZs (Stewart & Oke, 2012). To use the LCZ data there are two options.

Using geogrid directly from WPS v4.5

The release of WRF v4.5 included a new geogrid table, GEOGRID.TBL.ARW_LCZ, that includes an entry for a global 100-m LCZ dataset. The WPS Geographical Input Data Mandatory for Specific Applications is already dowloaded in hydra in the same geog_data_path defined before.

NOTE: If you are not using hydra, you can dowload the data directly from the following link: CGLC-MODIS-LCZ_100m. Once the data is downloaded and placed into the geog folder, untar the file and it is ready for use.

• Go to the geogrid folder created before and copy the GEOGRID.TBL.ARW_LCZ.

$ cd $WORKDIR/WPS/geogrid
$ cp $WRFversion/WPS/geogrid/GEOGRID.TBL.ARW_LCZ ./GEOGRID.TBL

• Run geogrid.exe and you are ready to use the data.

NOTE: The use of LCZ data require the addition and change of some parameters in the WRF namelist, these changes will be descibed in real section.

$ cp /share/WRF/launch_geogrid_intel.pbs ./
$ qsub launch_geogrid_intel.pbs

Using w2w

If you are not using WRF v4.5 or higher, or you want to use data from the World Urban Dataset and Access Portal Tools WUDAPT. There is an additional step you need to follow after running geogrid.exe without linking the GEOGRID.TBL.ARW_LCZ. w2w is a python tool to force the LCZ categorization into the geogrid resulting file. To compile w2w you need two input files, the geogrid resulting file geo_em.d[nn].nc and the LCZ Global Map from WUDAPT.

The LCZ Global Map covers the globe with 100m resolution and it is published in the open-access data through the following link in TIFF format. NOTE: The size of the file may cause some problems when running w2w, so it is recommended to crop the file around your study area before using w2w tool.

• Install the w2w tool:

$ pip install git+https://github.com/matthiasdemuzere/w2w

• Run w2w with the input files detailed above.

NOTE: Both the LCZ file and the geo_em file must be in the same input_directory

$ w2w input_directory LCZ_cropped_file.tif geo_em.d[nn].nc

• w2w creates four files saving the original geo_em.dXX.nc file:
  • geo_em.d[nn].nc: Original geo_em file
  • geo_em.d[nn]_NoUrban.nc: Urban areas are replaced with the dominant surrounding rural land use.
  • geo_em.d[nn]_LCZ_extent.nc: The extension of urban areas is updated using LCZ.
  • geo_em.d[nn]_LCZ_params.nc: Urban areas are described using LCZ categories.

NOTE: To run metgrid.exe using the geo_em.dXX_LCZ_params.nc file, you have to change the file name to the name of the original file, and continue with the following steps.