The File Creation Process

Creating a complete set of files for input to CLM

1. Create grid and fraction datasets

   First use mkgriddata to create grid and fraction datasets. See the Section called Using mkgriddata to create grid datasets for more information on this.

2. Create domain dataset (if NOT already done)

   Next use mkdatadomain to create a domain file for use by DATM from the grid and fraction datasets just created. This is required, unless a domain file already created was input into mkgriddata on the previous step. See the Section called Using mkdatadomain to create domain datasets for DATM or docn from CLM grid datasets for more information on this.

3. Create surface datasets

   Next use mksurfdata to create a surface dataset, using the grid dataset as input. See the Section called Using mksurfdata to create surface datasets from grid datasets for more information on this.

4. Interpolate aerosol deposition datasets (optional)

   By default the atmosphere model will interpolate these datasets on the fly, so you don't normally need to do this step. A reason you might want to do this is to make the read and interpolation faster, by reducing the amount of data read in and removing the need for the interpolation. So, if you do, you can use aerdepregrid.ncl to regrid aerosol deposition datasets to your new resolution using the grid dataset as input. See the Section called Using aerdepregrid.ncl to interpolate Aerosol deposition datasets for more information on this.

5. Interpolate Nitrogen deposition datasets (optional, but only needed if running CLMCN)

   By default Nitrogen deposition is read in from stream files at 2-degree resolution and interpolated to the resolution you are running at, so you don't need to do this step. As with aerosol deposition datasets a reason you might want to do this is to make the read and interpolation faster, by reducing the amount of data read in and removing the need for the interpolation. So, if you do you can use ndepregrid.ncl to regrid Nitrogen deposition datasets to your new resolution using the grid dataset as input. See the Section called Using ndepregrid.ncl to interpolate Nitrogen deposition datasets for more information on this.

6. Create some sort of initial condition dataset

   You then need to do one of the following three options to have an initial dataset to start from.

   1. Use spinup-procedures to create initial condition datasets

      The first option is to do the spinup procedures from arbitrary initial conditions to get good initial datasets. This is the most robust method to use. See the Section called Spinning up the Satellite Phenology Model (CLMSP spinup) in Chapter 4, the Section called Spinning up the biogeochemistry Carbon-Nitrogen Model (CN spinup) in Chapter 4, or the Section called Spinning up the Carbon-Nitrogen Dynamic Global Vegetation Model (CNDV spinup) in Chapter 4 for more information on this.

   2. Use interpinic to interpolate existing initial condition datasets

      The next option is to interpolate from spunup datasets at a different resolution, using interpinic. See the Section called Using interpinic to interpolate initial conditions to different resolutions for more information on this.

   3. Start up from arbitrary initial conditions

      The last alternative is to run from arbitrary initial conditions without using any spun-up datasets. This is inappropriate when using CLMCN (bgc=cn or cndv) as it takes a long time to spinup Carbon pools.

      Warning

      This is NOT recommended as many fields in CLM take a long time to equilibrate.

7. Enter the new datasets into the build-namelist XML database

   The last optional thing to do is to enter the new datasets into the build-namelist XML database. See Chapter 3 for more information on doing this. This is optional because the user may enter these files into their namelists manually. The advantage of entering them into the database is so that they automatically come up when you create new cases.