NCAR Land Surface Model (NCAR LSM version 1)

Model Availability


The NCAR LSM is available for all interested users. Please read the copyright notice and disclaimer .

The NCAR LSM package consists of 4 compressed tar files:

You can copy these tar files to your home system. If you are using "Netscape", click on the file name to save the file on your system.

The following text explains how these tar files were created, how to restore the NCAR LSM files, and how to run the model.

How to restore the NCAR LSM files

How to run the model on a workstation

The Unix script run_lsmv1.s, in the unix_scripts directory, will run the model for one day, using the sample input data set in the datasets directory and using a dummy atmospheric forcing. This script will have to be modified for your system and directory structure. I suggest you run this as an introduction to the model and its output.



Program Modules


SOIL TEMPERATURE

The NCAR LSM soil temperature subroutine calculates soil temperatures from one-dimensional thermal diffusion equation using apparent heat capacity to account for phase change. Soil temperature calculations depend on thermal conductivity for soil solids, thermal conductivity of dry soil, saturated volumetric soil water content of the soil, soil layer thickness, volumetric soil water content, specific heat capacity for soil solids, initial soil temperatures, heat flux into soil and snow depth at the surface.



SURFACE TEMPERATURES

The NCAR LSM surface temperature routine solves for vegetation and ground temperatures using the Newton-Raphson iteration. These temperatures must balance the surface energy budgets.

User inputs are:

  1. pressure at agcm reference height (pa)
  2. specific humidity at agcm reference height (kg/kg)
  3. temperature at agcm reference height (kelvin)
  4. atmospheric infrared (longwave) radiation (w/m**2)
  5. wind speed in eastward direction (m/s)
  6. wind speed in northward direction (m/s)
  7. reference height for agcm (m)
  8. thermal conductivity of snow/soil (w/m/kelvin)
  9. wetted fraction of canopy
  10. soil water evaporation factor (0 to 1)
  11. soil water transpiration factor (0 to 1)
  12. solar radiation absorbed by vegetation (w/m**2)
  13. solar radiation absorbed by ground (w/m**2)
  14. par absorbed per unit sunlit lai (w/m**2)
  15. par absorbed per unit shaded lai (w/m**2)
  16. true if random perturbation growth test
  17. vegetation physiology type
  18. soil temperature (kelvin)
  19. time step (s)




Go To