NCAR Land Surface Model (NCAR LSM version 1)
The NCAR LSM is available for all interested users. Please
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
- There are four directories
( datasets , model ,
technote , unix_scripts )
corresponding to the four tar files
- Each directory has been tarred with the Unix command
(using model as an example): tar cf model.tar model
- Each tar file has been compressed with the Unix command
(using model.tar as an example): compress model.tar
- This creates the four compressed tar files:
datasets.tar.Z , model.tar.Z ,
technote.tar.Z , unix_scripts.tar.Z
- These files must be uncompressed with the Unix command
(using model.tar.Z as an example): uncompress model.tar.Z
- Each directory must be restored from its tar file with the
Unix command (using model.tar as an example): tar xf model.tar
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.
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.
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:
- pressure at agcm reference height (pa)
- specific humidity at agcm reference height (kg/kg)
- temperature at agcm reference height (kelvin)
- atmospheric infrared (longwave) radiation (w/m**2)
- wind speed in eastward direction (m/s)
- wind speed in northward direction (m/s)
- reference height for agcm (m)
- thermal conductivity of snow/soil (w/m/kelvin)
- wetted fraction of canopy
- soil water evaporation factor (0 to 1)
- soil water transpiration factor (0 to 1)
- solar radiation absorbed by vegetation (w/m**2)
- solar radiation absorbed by ground (w/m**2)
- par absorbed per unit sunlit lai (w/m**2)
- par absorbed per unit shaded lai (w/m**2)
- true if random perturbation growth test
- vegetation physiology type
- soil temperature (kelvin)
- time step (s)