Century Model Parameters

Model Parameter Sets

Parameter Files

Model parameter files in text format (*.100 files) contain multiple sets of parameters (except fixed parameters, which contain only one set per file). Each parameter set begins with a line that contains a name and a description, such as:

BARL60     barley 60% straw removed

The name of the parameter set is the text at the start of the line before the first whitespace from the left (here, BARL60). The text after the first whitespace is the description. The maximum length of the parameter set name is 10 characters. The maximum length of the parameter set description is 80 characters. The amount of white space after the name is ignored.

Comment lines can be inserted anywhere in the file. Each comment line should begin with one of the following symbols: # ! ; Comments are useful for describing the source of the parameter values, as well as who and when the parameters were edited.

Customized Parameter Sets

You can create and use a custom set of parameters in a directory related to your simulation work area. If you are doing multiple simulations that will use your custom parameter sets, create separate directory to hold these files. Otherwise, you can put these custom *.100 files in the same directory as your simulation files. For simulations of multiple site and/or multiple management schedule files, the following directory structure is useful for organizing a large number of files:

|-- 100
|-- sites
|-- mgmt
`-- results

A default set of model parameter files is provided with the Century5 source code in the path Ecosystem/Century5/bin/parameters/Monthly or Ecosystem/Century5/bin/parameters/Daily for Century5 and DayCent5, respectively. In your work directory create a text file named crop.100 or tree.100 (use the same file name as the default parameter set file). In your text editor, open the file of the same name in the default parameter set directory. Copy (do not cut!) the parameter set which you want to modify, and paste that set into your new crop or tree file. Then modify the parameter values as you need to.

Specify the command-line option -pp to tell Century5 the path to these custom files. If you provide the -pp option, any parameter files in this path will be searched before the default parameters files. You can use the same parameter set name in your custom parameter set that is used in the default parameters files, and the latter set will be ignored.

For example, if you are running a Century5 simulation from the current directory which also contains your custom crop.100 file, your command line would be similar to this:

century5 -s MySite -m MyMgmt -o results/MySite_MyMgmt -pp . [more options follow]

where the dot in "-pp ." means "the current directory".

See Also

Site Parameters
About the Model Internal Parameterization
Running Century and CMI with Command-Line Options