Input Data

All active and data components use input datasets. A local disk needs $DIN_LOC_ROOT to be populated with input data in order to run CESMwith these components. For all machines, input data is provided as part of the release via data from the CESM subversion input data server. However, on supported machines (and some non-supported machines), data already exists in the default local filesystem input data area as specified by $DIN_LOC_ROOT (see below).

Input data is handled by the build process as follows:

• The buildnml scripts in Buildconf/i create listings of required component input datasets in the Buildconf/$component.input_data_list files.
• $CASE.build checks for the presence of the required input data files in the root directory $DIN_LOC_ROOT. If all required data sets are found on local disk, then the build can proceed.
• If any of the required input data sets are not found, the build script will abort and the files that are missing will be listed. At this point, you must obtain the required data from the input data server using check_input_data with the -export option.

The env_run.xml variables DIN_LOC_ROOT and DIN_LOC_ROOT_CLMFORC determine where you should expect input data to reside on local disk. See the input data variables.

User-created input data

If you want to use new user-created dataset(s) and give these dataset(s) names that are different than the names in $DIN_LOC_ROOT, we recommend using the script link_dirtree in the directory $CCSMROOT/scripts. link_dirtree creates a virtual copy of the input data directory by linking one directory tree to another. The full directory structure of the original directory is duplicated and the files are linked. To use this script, use the -h optiion for usage.

> cd $CCSMROOT/scripts 
> ./link_dirtree -h

link_dirtree can be conveniently used to generate the equivalent of a local copy of $DIN_LOC_ROOT which can then be populated with user-specified input datasets. For example, you can first generate a virtual copy of $DIN_LOC_ROOT in /user/home/newdata with the following command:

> link_dirtree $DIN_LOC_ROOT /user/home/newdata

then incorporate the new dataset(s) directly into the appropriate directory in /user/home/newdata.

Using the input data server

The script $CASEROOT/check_input_data determines if the required data files for the case exist on local disk in the appropriate subdirectory of $DIN_LOC_ROOT. If any of the required datasets do not exist locally, check_input_data provides the capability for downloading them to the $DIN_LOC_ROOT directory hierarchy via interaction with the input data server. You can independently verify that the required data is present locally by using the following commands:

> cd $CASEROOT
> check_input_data -help
> check_input_data -inputdata $DIN_LOC_ROOT -check

If input data sets are missing, you must obtain the datasets from the input data server: ` > cd $CASEROOT > check_input_data -inputdata $DIN_LOC_ROOT -export `` Required data files not on local disk will be downloaded through interaction with the Subversion input data server. These will be placed in the appropriate subdirectory of ``$DIN_LOC_ROOT. For what to expect when interacting with a Subversion repository, see downloading input data.