All CLASSIC model outputs are written to netcdf files. Outputs are first specified in an xml file where the relevant metadata is assigned. Then within the CLASSIC code the variable of interest is appropriately prepared for writing at the half-hourly, daily, monthly, or annual timestep (see Editing the CLASSIC code to write the output variable).

The Output Variable Editor (OVE) is a web interface that allows a user to configure the output variables for CLASSIC. Using this interface the user can load an existing XML file and add/remove variables and variants. Once the changes are complete, the user may download an updated version of the XML configuration file.

The XML Document Structure

The XML document follows a hierarchical structure which has the variableSet as a root node. This node has a number of group child nodes, as well as attributes such as type, version and created. The group nodes have a number of variable child nodes.

The variable nodes feature several attributes (e.g. id, includeBareGround) and fields (e.g. standardName, longName, shortName, etc. They also have a collection of variant child nodes. These variants are the individual instances of the variable, which can be identified by the unique nameInCode identifier. They also have a specific timeFrequency and outputForm.

Example of xml:

    <?xml version="1.0"?>
    <variableSet type="CLASS" version="1.2" created="2018/8/7">
        <group type="class">
            <variable id="0" includeBareGround="false" dormant="false">
                <standardName>Net Shortwave Surface Radiation</standardName>
                <longName>Net downward shortwave radiation at the surface</longName>
                <shortName>rss</shortName>
                <defaultUnits>W/$m^2$</defaultUnits>
                <variant>
                    <timeFrequency>annually</timeFrequency>
                    <outputForm>grid</outputForm>
                    <nameInCode>fsstar_yr</nameInCode>
                    <units>W/$m^2$</units>
                </variant>
                <variant>
                    <timeFrequency>monthly</timeFrequency>
                    <outputForm>grid</outputForm>
                    <nameInCode>fsstar_mo</nameInCode>
                    <units>W/$m^2$</units>
                </variant>

                ...

              </variable>
          </group>
      </variableSet>

Output Variable Editor (OVE)

Opening Instructions

The Output Variable Editor folder is located in the tools folder of your local CLASS directory. Open tools/outputVariableEditor/index.html in your favorite browser and edit the output variable descriptors using the web interface.

Work flow

The various process steps are seen on the top of the page as tabs. The user first loads the existing XML document as a template, then optionally add/removes variables, then edits the variants associated with the variables, and finally generates the output XML that included the new variables and variant changes.

Load the Existing XML

Browse to an existing XML file to add/remove variables and variants. Once the file has been selected, press the "Load XML" button to load the data. An existing file is provided in the configurationFiles folder. Choose the one with the newest version number.

Add/Remove Variable

Fill in the Standard Name, Short Name, Long Name, Units fields and select a Group to classify the new variable. Select the Include bare ground check-box, if the variable includes bare ground. One may also use Add variable group to add a group or Remove variable to delete an existing variable.

Variants editor

In the variants editor, the user can find a list of all of the existing variables. Click on one to find a detailed description of the variable as well as a list of potential variants. Check the box for a particular variant you're interested in and enter the desired name in code.

Warning: Unchecking the box next to a variant and navigating to a different tab will remove any text entered in the name in code field

You may also use the search bar at the top of the window to find a specific keyword in your list of variables, and/or use the Make All Variables Dormant button to make all currently-active variables inactive.

Output XML

Once all the variable and variant changes are complete, proceed to the Output XML tab, where one can preview the newly generated XML document. Also, the website will trigger a download command, so the generated XML document will be pushed to the user for download.

Validation / Schema

A relaxNG schema is provided for validation purposes. In order to validate the XML Document, navigate to the schema folder and use the following command:

java -jar jing.jar schema_1.0.xml path/myFile.xml

where schema_1.0.xml is the current version of the schema and path/myFile.xml is the XML Document file of your choosing.

The schema will produce warnings and errors if there is any problem with the XML file, but it will not produce any output at all if everything is alright.

Manual editing

There are certain functionalities that the present interface is lacking, like editing existing variable names, removing groups, editing groups and so on. These tasks can be easily achieved by manually editing the XML input file.

Do not manually edit the id fields of the variables, as that can cause serious problems with the variables

Editing the CLASSIC code to write the output variable

Then within the CLASSIC code (prepareOutputs.f90) the variable of interest is appropriately prepared for writing at the half-hourly (prepareoutputs::class_hh_w), daily (prepareoutputs::ctem_daily_aw, prepareoutputs::class_daily_aw), monthly (prepareoutputs::ctem_monthly_aw, prepareoutputs::class_monthly_aw) or annual (prepareoutputs::ctem_annual_aw, prepareoutputs::class_annual_aw) timestep.

All writes to the netcdf file in prepareOutputs.f90 use some form of the following:

    call writeOutput1D(lonLocalIndex,latLocalIndex,'laimaxg_mo' ,timeStamp,'lai', [laimaxg_mo(i,m,:)])

Here there are two important considerations. First is the key ('laimaxg_mo' in this example). The key is used to associate this write to the appropriate netcdf output file, called the nameInCode in the xml file. The shortName (here it is 'lai') is the name of the variable in the output netcdf file. You will see the nameInCode and shortName in the xml snippet above. So your nameInCode and shortName within prepareOutputs.f90 and in your xml file must match for the proper netcdf to match to the proper model variable to be output.