create crosswalk mapping between TopoFlow and DSSAT

[alee]

Identify potential variables of interest and map inputs / outputs between the TopoFlow hydrology model and the DSSAT crop model via BMI

@chporter suggested starting with following variables from DSSAT: ICASA_Subset.xlsx

More broadly, these include:

• ICASA variables: http://www.tinyurl.com/icasa-mvl
• CSDMS standard names registry http://csdms.colorado.edu/wiki/CSDMS_Standard_Names and https://github.com/csdms/standard_names_registry
• CSDMS standard names python module for interacting with the standard names registry: https://github.com/csdms/standard_names

[alee]

ICASA_Subset.xlsx

[alee]

Hydrology model generates DSSAT weather station files with custom RAIN values. These generated WTH weather station files must be referenced by the MZX file and executed via dssat A <MZX file>