 data model, the land and snow modes are treated completely 
independently as if there were two models.

datamode = "NULL"
  NULL is always a valid option and means no data will be generated.  
  Turns off the data model as a provider of data to the coupler.  The
  ice_present flag will be set to false and the coupler will assume no
  exchange of data to or from the data model.
dataMode = "COPYALL"
  Copies all fields directly from the input data streams Any required
  fields not found on an input stream wi