# WRF I/O: Can any variable be output into the wrfout file-stream?

This question is related to the WRF (Weather Research and Forecasting) Model

I read somewhere that a variable one wants to output, needs to be defined as state variable in the Registry like this (defines the variable QFX, which already is in the output file)

state    real  QFX              ij      misc        1         -      rh       "QFX"                   "UPWARD MOISTURE FLUX AT THE SURFACE"          "kg m-2 s-1"


where "h" in "rh" stands for "history", i.e. the output in the wrfout_d01_.... NETCDF standard output history files.

Can I add any variable as state variable?

For example EETA (transpiration), which is defined in the module_sf_ruclsm. (at the physics layer). Gill WRF I/O states "Local variables inside of physics packages are not controlled by the Registry". So do I need to initialize EETA to the variables in module_surface_driver.F?

I copied the line from QFX and changed the variable name to EETA, but it failed when executing wrf.exe in ./frame/module_domain.F on line 1174

WRITE(mess,*)'W A R N I N G : Unable to modify mask for ',TRIM(lookee),&

iofields_filename = "myoutfields.txt” (MAXDOM)