POP exiting... unknown field requested for history file

[jenny@misu_su_se]

I would like to write TAUX and TAUY to POP history files once every day. Therefore I add the lines

2220 'TAUX ' 'Windstress in grid-x direction ' 'dyne/centimeter^2 '
2220 'TAUY ' 'Windstress in grid-y direction ' 'dyne/centimeter^2 '

to the file SourceMods/src.pop/gx1v3_history_contents in my CASEROOT directory.

POP does not like this though, it exits with the message (tail of ocn.log.yymmdd-hhmmss file):

Document Namelist Parameters:
============================

&HISTORY_NML
HISTORY_FREQ_OPT = nday ,
HISTORY_FREQ = 1,
HISTORY_OUTFILE = /nobackup/skb1/sm_jenbr/ccsm3/scratch//b30.104.1m/ocn/hist/b30.104.1m.pop.hs ,
HISTORY_CONTENTS = /nobackup/skb1/sm_jenbr/ccsm3/scratch//b30.104.1m/ocn/input/history_contents ,
LHISTORY_USE_NCDF = T
/

------------------------------------------------------------------------

POP exiting...
unknown field requested for history file

------------------------------------------------------------------------

These variables are part of the tavg files (specified in SourceMods/src.pop/gx1v3_tavg_contents), why are they not known for history file printouts?

I would be most grateful for some insight!

Jenny