change_namelist_clm

# reference
http://www.cesm.ucar.edu/models/ccsm4.0/clm/models/lnd/clm/doc/UsersGuide/x1327.html

default value for dtime DTIME = 1800 second half-hourly
# remove all history fields
hist_empty_htapes = .true.
 hist_fincl1 = 'TG', 'TV', 'FSA'
  hist_fincl1 = 'COSZEN', 'DECL'
 hist_fexcl1 = 'TG', 'TV', 'TSOI', 'H2OSOI'
 
 # specify the output frequency
Positive value means the output frequency is the number of model steps between output.
Negative value means the output frequency is the absolute value in hours given (i.e -1 would mean an hour and -24 would mean a full day). Daily (-24) is the default value for all auxiliary files.
Zero means the output frequency is monthly. This is the default for the primary history files.