If ice_freq_opt is not 'never', the code will create ice whenever the ocean temperature drops below freezing at levels higher then kmxice. This ice formation will be computed at frequencies determined by the ice_freq in ice_freq_opt units. If the model is being run in coupled mode, ice_freq_opt should be set to 'coupled' to compute ice formation on coupling timesteps. In coupled mode, the heat and water fluxes associated with ice formation are saved and sent to the flux coupler for use in the ice model.

Table: Ice formation namelist
&ice_nml LANL default CESM1 default Valid values parameters used to emulate sea-ice
ice_freq_opt'never''coupled''never', 'coupled', 'nyear', 'nmonth', 'nday', 'nhour', 'nsecond', 'nstep'frequency units for computing ice formation
ice_freq1100000integerfrequency in above units for computing ice formation
kmxice11[1,1-km]compute ice formation above this vertical level
lactive_iceN/Aautomatically prefilled by CESM1 scripts.true., .false.if .true., model is running with CESM1 active ice model
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