id summary reporter owner description type status priority milestone component version severity resolution keywords cc 2470 Sea-ice activation inconsistency in SBC smueller systeam "==== Context Analysis in the context of ticket #2403 revealed an inconsistency in the activation of sea-ice inclusion in the surface boundary condition (SBC) between model setups with and without AGRIF: when `key_si3` is defined, sea-ice inclusion is activated irrespective of the value of `namsbc` namelist parameter `nn_ice` in AGRIF parent domains, whereas non-AGRIF configurations require the explicit setting of `nn_ice` to an appropriate value in order to include sea-ice in the SBC. ==== Analysis When either `key_si3` or `key_cice` is defined, the value of the `nn_ice` namelist parameter is overridden in parent AGRIF domains, but remains unmodified in non-AGRIF model configurations as well as in child AGRIF domains (lines 123-132 in source:/NEMO/trunk/src/OCE/SBC/sbcmod.F90@12489). A discussion in the context of ticket #2403 confirmed that this override mechanism has been deliberately deactivated in child AGRIF domains and in non-AGRIF configurations (cf. [1242] and [12063], respectively) and suggested that it should be removed for parent AGRIF domains also. ==== Recommendation The complete removal of lines 123-132 of source:/NEMO/trunk/src/OCE/SBC/sbcmod.F90@12489 is recommended in order to remove the sea-ice activation inconsistency in SBC. In addition, the explicit setting of `nn_ice = 2` in the namelists for the parent AGRIF domains in AGRIF-enabled configurations with sea ice in source:/NEMO/trunk/cfgs and source:/NEMO/trunk/tests should be verified. Further, comments that refer to the `nn_ice` override mechanism in some of the namelist files for the configurations in source:/NEMO/trunk/cfgs and source:/NEMO/trunk/tests should be adjusted to bring them in line with the actual implementation of the sea-ice activation mechanism in SBC. " Defect closed low SBC trunk minor fixed SBC, AGRIF