CICE6.6.1 is a minor update from CICE6.6.0 from November, 2024 and includes Icepack1.5.1. This release has a few significant updates including the addition of a sea-level ponds option, addition of a semi-implicit coupling scheme as needed for NASA/GEOS, and support for a MOM supergrid file. It also has several bug fixes including a fix to the outgoing longwave calculation and a fix to the ponds implementation in Icepack. There are a few enhancements, mostly for history output and coupling. Finally, the zsalinity option has been officially deprecated in this version. Note that some new pond history field diagnostics have been added but these are not supported yet for the topo ponds option. Major Changes #1020, #1036 Add new sea-level pond scheme Bug fixes #999 Fix outgoing lw for history and coupling #1002 Update Icepack to #43ead56380b to fix hocn and flushing velocity issue - changes answers #1015 Update Icepack to fix surface flux arguments and BGC bug - changes answers for BGC #1018 Remove 1:len specification in MPI boundary calls for the nvhpc compiler Enhancements #993 Add support for mom (supergrid) grid format #1000 Update Perlmutter Port, update Icepack #1001 Enable triggering restart writes at any forecast time (UFS configuration) #1003 Update derecho gnu to add coverage capability with lcov #1005 Add ability to write out one-time grid history file #1006 Update rectangular (box) configurations - changes answers for some box tests #1012 Add a semi-implicit thermodynamic coupling option, enforce mass and energy conservation for sublimation and deposition, and enable photosynthetic radiation, as needed for the GEOS model. #1013 Port to gaea #1016 Migrate dynamics thresholds to namelist and rename #1017 Deprecate zsalinity #1019 Port to blueback #1021 Update blueback for automated testing #1023 Update initial date in nuopc/cmeps driver #1025 Update method to check test jobs are completed for automated test reporting to make the method more robust. #1028 Update set_version_numbers.csh to automatically update the zenodo template, .zenodo.json. #1029 Updated the character length of stdname in the nuopc/cmeps driver #1032 Update Icepack to #cfdf8cc9cb73d5 #1034 Changed edge flux adjustment flag from l_fixed_area to l_edge_flux_adj Documentation #1007, #1027, #1030, #1032 Update Copyright, Distribution Policy, and License #1015 Update history units and conversion factors, sphinx-bibtex version #1024 Properly rename the calendar CICE uses with leap years as proleptic_gregorian rather than greogorian. #1032 Update version number to CICE6.6.1 #1034 Modifications to the documentation for C-grid remapping and edge flux adjustment method #1037 Update zenodo author list