CICE version 6.0.0 is released with Icepack version 1.1.0. Icepack contains the column physics within CICE, first released as an independent software package in February 2018. Because the code refactoring associated with Icepack introduced significant differences with the previous CICE release (v5.1.2), we created an "alpha" version of CICE v6 in March 2018 while enhancements for the full v6 release were completed.
Since the v6.0.0.alpha release, we updated Icepack to version 1.1.0, implemented dynamic allocation for most arrays, enhanced all rheology options (EVP, rEVP, EAP), simplified the initialization procedure for tracers, added support for CMIP6 history output, improved the quality control and compliance tests, added new test configurations to the test suites, and automated basic testing using Travis CI. This release also includes many other improvements since version 5.1.2, most notably a new landfast-ice parameterization with tensile strength, and full vertical biogeochemistry with shortwave feedback on sea ice physics. The source code and forcing data directories have been restructured to allow extensions for other sea ice model components, and we implemented a flexible, extensible, robust interface between Icepack and the sea ice model driver. The code, scripts, development procedures and tasks/issues are documented online, and automated test reporting is available.