As a consequence of the more streamlined release model we are now ready with a new release of GOTM - version 5.2. Updating the stable version implies a new version for the development branch as well - now 5.3.

As a user the following step must be taken in order to use the new stable version of the code.

• Check out the new branch - v5.2 - of the GOTM source code
• If you are using editscenario and related .xml-file to keep track of your configuration the version description on the first line of the .xml file must be updated to gotm-5.2.

Update to new versions have been done for all the standard test cases provided with GOTM.

In this release two new features has been implemented as described below.

New features

• Hot-start facility - developed in the PROGNOS project and further supported by JRC.
• Option to read in longwave back-radiation instead of calculating - funded by Don Pierson/Erken
• We have also added 3 new test-cases - two for the Mediterranean, one for the Black Sea and updated the gotland case.

Hot-start (or restart) allow to split a simulation in two or more time-chunks. GOTM will at the end of a simulation write the state of the model to a NetCDF- formatted file - restart.nc. This file can be used to provide initial conditions at a subsequent simulation. The feature is controlled via the namelist variable restart_offline by setting it to true. There are different use-cases for the hot-start facility. One involves spinning up GOTM in physics only mode and when the physics is in balance enable bio-geochemistry. The restart.nc file from the spin-up run does not contain any bio-geochemical variables - on the other hand - when the bio-geochemical is started the full state is a combination of physical and biogeochemical state-variables. In this case the variable restart_allow_missing_variable must be set to .true.. Missing variables in restart.nc will be reported to the screen - but the simulation will continue. The default setting of restart_allow_missing_variable is .false. as it is the safer setting.

The lake people have for a while asked for an option to read in longwave back- radiation instead of calculating it as part of the normal air-sea flux calculation. This feature has been implemented.

Please have a look at the planned roadmap.