These UKCA specific notes should be read in conjunction with the general release notes which are available on the collaboration Twiki. These notes cover changes which have a significant impact on UKCA developers and cover these changes in more detail than the standard release notes.
UM 8.5
The first of a series of changes to support the transition from the UMUI to Rose were made at this release. At present, most users should continue to use the UMUI at vn8.5 and vn8.6. Version 9.0 will retire the UMUI and all users will have to use Rose from then on. The changes discussed below do not have a significant impact on most users but some are important for those developing new code, especially for chemistry schemes which have not yet been lodged. This is an overview of the changes, if you need more information or have any problems at 8.5+ please contact Nick Savage who made the changes.
- All ukca related input logicals are now read in from the run_ukca namelist including l_ukca, l_ukca_radaer, l_ukca_aie1, l_ukca_aie2 which were previously in nlstcatm.
- The run_ukca namelist has moved from the CNTLATM file to SHARED.
- All namelist variables are now given an initial value when declared. See ukca_option_mod.F90. Any new namelist variables being added must have an initial value and this should normally be false for logicals and the Missing Data value for integers and reals.
Chemistry namelist changes
- The namelists no longer contain a separate logical for each chemistry scheme e.g. l_ukca_trop, l_strat etc. These are all replaced by a single integer i_ukca_chem. The meaning of each value of i_ukca_chem is set up in the new module ukca_chem_schemes_mod.F90
- The original logicals still exist inside the code and are set depending on the value of i_ukca_chem in the new subroutine ukca_setup_chem_mod.F90. It is planned to completely remove the chemistry scheme logicals and replace them with i_ukca_chem at a later date.
- The number of reactions, number of tracers etc (jpctr, jpspec, jpbk, jptk, jppj, jphk, jpnr, jpdd, jpdw) have also been removed from the namelists and are set up in ukca_setup_chem_mod.F90
- If adding a new chemistry scheme, simpler hand edits can now be used as there are fewer items to set, but developers must add a magic number for the new chemistry scheme in ukca_chem_schemes_mod.F90 and set the number of reactions etc in ukca_setup_chem_mod.F90. However, the active tracers still have to be set via a handedit to the tc_ukca 150 element array. This will change at 8.6 or 9.0.
Photolysis namelist change
The separate logicals for the photolysis schemes have been retired and replaced with a single logical i_ukca_photol with magic numbers defined in ukca_photo_scheme_mod.F90
GLOMAP-mode namelist changes
A number of redundant items have been removed from the namelist which either could not be set from the UMUI or had no effect inside the code.
New Rose metadata
As well as the namelist changes described above, please also note that Rose metadata (used to control the GUI which will replace the UMUI) have been set up. These are held in rose-meta/um-atmos/HEAD/rose-meta.conf and any new namelist items to be lodged will also require this metadata. Please consult Nick Savage for help.
Diagnostics changes
The other major change at this version was the moving of all UKCA chemistry diagnostics into section 50. This means that section 34 only contains prognostic variables and helps to create space to increase the number of available tracers at a later date. Any new diagnostics should be added to section 50. Also note that if you plan to lodge a new diagnostic, you should request a STASH code for it to prevent future conflicts.
IFDEF retirement
As part of wider changes in the UM, the IFDEFs at the top of each routine have been removed from the code and must not be included in any new subroutines. i.e. #if defined(A34_1A) at the top and #endif at the bottom must be removed.
