OBS and ASM developments (2022 WP)

Development description

Met Office developments to OBS and ASM from the 2022 WP.

The biggest of these is adapting the OBS interface to be more generic, allowing more flexibility in terms of inputs and options, and making it easier to add new (e.g. biogeochemical) variables.

Additional developments include adaptation to work with TEOS10, adaptation to work with SI3, addition of surface velocity and sea ice thickness, and some minor bug fixes.

Code implementation

Developments for the generic OBS interface can be seen in a UKMO branch of v4.0.4: https://forge.ipsl.jussieu.fr/nemo/changeset?reponame=&new=15497%40NEMO%2Fbranches%2FUKMO%2FNEMO_4.0.4_generic_obs&old=15089%40NEMO%2Fbranches%2FUKMO%2FNEMO_4.0.4_generic_obs

The existing &namobs namelist, containing all OBS options, will be replaced with a shorter high-level &namobs, and multiple &namobs_dta namelists for each observation group, similar to the BDY interface. A new obs_group_def.F90 will be created to deal with this, and alterations will be made to diaobs.F90 and other modules.

Documentation updates

The documentation will be updated to reflect the new interface.