Clarification of lower boundary conditions
Currently, with soil, lower Dirichlet boundary conditions can be imposed on the soil/snow column by setting SNP_SOIL=true and SOIL_FLUX=false. Thereby, CurrentMeteo.ts0 is assigned MeteoData::TSG. This procedure is not transparent though.
Accordingly, we should aim at having two input fields MeteoData::TB(ase) and MeteoData::TG(round). The prescribed temperature at the base of the snow/soil column would then be given by CurrentMeteo.tb in SNOWPACK (instead of CurrentMeteo.ts0). If both MeteoData::TB and MeteoData::TG are given, we will also have differing CurrentMeteo.tb and CurrentMeteo.tg in SNOWPACK, otherwise these two variables will be equal. Finally, MeteoData::TSG would be dropped [or moved to TGS= temperature ground surface].
Accordingly changes are required in MeteoIO, Alpine3D (3 lines, SnowpackInterfaceWorker), SNOWPACK, and INIshell.