CCPP Framework Meeting Minutes 2019 11 21

Reschedule meeting from Dec 5

• Thursdays 4-5pm

Scope of the meeting

• initially only ccpp-framework
• physics unification efforts between NCAR and NOAA

RRTMG unification

• GFS RRTMG in the repository
• Man Zhang is currently adding the WRF/HWRF RRTMG version (which of the three WRF versions?)
• Mike/John from AER will help us unifying the different versions
• but operational constraints from NOAA (and NCAR?)
• there will be differences that are required by the users
• below the driver, the core code can hopefully (!) be same
• where does RRTMGP fit into this? is this slated to replace RRTMG at NOAA in about two years? since this is a complete rewrite of the RRTMG package, this will likely remain a separate package
• the goal of Mike and John is to add the cloud overlap additions from the HWRF version to the GFS version; they don't know CCPP yet - we should prepare a short presentation for the Dec 3 meeting (conceptual and motivation)
• note: from previous experience, making the actual scheme CCPP-compliant is easy, the problem is the interstitial code around it ("turning the atmospheric state into a radiation problem")
• need a repository for this collaboration (authoritative repository for RRTMG) - escomp seems to be a good place (independent of any organization)

Progress WRF/MPAS+CCPP:

• target the actual scheme one or two levels below the WRF/MPAS driver, which has (horizontal_dimension,vertical_dimension) for adding the CCPP hooks
• keep the layers above for current direct calls in WRF/MPAS
• these layers need to be replaced with other/interstitial code in the host models
• done already for YSU scheme

Timeline:

• around March will be a SIMA meeting; from end of the year until about March would be a good time for MMM to work with the rest of us; before that we don't really need the escomp repository