1 NEMS and NGGPS integration Presented By: Hendrik Tolman (NWS/NCEP/EMC) Contributors: EMC senior staff

NEMS and NGGPS integration NEMS is the infrastructure we intend to use to manage a unified coupled modeling suite efficiently. In NEMS, we adopt a new dycore, not a full model. –More rapid transition to operations, as many aspects of the operational models remain the same. In NEMS, we (intend to) deal with physics in a modular version. Modular approach allows to –Do unified modeling, but if necessary, –have various cores and physics packages. –Maintenance of packages is much cheaper than of full models, and therefore –NEMS in principle allow for cheaper multi-model approaches too. 2

3 NGGPS and NEMS / ESMF Modular modeling, using ESMF to modularize elements in fully coupled unified global model ( + ionosphere, ecosystems, …… ) Presently available dycores are GSM, NAM, FIM. Physics interface v1.0 delivered June 2015.

4 NGGPS physics Atmosphere Model including Dynamics  t, u, v, w, T, , p, z, q x, c x, a x destaggered Tendencies and Updates Init Mode Dynamical equations, advection, horizontal mixing, diffusion. Radiation Deep and Shallow Cumulus Surface Layer PBL and Vertical Mixing Micro- physics Modified Kalnay Rules Layer NUOPC Physics Driver Schematic Output Diagnostics fields rates budgets others Atmospheric Physics Driver (init, run, finalize modes) Initialize Physics Tables and Databases Finalize Mode. standard interface for model physics

5 System Evolution Over the Next 5 Years Common Physics Interface V1.0 delivered June 2015

6 Why System(s) are Operational  Top 3 System Performance Strengths Modularity allows for coupled modeling and development of component models both to be (relatively) simple. Allows for unified modeling approach, but also allows for various component models to be interchanged in a relatively simple way. Update / addition of component models in principle does not require change in infrastructure, making R2O in principle much more efficient.  Top 3 System Performance Challenges Efficiency / simplicity of system (compare, e.g., WRF and CESM) Limit to as unified a model as possible. Modular approach is associate with “weak” coupling, unlike fully integrated component models. The modular approach may prove inefficient on exoscale computing.

7 Top 3 Things We Need From the UMAC 1.Endorsement of modular approach. ESMF  NUOPC  NEMS 2.Community involvement of development. Community modeling approach, Reassess / develop requirements. Assessment of strengths and weaknesses. 3.How to involve existing community better USA: e.g., CESM Europe ?