Implementation of the Community Earth System Model (CESM) version 1.2.1 as a new base model into version 2.50 of the MESSy framework

摘要

The Community Earth System Model (CESM1), maintained by the United States National Centre for Atmospheric Research (NCAR) is connectedwith the Modular Earth Submodel System (MESSy). For the MESSy usercommunity, this offers many new possibilities. The option to use theCommunity Atmosphere Model (CAM) atmospheric dynamical cores,especially the state-of-the-art spectral element (SE) core, as an alternative to the ECHAM5 spectral transformdynamical core will provide scientific and computational advances foratmospheric chemistry and climate modelling with MESSy.The well-established finite volume core fromCESM1(CAM) is also made available. This offers the possibility tocompare three different atmospheric dynamical cores withinMESSy. Additionally, the CESM1 land, river, sea ice, glaciers andocean component models can be used in CESM1/MESSy simulations,allowing the use of MESSy as a?comprehensive Earth system model (ESM). ForCESM1/MESSy set-ups, the MESSy process and diagnostic submodels foratmospheric physics and chemistry are used together with one of theCESM1(CAM) dynamical cores; the generic (infrastructure) submodelssupport the atmospheric model component. The other CESM1 componentmodels, as well as the coupling between them, use the original CESM1infrastructure code and libraries; moreover, in future developmentsthese can also be replaced by the MESSy framework. Here, we describethe structure and capabilities of CESM1/MESSy, document the codechanges in CESM1 and MESSy, and introduce several simulations asexample applications of the system. The Supplements provide furthercomparisons with the ECHAM5/MESSy atmospheric chemistry (EMAC) modeland document the technical aspects of the connection in detail.