Abstract
Abstract. The Community Earth System Model (CESM1), maintained by the United States National Centre for Atmospheric Research (NCAR) is connected with the Modular Earth Submodel System (MESSy). For the MESSy user community, this offers many new possibilities. The option to use the Community Atmosphere Model (CAM) atmospheric dynamical cores, especially the state-of-the-art spectral element (SE) core, as an alternative to the ECHAM5 spectral transform dynamical core will provide scientific and computational advances for atmospheric chemistry and climate modelling with MESSy. The well-established finite volume core from CESM1(CAM) is also made available. This offers the possibility to compare three different atmospheric dynamical cores within MESSy. Additionally, the CESM1 land, river, sea ice, glaciers and ocean component models can be used in CESM1/MESSy simulations, allowing the use of MESSy as a comprehensive Earth system model (ESM). For CESM1/MESSy set-ups, the MESSy process and diagnostic submodels for atmospheric physics and chemistry are used together with one of the CESM1(CAM) dynamical cores; the generic (infrastructure) submodels support the atmospheric model component. The other CESM1 component models, as well as the coupling between them, use the original CESM1 infrastructure code and libraries; moreover, in future developments these can also be replaced by the MESSy framework. Here, we describe the structure and capabilities of CESM1/MESSy, document the code changes in CESM1 and MESSy, and introduce several simulations as example applications of the system. The Supplements provide further comparisons with the ECHAM5/MESSy atmospheric chemistry (EMAC) model and document the technical aspects of the connection in detail.
Highlights
Increasing scientific and societal interest in understanding and forecasting the state of the atmosphere, oceans, land and ice has led to the development of Earth system models (ESMs)
While CAM5 provides four different cores, we describe only the cores implemented in CESM1/Modular Earth Submodel System (MESSy), the CAM5 default finite volume (FV) core and the new spectral element (SE) core
As the CESM1/MESSy simulations are free running, different synoptic meteorologies lead to some differences on timescales of weeks, but overall the expected annual variations are present in all three simulations
Summary
Increasing scientific and societal interest in understanding and forecasting the state of the atmosphere, oceans, land and ice has led to the development of Earth system models (ESMs). ECHAM5/MESSy atmospheric chemistry (EMAC) model, the base model ECHAM5 provides only the dynamical core, including advection; all physics parametrizations have been recoded or replaced by submodels, and infrastructure code has been recoded or replaced by generic infrastructure submodels. That CESM1 provides a much larger number of process descriptions of all components of the Earth than ECHAM5 This means that much larger portions of the CESM1 code are still used in a CESM1/MESSy simulation. We present test simulations using MESSy atmospheric physics and chemistry submodels for the atmosphere, with execution and data handling done by MESSy generic interface submodels, using one of the CESM1(CAM5) atmospheric dynamical cores, and CESM1 component models for ocean, land, ice and rivers. For MESSy users, CESM1/MESSy offers additional state-of-the art atmospheric dynamical cores, as well as the ability to couple with other component models. For CESM users, CESM1/MESSy offers the opportunity to use an independent physics and chemistry suite, replacing the CAM physics and chemistry
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
