NCAR Community Earth System Model

NCAR Community Earth System Model
Name	Community Earth System Model
Developer	National Center for Atmospheric Research; University Corporation for Atmospheric Research
Initial release	2010s
Programming language	Fortran, C, C++
Operating system	Unix-like
Genre	Earth system model

NCAR Community Earth System Model. The Community Earth System Model is a coupled climate model platform developed by the National Center for Atmospheric Research for simulation of atmosphere–ocean–land interactions, designed to support research by institutions such as the National Science Foundation, NASA, NOAA, U.S. Department of Energy, and international partners including the Met Office and Max Planck Institute for Meteorology. It integrates components from projects like the Community Atmosphere Model, Parallel Ocean Program, and community libraries used by groups including the Geophysical Fluid Dynamics Laboratory and the European Centre for Medium-Range Weather Forecasts to enable studies relevant to the Intergovernmental Panel on Climate Change and regional assessment bodies such as the IPCC Working Group I and national climate assessment programs.

Overview

The model is a modular, extensible framework combining atmospheric, oceanic, land surface, sea ice, and biogeochemical modules developed by teams at institutions including University of Colorado Boulder, Columbia University, Princeton University, Massachusetts Institute of Technology, and Scripps Institution of Oceanography. It supports experiments specified by protocols from consortia such as Coupled Model Intercomparison Project and interaction with analysis tools developed at National Oceanic and Atmospheric Administration, European Space Agency, and research centers like Lawrence Berkeley National Laboratory and Oak Ridge National Laboratory. The platform underpins studies tied to events such as the Paris Agreement negotiations and assessments by the United Nations Framework Convention on Climate Change.

Model Components and Architecture

The architecture couples component models: an atmosphere component originally from the Community Atmosphere Model and influences from the Goddard Institute for Space Studies model lineage; an ocean component derived from the Parallel Ocean Program and influenced by designs at the Woods Hole Oceanographic Institution; a sea ice model with roots in work at University of Washington and Scott Polar Research Institute; a land model incorporating physics from the Community Land Model and vegetation schemes researched at Rutgers University and University of Arizona; and biogeochemical modules interfacing with tracer frameworks from the National Center for Atmospheric Research and Institut Pierre-Simon Laplace. The coupler borrows concepts from middleware projects at NASA Goddard Space Flight Center and uses software practices championed by Los Alamos National Laboratory. The codebase is primarily written in Fortran with components in C and C++, using parallelization frameworks influenced by Message Passing Interface research and high-performance computing centers such as Argonne National Laboratory and NERSC.

Development History and Versions

Development traces to NCAR efforts in the late 20th century and formalized through community initiatives involving the University Corporation for Atmospheric Research and funders like the National Science Foundation and Department of Energy. Major releases aligned with international assessment cycles including CMIP5 and CMIP6, and with collaborations involving modeling centers such as the Met Office Hadley Centre, Canadian Centre for Climate Modelling and Analysis, Institut Pierre-Simon Laplace, and Max Planck Institute for Meteorology. The project governance evolved with contributions from research groups at Yale University, Harvard University, University of Michigan, Colgate University and operational agencies including NOAA Geophysical Fluid Dynamics Laboratory and European Centre for Medium-Range Weather Forecasts. Versioning and branches reflect coordinated experiments with communities represented at meetings like the American Geophysical Union and AGU Fall Meeting.

Applications and Research Uses

Scientists use the model for attribution studies tied to events such as major hurricane seasons, El Niño–Southern Oscillation episodes, and regional impacts assessed by IPCC reports and national assessments by U.S. Global Change Research Program. Research groups at Stanford University, University of California, Berkeley, ETH Zurich, Potsdam Institute for Climate Impact Research, and Tsinghua University apply it to investigate carbon cycle feedbacks, aerosol–cloud interactions explored at Imperial College London and California Institute of Technology, and cryosphere dynamics studied at British Antarctic Survey. Policy-relevant analyses connect to frameworks like the Task Force on Climate-related Financial Disclosures and scenarios used in Shared Socioeconomic Pathways developed by multidisciplinary teams including members from IIASA and OECD.

Evaluation and Performance

Evaluation of model skill is performed against observational datasets produced by programs such as Global Climate Observing System, Argo, GRACE, satellite missions like MODIS, TOPEX/Poseidon, TRMM, and reanalysis products generated by ECMWF Reanalysis and NASA MERRA. Benchmarking uses high-performance platforms at Oak Ridge Leadership Computing Facility, Argonne Leadership Computing Facility, and international supercomputing centers including PRACE nodes and systems listed by TOP500. Performance improvements have been influenced by algorithmic work at Northwestern University and software engineering practices from Carnegie Mellon University and University of Illinois Urbana-Champaign.

Community and Governance

The model is stewarded through community governance involving NCAR, the University Corporation for Atmospheric Research, and stakeholder institutions such as DOE laboratories, NOAA, and academic partners including University of California, Los Angeles and University of Maryland. User support, workshops, and training occur at venues like NCAR Mesa Lab, UCAR Community Programs, and conferences including AGU, EGU General Assembly, and specialist meetings convened by organizations like CLIVAR and Geophysical Fluid Dynamics workshops. Contributions and development are coordinated through collaborative platforms used by teams at GitHub and open science initiatives linked to Open Science Grid.

Category:Climate models