Emergence of the Earth System Modeling Framework

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Emergence of the Earth System Modeling Framework
NCAR/LANL CCSM
Climate
GFDL FMS Suite
Data Assimilation
NASA GMAO Analysis
NSIPP Seasonal Forecast
MITgcm
Weather

Cecelia DeLuca Symposium on the 50th Anniversary
of ONWP
NCEP Forecast
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Motivation
In NWP, seasonal prediction and climate
research... increased emphasis on detailed
representation of individual physical processes
requires many teams of specialists to contribute
components to an overall modeling system In
computing technology... increase in hardware and
software complexity in high-performance
computing, shift toward the use of scalable
computing architectures In software
development of frameworks (integrated
libraries), such as the GFDL Flexible Modeling
System (FMS) and Goddard Earth Modeling System
(GEMS) that encourage software reuse and
interoperability The ESMF is a community effort
to tame the complexity of models and the
computing environment. It leverages, unifies and
extends existing software frameworks, breaking
down institutional barriers and creating new
opportunities for scientific contribution and
collaboration.
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ESMF Project Description

• GOALS To increase software reuse,
  interoperability, ease of use and performance
  portability in climate, weather, and data
  assimilation applications
• PRODUCTS
• Core framework Software for coupling
  geophysical components and utilities for building
  components
• Applications Deployment of the ESMF in 15 of
  the nations leading climate and weather models,
  assembly of 8 new science-motivated applications
• METRICS
• RESOURCES and TIMELINE 9.8M from NASA ESTO
  over 3 years, starting February 2002 Ongoing
  support from the National Science Foundation

Reuse Interoperability Ease of Adoption Performance
15 applications use ESMF component coupling services and 3 utilities 8 new applications comprised of never-before coupled components 2 codes adopt ESMF with lt 2 lines of code changed, or within 120 FTE-hours No more than 10 overhead in time to solution, no degradation in scaling
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ESMF Architecture

• ESMF provides an environment for assembling
  geophysical components into applications, with
  support for ensembles and hierarchies.
• ESMF provides a toolkit that components use to
• increase interoperability
• improve performance portability
• abstract common services

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Hierarchies and Ensembles

• ESMF encourages applications to be assembled
  hierarchically and intuitively
• Coupling interfaces are standard at each layer
• Components can be used in different contexts

ESMF supports ensembles with multiple instances
of components running sequentially (and soon,
concurrently)
Ensemble Forecast
Seasonal Forecast
assim_atm
sea ice
ocean
assim_atm
assim_atm
assim_atm
assim
atmland
atm
land
coupler
physics
dycore
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ESMF In More Detail

• Fortran interfaces (mixed-language
  implementation)
• Multi-platform support (SGI, Compaq, IBM, Linux -
  Intel, PGI, NAG, Absoft)
• Clear, simple hierarchy of data objects (arrays,
  fields, bundles of fields, components) for
  developing modeling codes
• Toolkits for communications (redist, halo, etc.),
  time management, error handling and logging,
  resource files, IO
• Regridding library is on-line, parallelized
  version of SCRIP from LANL
• Tools for multithreading, cache blocking, and
  load balancing integrated into the architecture
  development has been highly performance-aware!
• Data objects and toolkits have consistent naming
  and behavior across the framework

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The Benefits

• Standard interfaces to modeling components
  promote increased interoperability between
  centers, faster movement of modeling components
  from research to operations
• The ability to construct models hierarchically
  enables developers to add new modeling components
  more systematically and easily, facilitates
  development of complex coupled systems
• Multi-use objects mean that the same data
  structure can carry information about
  decomposition, communications, IO, coupling
  this makes code smaller and simpler, and
  therefore less bug-prone and easier to maintain
• Shared utilities encourage efficient code
  development, higher quality tools, more robust
  codes

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Open Development

• Open source
• Currently 800 unit tests, 15 system tests are
  bundled with the ESMF distribution, can be run in
  non-exhaustive or exhaustive modes
• Results of nightly tests on many platforms are
  accessible on a Test and Validation webpage
• Test coverage, lines of code, requirements status
  are available on a Metrics webpage
• Exhaustive Reference Manual, including design and
  implementation notes, is available on a Downloads
  and Documentation webpage
• Development is designed to allow users clear
  visibility into the workings and status of the
  system, to allow users to perform their own
  diagnostics, and to encourage community ownership

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ESMF Key Accomplishments

• Public delivery of prototype ESMF v1.0 in May
  2003
• Monthly ESMF internal releases with steadily
  increasing functionality
• Completion of first 3 coupling demonstrations
  using ESMF in March 2004
• NCAR CAM with NCEP SSI
• NCAR CAM with MITgcm ocean
• GFDL B-grid atmosphere with MITgcm ocean
• All codes above running as ESMF components and
  coupled using the framework, codes available from
  Applications link on website
• Other codes running as ESMF components MOM4,
  GEOS-5
• Less than 2 lines of source code change
• On track for delivery of ESMF v2.0 on 23 June
  2004
• 3rd Community Meeting to be held on 15 July 2004
  at NCAR

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Interoperability Experiments Completed
3 NCAR Community Atmospheric Model (CAM) coupled
to MITgcm ocean Atmosphere, ocean, and coupler
are set up as ESMF components Uses ESMF
regridding tools
1 GFDL B-grid atmosphere coupled to MITgcm
ocean Atmosphere, ocean, and coupler are set up
as ESMF components Uses ESMF regridding tools
2
Temperature SSI import Temperature SSI
export Temperature difference
NCAR Community Atmospheric Model (CAM) coupled to
NCEP Spectral Statistical Interpolation (SSI)
System, both set up as ESMF components Experiment
utilizes same observational stream used
operationally at NCEP
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Next Steps

• Integration with data archives and metadata
  standardization efforts, anticipate collaboration
  with Earth System Grid (ESG) and European
  infrastructure project PRISM
• Integration with scientific model intercomparison
  projects (MIPs), anticipate collaboration with
  the Program for Climate Model Diagnosis and
  Intercomparison (PCMDI), other community efforts
• Integration with visualization and diagnostic
  tools for end-to-end modeling support, anticipate
  collaboration with the Earth Science Portal (ESP)
• ESMF vision for the future articulated in
  multi-agency white paper on the Publications and
  Talks webpage

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More Information

• ESMF website http//www.esmf.ucar.edu
• 3rd Community Meeting on 15 July at NCAR