Components in the Earth System Modeling Framework

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Components in the Earth System Modeling Framework
GFDL FMS Suite
MITgcm

NASA GSFC PSAS
NCEP Forecast
NSIPP Seasonal Forecast
NCAR/LANL CCSM
Nancy Collins, NCAR Components Workshop,
Princeton, NJ
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Outline

• ESMF Component Design Principles
• ESMF Component User Environments
• ESMF Component Details

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ESMF Project Overview

• GOAL To increase software reuse,
  interoperability, ease of use and performance
  portability in climate, weather, and data
  assimilation applications
• PRODUCTS
• Coupling superstructure and utility
  infrastructure software
• Synthetic code suite for validation and
  demonstration
• Set of 15 ESMF-compliant applications (including
  CCSM, WRF, GFDL models MIT, NCEP and NASA data
  assimilation systems)
• Set of 8 interoperability experiments
• RESOURCES 10.1M over 3 years from NASA Earth
  Science Technology Office

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ESMF Class Structure
ApplicationComponent
GriddedComponent
CouplerComponent
Superstructure
State
Bundle
Regrid
Infrastructure
Field
Grid
PhysGrid
DistGrid
F90
Data
Communications
Layout
Array
Comm
Route
C
MachineModel
Utilities TimeMgr, Config, LogErr, I/O etc.
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Design PrinciplesScalable Applications
Since each ESMF application is also a component,
entire ESMF applications may be treated as
Gridded Components and nested within larger
applications.
climate_comp
Example atmospheric application containing
multiple coupled components within a larger
climate application
ocn2atm_coupler
ocn_comp
atm_comp
phys2dyn_coupler
atm_phys
atm_dyn
PE
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Design PrinciplesLocal Communication
All inter-component communication within ESMF is
local.
climate_comp
This meansCoupler Components must be defined
on the union of the PEs of all the components
that they couple. In this example, in order to
send data from the ocean component to the
atmosphere, the Coupler mediates the send.
atm2ocn _coupler
ocn_comp
atm_comp
phys2dyn_coupler
atm_phys
atm_dyn
PE
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Design PrinciplesImport/Export States
Gridded Components do not have access to the
internals of other Gridded Components. They have
2 options for exchanging data with other
Components the first is to receive Import and
Export States as arguments.
States contain flags for is required,
isvalid, is ready, etc.
coupler
ocn_component subroutine ocn_run(comp,
ImportState,ExportState, Clock, rc)
atm_component subroutine atm_run(comp,
ImportState,ExportState, Clock, rc)
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Design PrinciplesTransforms and States
Gridded Components using Transforms do not have
to return control to a higher level component to
send or receive State data from another
component. They can receive function pointers
which are methods that can be called on the
states.
call ESMF_CompRun(atm, xform) call
ESMF_CompRun(ocn, xform)
coupler
transform
ocn_component call ESMF_StateXform(ex_state,
xform)
atm_component call ESMF_StateXform(xform,
im_state)
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Design PrinciplesRegistration Process
Components must provide a single externally
visible entry point which will register the other
entry points with the Framework. Components
can - Register one or more Initialization, Run,
Finalize, and Checkpoint entry points. - Register
a private data block which can contain all data
associated with this instantiation of the
Component particularly useful when running
ensembles.
Higher level Comp
ESMF Framework Services
cmp_final()
cmp_register()
cmp_run()
cmp_init()
Public subroutine Private subroutine
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ESMF User Environments

• Languages F90 (predominately), C
• Systems Unix/Linux variants (inc IBM, SGI,
  Compaq, Linux clusters, Mac OS X)
• Memory MPI, PThreads/SMP
• Execution SPMD, MPMD
• Runtime system LoadLeveler, poe, bsub,
  mpirun

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Component Details

• Components create others
• Nested parent/child relationship
• Annotated States contain all data passed between
  components
• Data objects use CF name conventions
• Can be created dynamically
• Initialization/Run/Finalize/Checkpoint