Initial Results from the Integration of Earth and Space Frameworks

1. Cecelia DeLuca/NCAR, Alan Sussman/University of Maryland, Gabor Toth/University of Michigan Abstract There is increasing call to couple Earth and space models, as the interplay between the regions is an active topic of basic research and a key factor in operational prediction systems. Two pilot projects to combine Earth and space software frameworks have produced initial technical results.  The projects, which were initiated under NASA and NSF funding, demonstrate 1) transfers of data between models using the Earth System Modeling Framework (ESMF) and those that are part of the Center for Integrated Space Weather Modeling (CISM) and 2) transfers of data between models using ESMF and those running under the Space Weather Modeling Framework (SWMF).  We describe technical approaches, capabilities achieved, and possible next steps. Framework Comparison Table Pilot Projects Initial Results from the Integration of Earth and Space Frameworks 1. ESMF and CISM / InterComm Coupling Motivation The main motivations for interfacing ESMF-based Earth simulations to space simulations and vice versa are the desire to better express boundary conditions for these domains, and the desire to improve representation of the boundary region. End goals are to deepen understanding of physical processes and to produce better forecasts. The ability to exchange component versions between the CISM and SWMF frameworks would afford space weather researchers more opportunities for experimentation and collaboration. There are also a number of upper atmosphere researchers who are interested in implementing their component versions in an ESMF-compatible way. • Modifications Required • 3 new ESMF functions required • 1 to translate ESMF array descriptors into InterComm descriptors • ESMF_ArrayExternalICTranslate() • 2 to export/import ESMF sub-arrays to another program • ESMF_ArrayExternalICSend() • ESMF_ArrayExternalICRecv() • Status • Implementation of prototype complete and tested • Currently limited to block array distributions • InterComm functions will appear as option in ESMF release • Prototype coupling of ESMF model to NCAR space weather model is being discussed • Future Work • We will demonstrate in a simple model the ability to execute a data transformation between an ESMF component and a CISM component using InterComm, with the ESMF component using ESMF interfaces and the CISM component using native InterComm interfaces. ESMF App Driver ESMF Coupler ESMF Component 1 (e.g. land) ESMF Component 2 (e.g. atm) Multiple executables FRAMEWORK: Earth System Modeling Framework (ESMF) CISM Model Example: GEOS-5 AGCM • The ESMF architecture is based on components with standard interfaces and standard methods • An ESMF application runs as a single executable • New components can be added to the application systematically • Data in and out of components are state types that contain fields, bundles of fields, arrays, or nested states • Toolkits include regridding and redistribution methods and utilities such as time management • ESMF is free for download at http://www.esmf.ucar.edu InterComm data transfer and sequencing Configuration • InterComm is used for data transfers between an ESMF application and a CISM model (or other non-ESMF code) • These are in separate executables • Data transfers can be from anywhere, to anywhere • Minimal changes to codes • Each code doesn’t need to know anything about the internals of the other FRAMEWORK: Space Weather Modeling Framework (SWMF) Solar Corona Eruptive Event Generator Inner Heliosphere Solar Energetic Particles Photosphere to Corona • The SWMF architecture is based on components with generic interfaces • A SWMF application runs as a single executable • Many different configurations may be run • The SWMF is freely available at http://csem.engin.umich.edu Coming Soon 2. ESMF and SWMF Coupling Similarities Between ESMF and SWMF ESMF and SWMF are layered and structured in a similar fashion (see diagrams below). This made it rather straightforward to modify the SWMF so that it could be run as an ESMF component. Problems that occurred during integration were due largely to the immaturity of aspects of the ESMF software at the time of the implementation. ESMF SWMF Radiation belts Global Magnetosphere SWMF ESMF App Driver ESMF Coupler Conclusions Coming Soon Inner Magnetosphere Coming Soon Plasmasphere ESMF Earth System Component ESMF SWMF Component Polar Wind Upper Atmosphere Ionosphere Electrodynamics The initial results from these pilot projects are proof of concept that SWMF components, CISM components, and ESMF components can be connected to each other to create applications. A natural next step is to explore the possibility of component exchanges between the CISM and SWMF frameworks, perhaps mediated by ESMF interfaces. SWMF Driver FRAMEWORK: Center for Integrated Space Weather Modeling (CISM) / InterComm Single Executable • In CISM applications, the InterComm library (University of Maryland) is used for parallel data transfers between models that are in separate executables • The Overture framework (LLNL) for solving PDEs in complex moving geometries is used to write coupling code, which may be put in its own separate executable or within a subroutine of one of the models being coupled • The approach requiress minimal modification to existing programs • InterComm and Overture are both general purpose, freely downloadable packages Configuration • The entire SWMF is wrapped as an ESMF component • The SWMF component can communicate data to one or more Earth system components • The application is run using an ESMF driver • The application runs as a single executable • Status • Implementation of prototype complete and tested • ESMF functions appear as options in the SWMF distribution