by Lynda Lester
An innovative modeling framework is helping smooth the way for simulations that run the gamut from weather and climate to emergency response and battlefield settings. Scientists and model developers from 15 U.S. universities joined colleagues from NCAR and various research labs around the world at the fourth Earth System Modeling Framework Community Meeting, held July 20-22 at the Massachusetts Institute of Technology (MIT).
The ESMF project is a national effort to build a software infrastructure that allows different weather, climate, and data assimilation components to operate together on a variety of platforms, from laptops to supercomputers. ESMF allows scientists to build models quickly, reuse existing software rather than reinvent it, and exchange modeling components in a systematic way.
Meeting attendees saw the results of ESMF in action, as speakers described taking steps to bring ESMF into production applications at NOAA's National Centers for Environmental Prediction and Geophysical Fluid Dynamics Laboratory; NCAR; the University of California, Los Angeles; NASA Goddard Space Flight Center; the Naval Research Laboratory; MIT; and other sites. The meeting also showcased four field tests in which models from these centers and others were combined into new Earth system simulations.
Erik Kluzek, an NCAR software engineer who presented at the meeting, explains the appeal of the new modeling framework. "ESMF is all about taking the burden of designing software off the scientists and shifting it to software engineers, so scientists can concentrate on science," says Kluzek. "For example, I work with the Community Climate System Model. In CCSM, we want to be able to ‘plug and play' different models into our system, to be able to easily switch in various land and atmosphere models. ESMF provides a software interface that makes it natural to do that."
As proof of concept, Kluzek and colleagues used ESMF to connect the CCSM's atmosphere model (the Community Atmosphere Model or CAM) to two other systems for the first time: MIT's ocean model and the Spectral Statistical Interpolation analysis from NASA Goddard.
ESMF provides an interface specification so that groups working at different institutions and in different disciplines can generate software components that work together. It includes tools for regridding, data decomposition, and communication on parallel computers and for common modeling functions such as time management and message logging. The goal is twofold: to increase scientific productivity and to promote new scientific opportunities.
A multiagency collaboration
ESMF is being developed and deployed by a multiagency collaboration that includes many of the major geophysical modeling and data assimilation efforts in the United States. Support for ESMF development and application teams is provided by the NASA Earth Science Technology Office, the High-Performance Computing Modernization Program of the U.S. Department of Defense, and NSF. Staff from modeling centers at the U.S. Department of Energy, DOD, NASA, NOAA, NSF, and numerous universities have contributed requirements, feedback, and software to ESMF and are now beginning to evaluate and adopt the framework.
"ESMF is an unprecedented community effort," says Cecelia DeLuca, manager of the core implementation team, based in NCAR's Scientific Computing Division. The team is working with a change review board and a joint specification team, both with members from many other organizations, to implement ESMF on a day-to-day basis. "It's tremendously exciting to see. When we started, many of the groups we were working with had no regular contact with each other. ESMF has facilitated real cooperation that extends across agencies."
The more institutions that adopt ESMF, the more will scientists be able to reuse software rather than writing it from scratch, and the larger will be the pool of interoperable codes from which new applications can be composed.
"ESMF could become a central part of how climate models and data assimilation programs are structured, so there can be more reuse of codes than within a given shop," notes Arlindo da Silva (NASA Goddard), who heads the ESMF data assimilation applications team. "It will open doors on a technical level and make collaboration easier if people want to collaborate. It's a very needed addition to the kind of modeling we do."
Many applications and projects
The ESMF developers are working with the University of Michigan to bring grids used in space weather studies into ESMF. They are also working with Earth System Grid developers at NCAR to create an end-to-end knowledge environment that encompasses both modeling and data analysis services.
A new NASA initiative called the Modeling Analysis and Prediction Environment is aimed at integrating NASA's climate modeling and data assimilation efforts into the ESMF environment, while DOD's Battlespace Environment Institute is using ESMF as its standard for component coupling.
Smaller institutions also stand to benefit from ESMF, says DeLuca. "This kind of community, open-source software really opens up modeling to a lot of university groups who might have not been able to address the kind of problems they now can address by using the infrastructure we're building. We're helping to lower the bar to get involved with modeling for many researchers with limited resources."