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GFDL Milestones 3rd Quarter, FY01
Evaluate the progress of new laboratory-wide Flexible Modeling
System and its evolving utility as the platform for launching all of GFDL's
weather / climate simulation experiments
(J. Anderson)
Purpose
GFDL has been engaged in a long-term effort to consolidate its modeling efforts in order to maximize scientific productivity, provide tools to facilitate research, and reduce the amount of redundant effort devoted to model development and maintenance at GFDL. This effort, referred to as the Flexible Modeling System ( FMS ), has reached the ambitious target of providing a common software infrastructure, or framework, with which all global models used at GFDL are developed. A particular catalyst for the effort was the need to have models that would run efficiently on a variety of new supercomputing platforms without requiring intolerable levels of work from GFDL's limited cadre of model developers.
Efforts
The Flexible Modeling System has been fully operational since late in 2000 and all GFDL global modeling groups have completed a transition to using FMS models for their routine research and analysis work. The low level memory management and I/O infrastructure of FMS was the key to a highly successful transition to GFDL's new scalable supercomputer in March, 2001. While many other modeling organizations have struggled to get models to run on computers of this type, GFDL's FMS-based models were operational upon delivery of the new computer. An independent effort to create powerful new web-based model diagnostic tools has progressed in concert with the FMS development giving model developers and users at GFDL an unprecedented capability to investigate science with models. The FMS framework has allowed greatly enhanced scientific interaction between different groups at GFDL and has catalyzed the development of next generation FMS-based global coupled models by GFDL's coupled model development team.
FMS is a software framework that provides both a set of standards for software development and a set of software that is compliant with these standards, along with comprehensive documentation.
Standards have been developed for many important parts of the modeling framework including:
- A column physics coding standard, used successfully for more than 4 years,
- Standards for restarting and controlling model integrations,
- A web-based documentation standard.
- A version control system and web-based user support allowing scientific users to develop new model versions while maintaining a variety of operational models for routine use.
A set of standard software support tools for atmospheric and oceanic modeling has been developed including:
- Memory management, communication and IO routines for supporting gridded, spectral and other data on a wide array of computer architectures,
- A flexible coupling tool that connects component atmosphere, ocean, ice, land, and other models,
- A tool for obtaining diagnostic output fields which empowers model users to examine the model with unprecedented ease,
- Compilation tools, time and calendar support tools, etc.
A vast array of models and modeling tools has been developed including but not limited to:
- A complete set of atmospheric column physics including all parameterizations that were in common use at GFDL plus a number of improved parameterizations that have been developed directly in the FMS framework,
- Modules for computing fluxes that are passed between coupled models,
- A B-grid atmospheric dynamical core with a variety of vertical coordinate options,
- A spectral atmospheric dynamical core,
- A land surface model,
- A sea ice model,
- FMS compliant versions of GFDL's Modular Ocean Model,
- A biosphere model being developed in the FMS framework by Princeton University,
- A suite of coupled climate and prediction models combining the FMS component models with the FMS coupling tool.
Customers
Initially, customers receiving direct benefits from FMS were model developers and model users within GFDL. With all global modeling groups within the lab now using FMS models, these internal customers have received a product that has significantly enhanced scientific progress at GFDL and promises to deliver even more benefits as GFDL works to develop next generation global coupled models based on FMS software.
Although original plans did not include external customers for FMS, the power of the software tools and models being developed has led to an increasing demand by outside groups for FMS products. In particular, versions of the GFDL Modular Ocean Model that use the FMS software tools have been delivered to NCEP, IRI, NCAR, COLA and other members of the IRI ARCs network. The FMS coupling software has been delivered to IRI and NCEP seasonal prediction groups. NASA has expressed interest in receiving the entire FMS system as a potential prototype for a coordinated modeling framework proposal ( NASA CAN ) that has recently been funded.
Significance
Within GFDL, FMS has changed the way in which modeling is approached. FMS provides models that are easier to develop, modify and use. By consolidating infrastructure throughout the lab, FMS has made it possible for all GFDL groups to make a relatively smooth transition to the new supercomputing platform. There is also a greatly enhanced level of communication and cooperation between groups thus catalyzing an increased level of scientific progress.
To date, FMS represents the only successful effort in the United States to establish a software framework and consolidate previously independent atmospheric and oceanic modeling groups as users of the framework. Given the increasing demand for US modeling groups to develop infrastructure that allows for greater interoperability, the FMS framework and GFDL's experience in developing it are of great interest to other major modeling groups. GFDL has been an active participant in efforts to coordinate US modeling efforts including the Climate Modeling Infrastructure Working Group and the NASA CAN. FMS serves as an example around which a unifying software framework could be built.
Success
The FMS development process is now mature and can be described as fully successful. Major modeling groups throughout GFDL have switched to FMS models for their routine research. FMS models run on new scalable platforms and eased GFDL's transition to its new computer platform. The shared infrastructure represented by FMS has greatly increased scientific communication between GFDL groups and has also significantly decreased redundant model development and analysis efforts.
Next Steps
The development of FMS is a continuing activity. Significant efforts are still needed to improve documentation, and most importantly, to enhance model efficiency on various platforms. There is also continued hope that FMS can serve as a springboard for GFDL participation in broader efforts to develop a common infrastructure for many US modeling groups. GFDL plans to begin a staged public release of FMS components beginning in late 2001 with the entire system along with complete models built on FMS software to be available via the web by mid-2002. Concurrent attempts to build a community of external users that can benefit from FMS and also feedback to accelerate model development at GFDL are planned.