NCAR/MMM Support for WRF and MPAS
The Mesoscale and Microscale Meteorology (MMM) Laboratory at the National Center for Atmospheric Research (NCAR) has led the development and support of WRF-ARW to the community since its inception in the late 1990s. The WRF-ARW modeling system is mature, and it is the most popular and widely-used atmospheric modeling system in the world. For the five full years through 2022, the average number of annual WRF registrations exceeded almost 4,000/yr and publications exceeded 1100/yr, with the totals for 2022 being 3,444 registrations and 1182 publications, the highest single-year numbers in WRF’s history. There are at least eight developed and tuned variants of the WRF system (e.g., WRF-Chem, WRF-Hydro, etc.), and no other atmospheric model offers such a range of research and forecasting specializations to meet the community’s broad spectrum of needs. Given the extensive use of WRF in the U.S. and international atmospheric modeling communities, we are not planning to retire WRF or step away from its support and maintenance in the foreseeable future. Furthermore, we believe that it is primarily the modeling community that should drive these decisions through feedback to us and NSF, and through their continued use (or not) of the modeling system.
Over the past decade NCAR/MMM has also been developing the Model for Prediction Across Scales (MPAS) - Atmosphere, and supporting its use in the community. MPAS was developed to augment WRF by providing a more effective modeling system for global applications. MPAS now has a well-tested regional capability, but it currently includes only a small fraction of the capabilities available in WRF. MPAS will take on more WRF capabilities as it evolves, but most of these capabilities will be brought in through community-based efforts. In addition to maintaining a standalone version of MPAS for weather applications, MPAS is being incorporated into CESM/CAM as part of the System for Integrated Modeling of the Atmosphere (SIMA) development effort. MPAS will provide full earth-system modeling capabilities, including convection-permitting simulation capabilities, to the weather and climate modeling communities through this effort. These capabilities are critical if the weather and climate communities making use of NCAR models are to remain at the forefront of simulation-based atmospheric and earth-system science.
Recognizing the need to evolve our modeling tools as represented in our MPAS and SIMA efforts, and also appreciating the widespread use of WRF and its utility in the modeling community, MMM development resources are focusing more on MPAS, and support efforts for both models are being streamlined. Towards this end we have:
- Moved the WRF code to an open repository on github and moved WRF development and its release to this repository (consistent with the code management for MPAS).
- Established procedures for community developers to contribute code directly through git pull requests to the open source repository.
- Established a combined online help forum for both WRF and MPAS to allow users to benefit from previously addressed problems and questions and to increasingly utilize community expertise in providing advice to other users.
- Adapted a suite of model physics to conform to the accepted CCPP interface standard to permit WRF and MPAS to utilize the same physics from a common physics repository.
The WRF-MPAS team within MMM is a small group with limited resources, and consequently supporting WRF-MPAS as community modeling systems will also require active participation of the research community. With this in mind, we continue working with the research community to:
- Encourage users seeking assistance through the online help forum to conscientiously search for related issues that have been previously posted before submitting a new help request.
- Promote active participation of experienced WRF and MPAS model users in the community in addressing help requests posted to the online forum.
- Clarify requirements and procedural guidelines for community code contributors, emphasizing their lead responsibilities in adapting their contributions for community release.
- Enforce participation of community code contributors in addressing issues raised by users relevant to their contributed codes (part of current expectations for code contributors).
- Restrict physics consulting support to an identified subset of all available physics packages (consistent with an emphasis on supported physics suites).
- Encourage new development efforts led and funded by groups and agencies outside MMM. (The MMM WRF-MPAS team would likely need external support to participate significantly in these development efforts).
- Evolve toward an open-development software engineering (and scientific engineering) paradigm. Defining what this would entail and how it could work successfully will require substantial further discussions among the MMM development team and community users.
Updated: 28 November 2023