Evolving the UFS to Meet our Future Prediction Needs: A Case Study from CAM.

The Unified Forecast System (UFS) embodies a vision for a comprehensive Earth modeling system that is underpinned by a vibrant community of operational model developers, research laboratory scientists, university students and faculty, and the wider community. Under this philosophy, collaboration is made more effective and straightforward under the assumption that the UFS has the critical major components required for the community. This may be infrastructure or the underlying scientific software, such as the atmospheric or oceanic dynamical cores. What options exist for the community to improve the UFS at its major component level, especially in the case where a new major Earth system model subcomponent is needed?

Recent studies have shown that the current atmospheric dynamical core used in the UFS, while successfully implemented for global resolution by the NWS, has several deficiencies for convective-scale prediction that appear to be unmitigatable despite the best efforts by a number of developers over the past several years. Given these challenges, it is natural to consider adding a new dynamical core more suitable for convective-scale prediction. What are the steps and requirements to bring a new dynamical core into the UFS? Can multiple dynamic cores coexist? We argue that the UFS need not be restricted to a single atmospheric dynamical core in order to better meet the current and growing needs of the operational and research community.

This is a new question for the UFS community and its developers, and it has previously not been discussed in detail. This talk will attempt to lay out the needed steps toward adding another atmospheric dynamical core to the UFS. Additionally, if another dynamical core needs to be added to the UFS system, this would provide an excellent opportunity to engage and involve a wider group of developers (academic, students, private sector) into this process in a more holistic manner.