The water isotope and water tracking capabilities are coming back to CESM, supported by a collaborative grant from the NSF Cyberinfrastructure for Sustained Scientific Innovation (CSSI) program. The SCI-SWIM project (Sustainable Community Infrastructure for Stable Water Isotope Modeling Enabling Earth System Research) will deliver a modernized, next-generation isotope-enabled CESM version 3 (iCESM3) to the scientific community.

SCI-SWIM runs from September 1, 2025 to August 31, 2030. We plan to complete the coupled model in the first two years. We will validate the model through three scientific use cases:

  • Shallow convection and cloud feedbacks: Advancing understanding of how convection influences cloud processes and climate sensitivity.
  • Arid and semi-arid hydroclimate: Investigating hydroclimate processes to disentangle land-surface effects from atmospheric transport.
  • Polar ice-core interpretation and ice-sheet processes: Exploring post-depositional atmosphere–snow–ice interactions and ice-sheet dynamics to enhance the interpretation of critical ice-core records and leverage isotope data to constrain ice-sheet behavior.

SCI-SWIM is co-led by Sylvia Dee (Rice University), Jiang Zhu, Peter Lauritzen and William Wieder at NSF NCAR. Software implementation efforts are spearheaded by NSF NCAR's William Sacks, Jesse Nusbaumer, and additional collaborators.

Diagram of the water cycle and isotopes
Figure: Conceptual diagram of the water cycle and its isotopes. iCESM will enable the community to leverage rich observational isotope datasets to better constrain CESM and gain process-level insights into the water cycle.