{
  "abstract": "The integration of stiff atmospheric chemical systems is a major computational cost in Earth System Models and poses challenges for numerical stability as chemical complexity and temporal resolution increase. In this study, we implement a semi-implicit two-stage Rosenbrock method (ROS2) in the Energy Exascale Earth System Model version 1 (E3SMv1) and evaluate it as an alternative chemistry time-integration scheme. ROS2 is tested with two interactive chemical mechanisms of substantially different size: chemUCI (60 prognostic species) and trop_strat_mozart_mam4 (155 prognostic species). Numerical experiments include short simulations to quantify computational cost, a box-model timestep-refinement analysis, and one-year integrations to examine numerical stability and solution sensitivity. At the same 180 s chemistry timestep, ROS2 requires approximately 33 % less chemistry integration time than the original iterative implicit solver on the tested Cori/KNL CPU platform. The magnitude of this speedup is configuration dependent. Global-mean surface-ozone differences among the tested configurations are small (≤ 1.03 ppb), and the one-year integrations show no evidence of numerical instability. Spatial and diurnal differences in ozone, NO, NO ₂ , and OH are species- and mechanism-dependent, indicating sensitivity to both timestep and solver formulation rather than a common systematic bias. These results support ROS2 as a lower-cost alternative to the current implicit integrator when E3SM chemistry is operated at short timesteps; additional timestep-refinement tests and benchmarking on contemporary CPU/GPU systems are needed to quantify coupled-model convergence and performance portability.",
  "abstract_shown": true,
  "affiliations": [
    "University of Tennessee at Knoxville (Knoxville, United States of America)"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Rong-You Chien"
    },
    {
      "affs": [
        0
      ],
      "name": "Joshua S. Fu",
      "orcid": "0000-0001-5464-9225"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/at2ha7qh155pd.bib",
  "cited_by": 0,
  "doi": "10.5194/gmd-19-10309-2026",
  "fulltext_url": null,
  "id": "at2ha7qh155pd",
  "issns": [
    "1991-9603"
  ],
  "landing_url": "https://gmd.copernicus.org/articles/19/10309/2026/",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [],
  "openalex": null,
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-29",
  "publisher": "Copernicus GmbH",
  "ris": "https://research.draconitic.com/paper/at2ha7qh155pd.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:20:49Z",
      "native_id": "10.5194/gmd-19-10309-2026",
      "source": "crossref",
      "url": "https://gmd.copernicus.org/articles/19/10309/2026/"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "issn:1991-9603",
      "subfield": "general"
    }
  ],
  "title": "Using a two-stage Rosenbrock solver to increase computational efficiency in the DOE's Exascale Earth System Model version 1 (E3SMv1)",
  "title_text": "Using a two-stage Rosenbrock solver to increase computational efficiency in the DOE's Exascale Earth System Model version 1 (E3SMv1)",
  "type": "peer-reviewed",
  "updated_at": "2026-10-31T00:21:14Z",
  "url": "https://research.draconitic.com/paper/at2ha7qh155pd",
  "venue": "Geoscientific Model Development",
  "versions": [
    {
      "doi": "10.5194/egusphere-2026-1451",
      "pid": null,
      "relation": "preprint",
      "title": null,
      "venue": null
    }
  ]
}