Water Isotope Model Intercomparison Project (WisoMIP): Present-day Climate

Abstract

We present the first results of the Water Isotope Model Intercomparison Project (WisoMIP), with Phase 1 focused on modern simulations (1979–2023) from a suite of isotope-enabled atmospheric general circulation models nudged to ERA5 reanalyses. Water sources, mixing, and rainout history influence the isotopic composition of vapor and precipitation, making these simulations powerful tools for tracing the global water cycle. By prescribing identical winds, sea surface temperatures, and sea ice conditions, we isolate differences in water isotope behavior across models, controlling for variability in atmospheric dynamics and mean climate. Our analyses show that the ensemble mean best matches observations, as individual model errors cancel out to yield a more accurate representation of Earth’s isotope distributions. We also evaluate trends and responses to major climate modes during the recent warming period, highlighting regional and temporal sensitivities in the isotope signals. These diagnostics extend beyond traditional model evaluation metrics (e.g., temperature, precipitation) to reveal uncertainties in physical processes and guide improvements in model parameterizations. The resulting modern nudged ensemble dataset serves as a benchmark for isotope-enabled model development, satellite product comparison, and understanding of water cycle changes in a warming climate. Given its standardized design and broad participation, WisoMIP provides a valuable “isotope reanalysis’ product for applications ranging from paleoclimate reconstruction to model tuning. Our work demonstrates the importance of coordinated isotope model evaluation in advancing the use of water isotopes as a diagnostic tool in climate science.

Authors 24

1. Hayoung Bong corresponding

   Goddard Institute for Space Studies

   Affiliation as printed

   NASA Goddard Institute for Space Studies, New York, NY, USA

2. Allegra N. LeGrande

   Goddard Institute for Space Studies

   Affiliation as printed

   NASA Goddard Institute for Space Studies, New York, NY, USA

3. Sylvia Genevieve Dee

   Rice University

   Affiliation as printed

   Department of Earth, Environmental, and Planetary Sciences, Rice University, Houston, TX, USA

4. Jiang Zhu

   NSF National Center for Atmospheric Research · NSF NCAR Climate and Global Dynamics Laboratory

   Affiliation as printed

   Climate and Global Dynamics Laboratory, National Center for Atmospheric Research (NCAR), Boulder, CO, USA

   NCAR - National Center for Atmospheric Research [Boulder] (3090 Center Green Drive, Boulder, CO 80301 - United States)

5. Alexandre Cauquoin

   Rikkyo University · The University of Tokyo

   Affiliation as printed

   Institute of Industrial Science, The University of Tokyo, Kashiwa, Japan

   Rikkyo University [Tokyo] (Ikebukuro Campus 3-34-1 Nishi-Ikebukuro,Toshima-ku, Tokyo Japan 171-8501 - Japan)

6. Richard P. Fiorella

   Los Alamos National Laboratory

   Affiliation as printed

   Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA

7. Qinghua Ding

   University of California, Santa Barbara

   Affiliation as printed

   Department of Geography, University of California, Santa Barbara, CA, USA

   UC Santa Barbara - University of California [Santa Barbara] (Santa Barbara, CA 93106 - United States)

8. Niels Dutrievoz

   Centre National de la Recherche Scientifique · Université de Versailles Saint-Quentin-en-Yvelines · Commissariat à l'Énergie Atomique et aux Énergies Alternatives · Laboratoire des Sciences du Climat et de l'Environnement

   Affiliation as printed

   Laboratoire des Sciences du Climat et de l’Environnement (LSCE), IPSL, CEA–CNRS–UVSQ, Gif-sur-Yvette, France

9. Mampi Sarkar

   Rice University

   Affiliation as printed

   Department of Earth, Environmental, and Planetary Sciences, Rice University, Houston, TX, USA

10. Cécile Agosta

    Centre National de la Recherche Scientifique · Université de Versailles Saint-Quentin-en-Yvelines · Commissariat à l'Énergie Atomique et aux Énergies Alternatives · CEA Paris-Saclay - Etablissement de Saclay · Laboratoire des Sciences du Climat et de l'Environnement · CEA Paris-Saclay

    Affiliation as printed

    Laboratoire des Sciences du Climat et de l’Environnement (LSCE), IPSL, CEA–CNRS–UVSQ, Gif-sur-Yvette, France

    GLACCIOS - Glaces et Continents, Climats et Isotopes Stables (LSCE. CEA Paris-Saclay. Orme des merisiers. 91190 Saint-Aubin. - France)

11. Kei Yoshimura

    Rikkyo University · The University of Tokyo

    Affiliation as printed

    Institute of Industrial Science, The University of Tokyo, Kashiwa, Japan

    Rikkyo University [Tokyo] (Ikebukuro Campus 3-34-1 Nishi-Ikebukuro,Toshima-ku, Tokyo Japan 171-8501 - Japan)

12. Martin Werner

    Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung

    Affiliation as printed

    Alfred Wegener Institute (AWI), Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany

13. Atsushi Okazaki

    Chiba University

    Affiliation as printed

    Institute for Advanced Academic Research / Center for Environmental Remote Sensing (CEReS), Chiba University, Chiba, Japan

14. Camille Risi

    Centre National de la Recherche Scientifique · École Polytechnique · École Normale Supérieure - PSL · Sorbonne Université · Laboratoire de Météorologie Dynamique · Institut Polytechnique de Paris

    Affiliation as printed

    Laboratoire de Météorologie Dynamique (LMD) – IPSL, Sorbonne Université / CNRS / École Normale Supérieure – PSL / École Polytechnique – Institut Polytechnique de Paris, Paris, France

15. Hans Christian Steen‐Larsen

    Bjerknes Centre for Climate Research · University of Bergen

    Affiliation as printed

    Geophysical Institute, University of Bergen, and Bjerknes Centre for Climate Research, Bergen, Norway

16. Mathieu Casado

    Laboratoire des Sciences du Climat et de l'Environnement

    Affiliation as printed

    Laboratoire des Sciences du Climat et de l'Environnement

17. Sonja Wahl

    Bjerknes Centre for Climate Research · University of Bergen

    Affiliation as printed

    Geophysical Institute, University of Bergen, and Bjerknes Centre for Climate Research, Bergen, Norway

18. Jesse Nusbaumer

    NSF National Center for Atmospheric Research · NSF NCAR Climate and Global Dynamics Laboratory

    Affiliation as printed

    Climate and Global Dynamics Laboratory, National Center for Atmospheric Research (NCAR), Boulder, CO, USA

    NCAR - National Center for Atmospheric Research [Boulder] (3090 Center Green Drive, Boulder, CO 80301 - United States)

19. John R. Worden

    Jet Propulsion Laboratory

    Affiliation as printed

    Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA

20. Stephen Paul Good

    Oregon State University

    Affiliation as printed

    Department of Biological & Ecological Engineering, Oregon State University, Corvallis, OR, USA

21. Adriana Bailey

    University of Michigan

    Affiliation as printed

    Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA

22. Matthias F. Schneider

    Karlsruhe Institute of Technology

    Affiliation as printed

    Institute of Meteorology and Climate Research (IMK-ASF), Karlsruhe Institute of Technology, Karlsruhe, Germany

23. K. W. Bowman

    Jet Propulsion Laboratory

    Affiliation as printed

    Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA

24. Gavin A. Schmidt

    Goddard Institute for Space Studies

    Affiliation as printed

    NASA Goddard Institute for Space Studies, New York, NY, USA