Tsigaridis et al. (2025) ROCKE-3D 2.0: an updated general circulation model for simulating the climates of rocky planets

Identification

• Journal: Geoscientific model development
• Year: 2025
• Date: 2025-09-09
• Authors: Kostas Tsigaridis, Andrew S. Ackerman, Igor Aleinov, Mark A. Chandler, Thomas L. Clune, Christopher M. Colose, Anthony D. Del Genio, Maxwell Kelley, Nancy Y. Kiang, Anthony Leboissetier, J. P. Perlwitz, Reto Rüedy, Gary L. Russell, Linda E. Sohl, M. J. Way, Eric Wolf
• DOI: 10.5194/gmd-18-5825-2025

Research Groups

• NASA Goddard Institute for Space Studies (GISS)
• Columbia University (Center for Climate Systems Research, Department of Applied Physics and Applied Mathematics)
• Sellers Exoplanet Environments Collaboration (NASA Goddard Space Flight Center)
• NASA Goddard Space Flight Center
• Uppsala University (Department of Physics and Astronomy, Theoretical Astrophysics)
• NASA NExSS Virtual Planetary Laboratory
• University of Colorado Boulder (Laboratory for Atmospheric and Space Physics)

Short Summary

This paper presents ROCKE-3D version 2.0, an updated generalized three-dimensional general circulation model (GCM) designed for simulating the climates of rocky planets in both the Solar System and exoplanetary contexts. It details new physics, expanded configurations, and quantifies how different component choices affect model results, demonstrating its enhanced capabilities for diverse planetary conditions.

Objective

• To present the second generation of ROCKE-3D, a generalized three-dimensional general circulation model (GCM), describing its updated physics and expanded capabilities for simulating the climates of rocky planets.
• To quantify how different model component choices (radiation schemes, atmospheric compositions, ocean configurations, and resolutions) affect simulated climate results.
• To provide a publicly available, well-documented, and supported tool for the scientific community to explore a wide range of planetary and ancient Earth climates.

Study Configuration

• Spatial Scale:
  • Atmosphere: Medium resolution (4° × 5° latitude by longitude) or Fine resolution (2° × 2.5° latitude by longitude), both with 40 vertical layers up to 0.1 hPa.
  • Ocean: Medium resolution (4° × 5° latitude by longitude) with 13 vertical layers, or Fine resolution (1° × 1.25° latitude by longitude) with 40 vertical layers.
• Temporal Scale:
  • Spinup: Typically 10 simulation years for atmospheric radiative balance.
  • Analysis: 20 simulation years for initial evaluation; 100 years for long-term climatological analysis.
  • Equilibration: 200 to 500 years for prescribed (p) and Q-flux (q) ocean configurations; 1000 to 2000 years for dynamic (o) ocean configurations; up to 6000 years for full deep ocean equilibrium.

Methodology and Data

• Models used:
  • ROCKE-3D 2.0 (Resolving Orbital and Climate Keys of Earth and Extraterrestrial Environments with Dynamics), a descendant of GISS ModelE2.1.
  • GISS radiation scheme (optimized for modern Earth-like atmospheres).
  • SOCRATES radiation scheme (generalized for diverse atmospheres and stellar energy distributions).
  • Ent Terrestrial Biosphere Model (Ent TBM) for vegetation.
  • Hydrostatic dynamical core (Arakawa B grid, conservative quadratic upstream scheme for scalars, leapfrog scheme for momentum/air mass).
  • Sea ice model (two mass layers, two thermal layers, brine pocket formulation).
  • Generalized land surface hydrology for arbitrary topography (dynamic lakes, river transport).
• Data sources:
  • HITRAN 2012 and MT-CKD water vapor continuum model for SOCRATES spectral files.
  • BT-Settl and BT-NextGen grids of models for stellar spectra.
  • SPARC/SOLARIS (Lean et al., 2005) for solar spectrum.
  • MUSCLES Database (Loyd et al., 2016) for stellar spectra.
  • PARSEC for Sun red giant phase stellar spectra.
  • International Satellite Cloud Climatology Project (ISCCP) D1 cloud climatology for Earth-centric cloud inhomogeneity.
  • Levitus et al. (1994) and Levitus and Boyer (1994) for modern Earth ocean initial conditions.
  • Davies (2013) for modern Earth geothermal heat flux maps.
  • Paleogeographic reconstructions for ancient Earth boundary conditions (Sturtian, Late Ordovician, Early Jurassic, Mid-Cretaceous, Cretaceous–Paleogene boundary, mid-Pliocene).
  • Modern Venusian topography for ancient Venus studies.
  • Modern Mars topography for ancient Mars studies.
  • Modern lunar topography for early Moon atmosphere studies.

Main Results

• ROCKE-3D 2.0 incorporates significant updates including generalized land surface hydrology, optional geothermal heat flux, capabilities for thin atmospheres (down to 10 µbar), and an improved calendar system with equation of time effects.
• The model supports 36 template configurations, combining two radiation schemes (GISS, SOCRATES), three atmospheric compositions (preindustrial Earth, aerosol/ozone-free, anoxic), three ocean configurations (prescribed, Q-flux=0, dynamic), and two resolutions (medium, fine).
• SOCRATES radiation is more computationally expensive but offers greater flexibility for non-Earth-like atmospheres, while GISS radiation is faster but limited to Earth-like conditions.
• Q-flux=0 ocean configurations consistently result in significantly colder global mean surface temperatures and more extensive polar ice caps (up to 32° further from poles compared to dynamic ocean) due to the absence of oceanic heat transport.
• Atmospheres without stratospheric ozone (aerosol/ozone-free and anoxic) exhibit no stratospheric temperature inversion, leading to colder stratospheric temperatures and 2-3 orders of magnitude lower stratospheric water vapor concentrations compared to preindustrial Earth.
• Fine resolution (2° × 2.5° atmosphere, 1° × 1.25° ocean) significantly increases computational cost (up to an order of magnitude with a dynamic ocean) but improves the resolution of coastlines and narrow straits.
• Aquaplanet simulations, especially with Q-flux=0 oceans, are highly susceptible to snowball instabilities, with small CO2 perturbations leading to large climate bifurcations.
• ROCKE-3D 2.0 maintains consistency with its parent GISS ModelE2.1 for Earth-centric simulations, while providing expanded capabilities for diverse planetary environments.

Contributions

• Presents a comprehensive description and evaluation of ROCKE-3D 2.0, a significantly updated and generalized GCM for rocky planet climate simulations.
• Systematically quantifies the impact of various model components and parameterizations (radiation schemes, atmospheric compositions, ocean dynamics, spatial resolutions) on simulated planetary climates, providing crucial guidance for exoplanet and paleoclimate studies.
• Introduces new physics, including generalized land surface hydrology, geothermal heat flux, and thin atmosphere capabilities, expanding the model's applicability to a broader range of planetary conditions.
• Offers a wide array of pre-configured planetary and ancient Earth boundary conditions, facilitating diverse research applications.
• Enhances community access and usability by making the model code, configurations, and simulation data publicly available, complemented by extensive online documentation and tutorial sessions.
• Contributes to the development of more robust Earth system models by generalizing assumptions and pushing capabilities through exoplanet and Earth-through-time research.

Funding

• NASA’s Nexus for Exoplanet System Science (NExSS)
• NASA Interdisciplinary Consortia for Astrobiology Research (ICAR)
• NASA Earth and Planetary Science Division Research Programs (ISFM work package ROCKE-3D at the Goddard Institute for Space Studies)
• GSFC Sellers Exoplanet Environments Collaboration (SEEC)
• NASA Modeling, Analysis and Prediction program (MAP)
• NASA Solar System Workings program (award 80NSSC21K0163)
• NASA High-End Computing (HEC) Program through the NASA Center for Climate Simulation (NCCS) at Goddard Space Flight Center

Citation

@article{Tsigaridis2025ROCKE3D,
  author = {Tsigaridis, Kostas and Ackerman, Andrew S. and Aleinov, Igor and Chandler, Mark A. and Clune, Thomas L. and Colose, Christopher M. and Genio, Anthony D. Del and Kelley, Maxwell and Kiang, Nancy Y. and Leboissetier, Anthony and Perlwitz, J. P. and Rüedy, Reto and Russell, Gary L. and Sohl, Linda E. and Way, M. J. and Wolf, Eric},
  title = {ROCKE-3D 2.0: an updated general circulation model for simulating the climates of rocky planets},
  journal = {Geoscientific model development},
  year = {2025},
  doi = {10.5194/gmd-18-5825-2025},
  url = {https://doi.org/10.5194/gmd-18-5825-2025}
}