CV

Education

• B.S. in Geophysical Sciences, University of Chicago, 2018
• PhD in Atmospheric, Oceanic, and Planetary Physics, University of Oxford, 2022 (expected)

Research experience

• DPhil Student - University of Oxford - Department of Physics, Sept. 2018 - present
  • Supervised by Raymond Pierrehumbert
  • I have carried out research on a variety of topics, generally aimed at understanding the conditions that allow for a temperate surface climate to be maintained on Earth-like planets.
  • I have multiple ongoing projects involving silicate weathering and its action as a stabilizing feedback on planetary climate.
  • I am also working on a collaborative project to model the properties of atmospheres with multiple condensable components of arbitrary concentration under varying assumptions about the retention of condensate in the atmosphere.
  • I am running models to examine the impacts of surface CO2 condensation on planetary climate.
  • I am preparing a manuscript describing the reduced sensitivity of planets in the mid-to-outer reaches of the habitable zone to transient CO2 perturbations of sizes that have caused catastrophe multiple times in Earth history.
• College Research Fellow - University of Chicago - Department of Geophysical Sciences, Sept. 2016 - 2018
  • Worked with Professors Dorian Abbot and Tiffany Shaw
  • We analyzed the circulation of the stratosphere during Snowball Earth scenarios and how it differs from the circulation under modern conditions by running the ECHAM6 global climate model with varying combinations of initial conditions
  • We derived a simple theoretical result that partially validates assumptions made in estimating the pCO2 during a Snowball event from geochemical proxies.
  • We derived an extension of the Statistical Transformed Eulerian Mean framework for analyzing atmospheric circulations.
  • Our simulations indicate that wave forcing on the stratosphere from the troposphere is considerably reduced in the Snowball state, the polar vortex is greatly strengthened, and the stratosphere is cold enough for the formation of a class of clouds that may have important impacts on the climate
• Student Research Technician - UChicago - Department of Geophysical Sciences, June 2016 - 2018
  • Worked with professor Fred Ciesla
  • Modeled the thermal evolution of chondritic planetesimals in the early Solar System to understand how various parameters affect the final porosity state of a body (with implications for the expected outcomes of impacts between bodies)
  • Wrote a realistic numerical model of planetesimal evolution through time that considers abundances of radioactive elements, porosity evolution, hot-pressing, and heat transport within the body
• Collaborative Research Project - UChicago - Dept. Of Geophysical Sciences, June 2017 - Nov. 2017
  • Worked as part of Dorian Abbot’s research group Science Family
  • We ran the intermediate complexity global climate model PLaSIM to investigate the effect of solar day length on the transition to and from a Snowball state
  • We discovered that the strength of hysteresis between Snowball and non-Snowball decreases as a planet’s rotation approaches a tidally locked state, at which point the hysteresis disappears.
  • This result suggests that sudden transitions to global glaciation may be less frequent and less severe on tidally influenced planets, bolstering their habitability compared to rapid rotators.

Publications

Decrease in hysteresis of planetary climate for planets with long solar days

Abbot, Dorian S., Jonah Bloch-Johnson, Jade Checlair, Navah X. Farahat, R. J. Graham, David Plotkin, Predrag Popovic, and and Francisco Spaulding-Astudillo. "Decrease in Hysteresis of Planetary Climate for Planets with Long Solar Days" The Astrophysical Journal 854, no. 1 (2018): 3. DOI:10.3847/1538-4357/aaa70f.

The snowball stratosphere

Graham, R. J., T. A. Shaw and D. S. Abbot, 2019: "The snowball stratosphere", Journal of Geophysical Research: Atmospheres, 10.1029/2019JD031361.

Thermodynamic and Energetic Limits on Continental Silicate Weathering Strongly Impact the Climate and Habitability of Wet, Rocky Worlds

Graham, R. J., R. T. Pierrehumbert, 2020: "Thermodynamic and Energetic Limits on Continental Silicate Weathering Strongly Impact the Climate and Habitability of Wet, Rocky Worlds", Astrophysical Journal, 10.3847/1538-4357/ab9362.

Hydrological cycle changes explain weak Snowball Earth storm track despite increased surface baroclinicity

Shaw, Tiffany and R. J. Graham, 2020: "Hydrological cycle changes explain weak Snowball Earth storm track despite increased surface baroclinicity", Geophysical Research Letters, DOI:10.1029/2020GL089866.

High pCO2 Reduces Sensitivity to CO2 Perturbations on Temperate, Earth-Like Planets Throughout Most of Habitable Zone

Graham, Robert J., 2021: "High pCO2 Reduces Sensitivity to CO2 Perturbations on Temperate, Earth-Like Planets Throughout Most of Habitable Zone", Astrobiology, DOI:10.1089/ast.2020.2411.

A Multispecies Pseudoadiabat for Simulating Condensable-rich Exoplanet Atmospheres

Graham, R.J., Tim Lichtenberg, Ryan Boukrouche, and Raymond T. Pierrehumbert 2021: "A Multispecies Pseudoadiabat for Simulating Condensable-rich Exoplanet Atmospheres", Astrobiology, DOI:10.3847/PSJ/ac214c.

Talks

Modeled Cross-Tropopause Mass Exchange Comparable in Modern and Snowball Earth

May 10, 2018

Talk at Ice, oceans and atmosphereson Earth and elsewhere, National Research Council (CNR), Rome, Italy

Pressure-dependence of silicate weathering feedback may be weaker than usually assumed in studies of rocky planet climate

December 13, 2019

Talk at American Geophysical Union Fall Meeting 2019, San Francisco CA, USA

Hydrologic Control of Silicate Weathering and Rocky Planet Climate Stability

January 08, 2020

Talk at Rocky Worlds: from the Solar System to Exoplanets, Kavli Institute, University of Cambridge, UK

Energetic and Thermodynamic Limits on Continental Silicate Weathering Strongly Impact the Habitability of Wet, Rocky Worlds

January 13, 2020

Talk at British Planetary Sciences Conference 2020, University of Oxford, UK

Outreach

• John Michael Godier’s Event Horizon podcast, Sep. 14th 2020
  • Interviewed to discuss the implications of the discovery of phosphine in Venus’s atmosphere
  • As of Sep. 25th 2020, interview has 174,256 views
  • https://youtu.be/7YNxMVJN-Hk
• Jesus College Research Symposium, Jun. 6th 2019
  • Gave a public talk about my research
• Pint of Science, May 22nd 2019
  • Gave a public lecture at a pub about my research
  • Received free beer