03/18/2024
By Lynne Schaufenbil
Abstract: For many years, people have thought about the features of worlds beyond Earth that could support a habitable environment (mostly) for life as we know it. The first exoplanet discoveries finally provided the rationale for taking a more serious approach to habitability studies through the quantitative characterizations that climate models could offer. Given the minimal data available these new-found exoplanets and the modern-Earth-centric complexity of most 3D global climate models (GCMs), the exoplanet community first took advantage of the efficiency and flexibility of 1-D models to make these the primary tools for climate characterization studies. As the field has matured and evolved, climate modeling of exoplanets has expanded to include more options, from increasingly sophisticated 1D models incorporating photochemistry to 3D GCMs that have either shed their modern Earth limitations or been built from scratch without them. Without many constraints from data, though, these modeling tools have often been left to simply explore the possibilities -- and if two models got different results from running similar experiments, who could say which, if either, might be producing more reasonably accurate results?
Now that JWST has begun to return observations, the future of exoplanet climate modeling will need to look quite different -- and perhaps more like modern Earth climate modeling in practice. We can expect data-model comparisons for "ground truthing" experimental results, which will help us to refine the workings of the models themselves -- just as satellite observations and Earth paleoclimate studies are used to improve the performance of modern Earth GCMs. It now also becomes important to understand how the hierarchy of exoplanet climate models relate to each other as well as to data. Organized model intercomparisons engaging the exoplanet community as a whole will play a crucial role in this context, just as it does in practice within the modern Earth climate community through the Coupled Model Intercomparison Project (CMIP).
The CUISINES Working Group of NASA’s Nexus for Exoplanet Systems Science (NExSS) RCN has been created to support a systematized approach to evaluating the performance of exoplanet models, and provide a framework for conducting community-organized exoplanet Model Intercomparison Projects (exoMIPs). I will discuss some of the current exoMIPs that are under way or about to begin, and what we envision as the foundation for a growing exoplanet climate modeling community of practice.
Bio: Linda Sohl is an Earth and planetary systems scientist, with a background in sedimentary geology and paleoclimatology. Her research focuses on using NASA's global climate models to expand upon our knowledge of past habitable phases of Earth as inferred from the geologic record. She is especially interested in understanding the climate processes of extreme cold environments like Snowball Earth, identifying the impacts of those conditions on the evolution and distribution of more complex life, and figuring out what all that might mean for the existence of life on worlds on the outer edge of their star’s habitable zone. More broadly, she is also interested in identifying the potentially observable global climate characteristics of habitable exoplanets in other star systems.
If you are interested in attending, please contact Lynne_Schaufenbil@uml.edu for the Zoom link.