February 2020 Meeting

Monday, February 10, 2020
6:00 - 7:30 pm

Pellissippi State Technical Community College
10915 Hardin Valley Road, Knoxville
J.L Goins Administration Building
Faculty/Staff Dining Room



Building process understanding through models: Exploring the interactions of hydrology, geomorphology, and soil science in warming Arctic tundra

Ethan Coon
Research Scientist
Oak Ridge National Laboratory

Oak Ridge, Tennessee


There are over 1500 gigatonnes of carbon stored in frozen ground throughout the Arctic, and warming climate is thawing this ground, offering the potential for decomposition and carbon release to the atmosphere.  Understanding the fate of this carbon is made difficult by a complex set of processes; thermal hydrology, geomorphology, and subsurface soil science all come together to determine even basic questions such as, "Will the Arctic become wetter or drier in future climates?" and "What will be the rates and chemical forms of the permafrost carbon feedback?"

Mechanistic models are a key tool for understanding the interactions of these processes.  Only models allow us to fundamentally alter the physics of a system, building understanding of causality, process uncertainty, and process feedbacks.  In this talk, I present the story of how mechanistic models of permafrost polygonal ground have evolved, providing new intuition into the key processes governing changes in Arctic landscapes.  I motivate the need for a new paradigm for modeling, where model structure and process uncertainty are addressed using the scientific method, and models are built through the incremental addition of complexity and continually evaluated with observations.  I present a sequence of multi-scale models.  First, fine-scale, observation-informed models are used to determine what processes govern local observations.  This intuition is used to design landscape scale models, and finally to parameterize global Earth System Models to improve predictions of the response of Arctic permafrost to climate change. 


Dr. Ethan Coon is a computational hydrologist in the Climate Change Science Institute at ORNL. He has a background in applied and computational mathematics, and has done research in applying computational methods for the Earth, especially land surface and subsurface processes. Broadly he is interested in process-based modeling, integrating models with data, and leverage modeling to understand the processes that govern our changing planet.

Most recently, he has developed coupled multi-physics models to explore the water cycle in a variety of applications, including Arctic permafrost evolution, watershed hydrology, flow and transport of chemical species within watersheds, and feedbacks between hydrology and other systems such as vegetation, geomorphology, and soil physics. A process-based understanding of these complicated systems often requires building understanding across scales, from pore- to continuum- to Earth system scales.

To build this understanding, Dr. Coon builds a variety of computational frameworks and software to allow easier and more efficient development of geophysical models on high performance computers. He is the principle developer of multiple open source projects, most notably the Advanced Terrestrial Simulator (ATS), and contributes to a variety of high performance computing frameworks for hybrid architectures.




Page updated January 15, 2020