September 9, 2022 at 3:00 pm (PLS 1140)
Welcome new students! In this first Colloquium of the academic year, faculty will give two-minute flash talks to introduce themselves and their research. The talks will be followed by snacks and games in the Chemistry courtyard. Feel free to bring your favorite yard games and board games!
Parvathy Prem, Johns Hopkins Applied Physics Laboratory (APL)
The Once and Future Lunar Atmosphere: Modeling the Moon's Water Cycle
September 16, 2022 at 3:00 pm (PLS 1140)
One of the most significant discoveries in planetary science over the past two decades has been the detection (by several different instruments) of water on the Moon - not only in cold, permanently shadowed craters near the poles, but also on the sunlit lunar surface. Where does this water come from? What does it tell us about the history of our solar system neighborhood? Could it ever be a resource for planetary exploration? Several upcoming orbital and landed missions will explore those questions in more detail over the coming decade. This presentation focuses on recent investigations into past, present, and future sources of water (and other volatiles) on the Moon, and how volatiles may move across and between the lunar surface and exosphere.
Today, the density of the lunar atmosphere is so low that molecules rarely collide with each other. However, for brief intervals of time in the past, volatile-rich impacts and volcanic eruptions may have temporarily transformed this thin, collisionless exosphere into a rarefied but collisional temporary atmosphere, with water vapor as a key component. Less dramatic, but still significant, transformations of the lunar exosphere also occur today, when water and other exhaust gases are released during spacecraft descent and landing, temporarily increasing exospheric density above background levels. We will discuss results from numerical modeling of some of these scenarios, and the implications for science and exploration.
Anna Karion, NIST
The NIST Greenhouse Gas Urban Testbed System: Recent results and challenges in urban greenhouse gas emissions estimation
September 23, 2022 at 3:00 pm (PLS 1140)
Three urban testbeds have been established by the National Institute of Standards and Technology (NIST) Greenhouse Gas Measurements Program in Indianapolis, Los Angeles, and Washington/Baltimore. These are collaborative multi-institution projects (including federal agencies, universities, and the private sector), combining atmospheric measurements and analysis to estimate urban greenhouse gas (GHG) emissions and related uncertainties. GHG’s are measured from dense high-accuracy tower networks and during periodic aircraft campaigns. Each testbed hosts additional observations and analyses aimed at quantifying GHG emissions, often complemented by outside researcher-led campaigns that leverage existing long-term monitoring.
Here we present an overview of each testbed along with recent scientific results, ongoing measurements, and future plans for the system. The goal of the testbed system is bringing emissions estimates derived using various methodologies into consensus. We show examples of such compatibility between estimates in Indianapolis, evidence of emissions reductions during the COVID-19 shutdown in March and April of 2020 in both Los Angeles and Washington, DC, and more recent work on long-term methane trends in Washington DC and Baltimore, Maryland. We also highlight the largest sources of uncertainty in our emissions estimates.
Sue Brantley, Penn State University
Helz Special Seminar: Subsurface Landscapes of Oxidation and Reaction in the Critical Zone
October 3, 2022 at 4:30 pm (ESJ 0224)
Water, gas, and biota interact with bedrock to create and maintain the mantle of altered material known as regolith at Earth’s surface. The regolith mantle nurtures human and non-human ecosystems and affects water flow and storage. However, our understanding of how regolith forms from bedrock is poor at best. One reason for this is that regolith is controlled by the many coupled geological, chemical, physical, and biological processes occurring within the zone extending from the outer edge of the vegetation canopy to the depths of groundwater (the critical zone). An additional characteristic of regolith that is difficult to treat but important to the critical zone is the extreme heterogeneity of weathered and unweathered materials. In this talk I discuss the use of geochemical and geophysical tools to learn how the deep architecture of the critical zone – including the distribution of subsurface reaction fronts developed through weathering reactions – may control water storage and flow. The long-term goal is to stop treating the subsurface as a black box but to begin to understand how it acts as a (self-organizing?) system that we can understand and protect.
Martha Gilmore, Wesleyan University
October 21, 2022 at 3:00 pm (PLS 1140)
Karla Núñez, UMD
Justice in Geoscience Workshop
October 28, 2022 at 3:00 pm (PLS 1140)
James (Jim) Schiffbauer, University of Missouri
November 11, 2022 at 3:00 pm (PLS 1140)
Sally June Tracy, Carnegie Earth and Planets Laboratory
November 18, 2022 at 3:00 pm (PLS 1140)
The coordinator for the Colloquium Series is Dr. Megan Newcombe. You can contact her at firstname.lastname@example.org.