Seminars

[No Seminar]

GMU Geology Faculty will give lightning talks introducing themselves, their labs, and current projects 

August 29, 2024, 4:30-5:45 pm 

Exploratory Hall 1309 and via Zoom (for link, email bhupp@gmu.edu) 

Co-hosted with George Mason Office of Research  

Jack Kaye, NASA 

Earth Science to Action: How NASA Views the Earth from Space, Air, and Ground to Advance Science and Inform Decisions 

September 4 2024, 1:00-2:30pm 

Johnson Center Cinema 

Host: Jagadish Shukla 

The Office of Research, Innovation, and Economic Impact at George Mason University invites you to attend NASA, Earth, and Space – an event featuring Dr. Jack Kaye, associate director for research of the Earth Science Division within NASA’s Science Mission Directorate, and a panel of faculty who are currently working on NASA-endorsed projects. The event will be held from 1:00 – 2:30 p.m. ET on Wednesday, September 4, in the JC Cinema. 

Dr. Kaye will share what is currently happening in space exploration and discuss future possibilities. George Mason researchers will then showcase their exemplary NASA-funded research and highlight their work, discuss outcomes, detail the impact of their research, and explain how others can collaborate or successfully apply for funding. Attendees will have the opportunity to ask Dr. Kaye and panelists questions following their remarks. 

Dr. Ben Kligman 

Smithsonian Institute, Museum of Natural History 

Title: Searching for the hidden origins of living tetrapods in Triassic equatorial Pangaea 

September 5th, 2024, 4:30-5:45 pm 

Exploratory Hall 1309 and via Zoom (for link, email bhupp@gmu.edu) 

[No Seminar this Week]

Dr. Patrick Fulton 

Cornell University, Earth and Atmospheric Sciences Department 

Title: TBD 

September 12th, 2024, 4:30-5:45 pm 

Exploratory Hall 1309 and via Zoom (for link, email bhupp@gmu.edu)  

Viviana Maggioni, George Mason University [cancelled]

Due to unforeseen circumstances, seminar is postponed to next semester.

Can Satellites Help Us Study Precipitation Patterns and Trends? 

September 18 2024, 1:30pm 

Planetary Hall 224 and via Zoom (for link, email lortizur@gmu.edu) 

Host: Luis Ortiz 

Precipitation is an essential component of Earth’s hydrologic cycle, one that influences soil moisture, vegetation growth, and streamflow. Investigating rainfall variability in space and time is crucial for sustainable water resources management, for characterizing extremes and their socioeconomic impacts, and for policymaking. This seminar presents the challenges and opportunities of satellite-based observations for studying historical precipitation patterns and trends. Satellites offer a unique perspective to look at water quantity and distribution globally everywhere anytime. Nevertheless, in order to efficiently use satellite-based observations, we need to improve the inherent coarse resolution of satellite-based observations down to finer scales and their accuracy. To address the first limitation, the seminar will present novel approaches to downscale atmospheric and hydrological variables. The gain of this shift is both practical and conceptual: not only the wealth of information generated at the finer scale vastly benefits decision-making processes, but it also allows for the study of physical processes that remain invisible at coarser scales. Estimating precipitation can be complicated by several factors, including complex orography and lack of ground references, among others. Therefore, evaluating the quality and reliability of precipitation data, before analyzing their trends and patterns, is fundamental. A comprehensive assessment of high-resolution satellite-based and model reanalysis precipitation estimates is conducted in some of the most complex regions in the world such as High Mountain Asia and West Africa 

Vivien Gornitz, Columbia University 

Recent troubling cryosphere trends, sea level rise, and New York City coastal resiliency projects 

September 25 2024, 1:30pm 

Planetary Hall 224 and via Zoom (for link, email lortizur@gmu.edu) 

Host: Luis Ortiz 

In recent years, melting of ice on glaciers and ice sheets have become the dominant contributors to sea level rise (SLR). Ice sheets, in particular, because of their ice mass and volume, will dominate future SLR. Coastal impacts will vary locally and accurate data for coastal resiliency planning becomes essential. "Recent Ice Mass Losses, Rising Seas, and New York City Coastal Resiliency Response" briefly examines global and local New York City sea level rise trends, increases in ice mass losses on both Greenland and Antarctic Ice Sheets, potential for extreme tail-end SLR, reviews future projected NYC SLR from the NPCC4 report and illustrates examples of NYC's coastal resiliency reponses. A remaining question, not addressed here, is: Will these measures suffice in the worst-case scenario?  

Dr. Terry Wilson 

Ohio State University, School of Earth Sciences 

Title: TBD 

September 26th, 2024, 4:30-5:45 pm 

Exploratory Hall 1309 and via Zoom (for link, email bhupp@gmu.edu) 

Kathie Dello, North Carolina State University

About the North Carolina State Climate Office

October 2 2024, 1:30pm 

Planetary Hall 224 and via Zoom (for link, email lortizur@gmu.edu)

Host: James Kinter

The North Carolina State Climate Office provides climate services to a diverse range of decision-makers and stakeholders. Our support ranges from the daughter planning her wedding a year out to the state agency planning large infrastructure projects, and everything in between. Our work is rooted in three mission areas: Research, Extension, and Monitoring. We produce end-user driven original research for the State of North Carolina, serve all 100 counties through Cooperative Extension, and run our own statewide mesonet. In this talk, you'll learn about one of the largest state climate offices in the country, and our approach to pragmatic climate services for all North Carolinians. 

Dr. Mattia Pistone 

University of Georgia, Department of Geology 

Title: Moho Mission to the Foundation of the Continents: The ICDP Deep Dive Drilling Project 

October 3rd, 2024, 4:30-5:45 pm 

Exploratory Hall 1309 and via Zoom (for link, email bhupp@gmu.edu) 

Meredith Parish, George Mason University

Title: Forcings of Indo-Pacific Warm Pool Climate During the Past One Million Years 

October 9 2024, 1:30pm Planetary Hall 224 and via Zoom (for link, email lortizur@gmu.edu)

Host: Xiaojing Du

The past one million years encompasses major changes in the Earth’s glacial-interglacial cycles, with a shift from 41- to 100-kyr cycles during the Mid-Pleistocene Transition (MPT), followed by an increase in interglacial CO2 across the Mid-Brunhes Transition (MBT). Terrestrial paleoclimate records spanning these climate transitions from within the Indo-Pacific Warm Pool (IPWP) are scarce, which limits our ability to diagnose the dominant climate forcings of Maritime Continent (MC) climate. We produced long, orbitally-resolved climate and vegetation reconstructions to identify the primary climate forcing mechanisms in the IPWP, a region with global importance through transport of heat to higher latitudes. We used branched glycerol dialkyl glycerol tetraethers (brGDGTs) and leaf wax isotopes (δ²Hwax, δ¹³Cwax) measured in sediment cores from Lake Towuti, Indonesia as proxies for temperature, hydroclimate and vegetation. We find that temperature variability increased after ~750 ka, coinciding with the emergence of 100-kyr cycles after the MPT. Hydroclimate exhibited significant 19-13-kyr cycles prior to the MPT, and then remained stable until the MBT (~430 ka) when significant 41- and 100-kyr cycles emerged. Insolation has long been presumed as the dominant forcing of hydroclimate in the tropics, yet our data points to glacial-interglacial cycles as the primary forcing of MC hydroclimate after the MPT. 

Dr. Brian Jicha 

University of Wisconsin-Madison, Department of Geoscience 

Title: New dating options: 40Ar/39Ar geochronology of non-traditional minerals 

October 10th, 2024, 4:30-5:45 pm 

Exploratory Hall 1309 and via Zoom (for link, email bhupp@gmu.edu) 

Gil Compo, University of Colorado, Boulder 

Title: Learning the Dynamics of El Nino and the Madden-Julian Oscillation from Data  

October 16 2024, 1:30pm 

Planetary Hall 224 and via Zoom (for link, email lortizur@gmu.edu) 

Host: Tim Delsole 

We have performed a diagnosis of the tropical Indo-Pacific climate system using an empirical-dynamical Linear Inverse Model (LIM) of weekly anomalies derived from atmospheric and oceanic reanalysis data for the 1979-2018 period. The model captures the essential features of ENSO and the MJO including their patterns and spectra, and by construction has no mean biases. The relative roles of various feedbacks in the system are diagnosed by performing a systematic set of feedback denial experiments with the model. This diagnosis suggests that the negative surface shortwave flux (SW) feedback on the SSTs (the so-called cloud shielding effect) is a dominant negative feedback on ENSO and is too weak in most climate models. The weakness of this feedback is likely behind their tendency to extend ENSO too far west into the western tropical Pacific. This compromises seasonal and longer-term predictions around the globe through spurious teleconnections. A weak SW feedback over the maritime continent is also consistent with the mean cold tongue and easterly trade wind biases of many climate models over the western tropical Pacific. Further diagnosis suggests that the magnitude of this feedback depends on the sensitivity of deep atmospheric convection and cloudiness to SST forcing, which is importantly influenced by a rectified effect (a “noise-induced drift”) of rapidly varying atmospheric diabatic and boundary layer processes. The rectification reduces the effective damping of low-level wind convergence and thence of tropospheric vertical velocities. To the extent that this rectification is too weak in models, the vertical velocities are also too weak, which contributes not only to their mean climate and ENSO biases but also to weakening the MJO in many models. 

Dr. Elizabeth Sibert 

Woods Hole Oceanographic Institute, Geology & Geophysics 

Title: A microfossil history from the bottom of the sea: sharks, fish, mass extinctions, and 85 million years of global change 

October 17th, 2024, 4:30-5:45 pm 

Exploratory Hall 1309 and via Zoom (for link, email bhupp@gmu.edu) 

Yan-Ning Kuo, Cornell University 

Title: On the contributions of anthropogenically forced and the sea surface temperature-driven regional hydroclimate change

October 23 2024, 1:30pm 

Planetary Hall 224 and via Zoom (for link, email lortizur@gmu.edu) 

Host: Erik Swenson 

Several severe droughts over the Southwestern United States (SWUS) in the past decades have caused costly socio-economic impacts. Precipitation decline is regularly identified as the main driver of the SWUS droughts, while its cause remains unclear and has often been chalked off to internal climate variability. In this talk, I will cover the evidence of how the atmospheric circulation has changed and led to the SWUS precipitation decline. Through a hierarchy of model simulations, I will demonstrate the mechanisms of this atmospheric circulation change by the anthropogenic emissions, the sea surface temperatures (SSTs, either internal or anthropogenically forced), and their interplays. 

Dr. Bruce Campbell 

Smithsonian Air & Space Museum 

Title: TBD 

October 24th, 2024, 4:30-5:45 pm 

Exploratory Hall 1309 and via Zoom (for link, email bhupp@gmu.edu) 

Annarita Mariotti, NOAA Climate Program Office 

Title: Advancing Climate Science and Services by NOAA’s Climate Program Office and Partners 

October 30 2024, 1:30pm 

Planetary Hall 224 and via Zoom (for link, email lortizur@gmu.edu) 

Host: James Kinter 

Climate is breaking every record. 2023 conditions were unprecedented. Extremes like recent Atlantic hurricanes, as well as heat waves, droughts and fires, are bringing unprecedented damages and suffering. The climate challenge has never been so great. Science and services to inform climate solutions for adaptation and mitigation have never been more crucial. 

The work of the NOAA Climate Program Office and its partners to understand and reduce the impacts of climate for the benefit of society, goes back to the beginning of the climate enterprise. The Climate Program Office plays dual roles, driving fundamental science for NOAA’s mission and ensuring science is applied and useful across a broad user base for national and global climate adaptation, mitigation, and resilience. Its programs span foundational, cross-disciplinary climate sciences, assessments, capacity building, tool development, and education. 

This talk will outline exemplary scientific challenges of direct relevance to society the NOAA Climate Program and its partners are addressing, including the understanding and predictability of extremes and phenomena across timescales and the Earth system. Effective communication and engagement methods to empower society, such as integrated information systems and regional networks, will be discussed. The emphasis will be on innovative science and services informing climate solutions for adaptation and mitigation efforts. Finally, examples of emerging and evolving factors likely to impact the climate enterprise over the next several years will be discussed. 

Dr. Kimberly Foecke 

George Mason University, Department of Sociology & Anthropology 

Title: TBD 

October 31st, 2024, 4:30-5:45 pm 

Exploratory Hall 1309 and via Zoom (for link, email bhupp@gmu.edu) 

Bärbel Hönisch, Columbia University 

Title: The ocean record of atmospheric CO2 and seawater acidity 

November 6, 1:30pm 

Planetary Hall 224 and via Zoom (for link, email lortizur@gmu.edu) 

Host: Brittany Hupp 

Michel Speiser, International Centre for Earth Simulation 

Title: Artificial Intelligence and Systems of the Earth: fundamentals and examples 

November 13 2024, 1:30pm 

Planetary Hall 224 and via Zoom (for link, email lortizur@gmu.edu) 

Host: Jagadesh Shukla 

This talk provides an overview of AI concepts with examples, based on the freshly published open access book Artificial Intelligence and Systems of the Earth. We begin with definitions of artificial intelligence, machine learning, and deep learning, explaining the building blocks of neural networks. We discuss the concepts of overfitting, regularization, dropout, stochastic gradient descent/backpropagation, and some important neural network architectures: convolutional neural networks (CNN) and transformers. Example applications include the recent deep learning models in weather prediction. The second part consists in a brief introduction to causal models, describing the concepts of causal inference and causal discovery, and how they compare to the deep learning paradigm. The illustrative example in this part involves inferring causation from time series in Earth system sciences. 

Dr. Yihang Fang 

Washington University in St. Louis, Department of Earth, Environmental, and Planetary Sciences 

Title: TBD 

November 14th, 2024, 4:30-5:45 pm 

Exploratory Hall 1309 and via Zoom (for link, email bhupp@gmu.edu) 

Keith Dixon, Geophysical Fluid Dynamics Laboratory 

Title: Questions Arising when Translating Climate Projections for use in Heat and Health Studies 

November 20 2024, 1:30pm 

Planetary Hall 224 and via Zoom (for link, email lortizur@gmu.edu) 

Host: Luis Ortiz 

Heat is one of the leading weather-related killers in the United States, resulting in hundreds of fatalities each year. Observations show an upward trend in the frequency and intensity of extreme heat events, and climate modeling studies indicate this trend will continue. Consequently, it is important for scientists, health officials, government planners, and other stakeholders to enhance their understanding of climate data and use it effectively to make informed decisions aiming to reduce risks and protect public health. However, applied researchers and stakeholders often are interested in smaller spatial scales and climate-related variables that are closely linked to factors beyond the raw output of climate model projections. Translating information about the physical climate into more relevant terms can be accomplished by incorporating prudent data processing into well-designed applied climate impacts studies. Yet, quantifying and communicating uncertainties inherent to the process can be a challenge. This talk shares insights from an ongoing effort involving a multidisciplinary partnership, including officials from the City of Philadelphia. We examine uncertainties associated with climate information as it moves through different processing stages, from climate model projections through downscaling techniques and some common methodological choices made when using the heat index as an exposure metric. 

Dr. Alexandra Villa 

University of Wisconsin-Madison & MARUM University of Bremen 

Title: TBD 

November 21st, 2024, 4:30-5:45 pm 

Exploratory Hall 1309 and via Zoom (for link, email bhupp@gmu.edu) 

Alicia Bentley, National Centers for Environmental Prediction 

Title: An Overview of Global Model Verification at the Environmental Modeling Center (EMC) 

December 4 2024, 1:30pm 

Planetary Hall 224 and via Zoom (for link, email lortizur@gmu.edu) 

Host: Austin Reed 

In order to improve the numerical models produced by the National Centers for Environmental Prediction (NCEP), model forecasts must be verified and evaluated during development and in production.  The Verification, Post-Processing, and Product Generation Branch (VPPPGB) of NCEP/Environmental Modeling Center (EMC) is responsible for the verification and evaluation of numerical models planned for and included in NCEP’s Production Suite.  As part of the verification process, model forecasts are evaluated statistically using a variety of metrics to 1) determine performance characteristics and 2) identify areas for improvement.  Forecast maps of high-impact weather, ocean, and climate events are also evaluated to determine the utility of NCEP’s numerical models in situations that impact lives and property. 
 
This presentation provides an overview of global model verification at NCEP/EMC.  The performance of NCEP's current global models will be discussed, as well as the results from past official model evaluations (which occur prior to operational model upgrades).  In addition, this presentation will provide a preview of the operational EMC Verification System (EVS), which replaced and expanded upon EMC’s previous operational verification software in March 2024.  EVS utilizes the Model Evaluation Tools (METplus) software to provide a comprehensive look at the global and regional models included in NCEP’s Production Suite.  Verification graphics produced by EVS have a consistent, publication-quality format and are shared with the broader community daily on EMC’s Verification website. 

Finley Hay-Chapman, Candidate, Doctor of Philosophy in Climate Dynamics

Title: Analyzing the Role of Land-Atmosphere Coupling Sensitivity and Subgrid Spatial Heterogeneity in Earthsystem Models

December 4 2024, 11am 

Meeting Room E, Johnson Center and via Zoom (for link see AOES outlook calendar or email  pdirmeye@gmu.edu)

Cloud formation, distribution, and other properties may be sensitive to heterogeneous surfaces depending on the strength and location of such heterogeneities and the background atmospheric state. This may drive differences in the cloud population depending on which part of the domain one is located. This may also lead to mesoscale circulations, which may strengthen or weaken this effect. Currently, climate models act on scales (~100 km) that are too large to explicitly represent these processes, which are strongest at smaller scales (around 5-40 km). Therefore, sub-grid scale (SGS) heterogeneity is neglected, and any predictability and model fidelity it may provide is lost. In this dissertation, I analyze these land-atmosphere (L-A) interactions with two new research studies.

We first introduce a novel method for diagnosing land-atmosphere coupling sensitivity on the subdaily timescale. This study defines a new metric, called the coupling sensitivity score (CSS), which uses an ensemble of single-column model runs, each with varying, prescribed surface flux conditions used as a proxy for SGS heterogeneity, and driven by observationally-constrained large-scale forcing data. The CSS can diagnose both positive [increasing cloud with wetter/cooler surface] and negative [increasing cloud with drier/warmer surface] L-A coupling sensitivity. Over the Southern Great Plains (SGP), we show that depending on the large-scale atmospheric state, strong positive or negative L-A feedback behavior may be preferred. Using the CSS this way helps to gain a better first-order understanding of L-A coupling behavior when in the presence of large variations in land surface conditions.

 In the second study, we aim to measure how well the Community Earth System Model (CESM) parameterizes SGS heterogeneity and its effect on a given model grid cell. To do this, we demonstrate a new application of the relative entropy, a metric from information theory. The relative entropy, which measures the similarity between probability density functions (PDFs), is used to measure the fidelity of statistical SGS spatial PDFs of atmospheric properties, which are parameterized within CESM, when they are compared to more realistic spatial distributions simulated by the Weather Research Forecasting – Large-Eddy Simulation (WRF-LES) model. We test the parameterized spatial distributions under four separate parameterization configurations, testing two versions each of the shallow convection/turbulence scheme and the coupling scheme. With this technique, we show that a new, augmented version of the shallow convection/turbulence scheme, CLUBB+MF, marginally outperforms its default version, CLUBB when using the WRF-LES simulations as a target.

The methodologies from these two studies are also applied to two other locations, each with a different hydroclimate than the SGP: one with much higher moisture availability in the Amazon tropical rainforest, and one in the semi-arid north central region of Argentina. Analyzing these new hydroclimates shows that both the CSS metric and our relative entropy method have generable applicability outside of the SGP, and may be used to further understand L-A coupling behavior in the presence of SGS heterogeneity and how we may improve its simulation in today’s state-of-the-art earth system models.

Dr. Sumit Mishra 

Universidad Nacional Autónoma de México, Institute of Geology 

Title: The genesis of manganese deposits in Jalisco, Mexico: Geological insights and mineralogical signatures 

December 5th, 2024, 4:30-5:45 pm 

Exploratory Hall 1309 and via Zoom (for link, email bhupp@gmu.edu)