Seminars

Aasma Acharya, Master of Science in Climate Science

Assessing the Surface Urban Heat Island and Urban Extreme Precipitation Anomalies: An Analysis of Richmond, Virginia

Fri, 18 Jul, 10:30am via zoom (email zboybeyi@gmu.edu)

Advisor: Zafer Boybeyi

Urban areas exhibit elevated surface temperatures compared to surrounding regions due to dense built-up surfaces that retain heat. This phenomenon, known as Surface Urban Heat Island (SUHI), influences atmospheric processes and modifies local precipitation patterns. Existing studies has explored urban temperature anomalies and enhancement of precipitation intensity and frequency, particularly downwind of cities. However, limited research has examined how the local extreme precipitation patterns relate to varying levels of urban heat anomalies. This study evaluates the spatial distribution of summertime urban extreme precipitation in a midsized U.S. city, Richmond, Virginia. Using high-resolution hourly precipitation (4 km/hourly) and land surface temperature (5 km/hourly) datasets for the period of 2011–2021, we investigate the intensity and frequency of extreme rainfall events under strong SUHI conditions. We observed a consistently elevated intensity of SUHI over the Richmond urban core, with peak anomalies occasionally exceeding 5°C during the afternoon. The strongest SUHI effects were aligned with high-density built-up areas of Richmond and its suburbs. Composite analysis reveals localized extreme precipitation, with intensities over 26 mm/hr, occurred most frequently southeast of Richmond under strong SUHI conditions, which is downwind of the urban core in the 700 hPa prevailing wind field. Under SUHI > 99th percentile conditions, a hotspot with hourly rainfall intensities exceeding 67 mm/hr was observed in the same downwind region. A maximum of 78 hourly exceedances above 8.5 mm/hr was recorded directly over the Richmond urban core, extending into the downwind region. In contrast, most of the upwind region showed no more than 30 exceedances. This suggests that the downwind region experienced repeated extreme precipitation events likely influenced by afternoon convection. While large-scale atmospheric systems may influence regional rainfall, the consistent localization of extremes in the southeastern urban core and downwind region suggest a thermally driven enhancement linked to urban heating. These findings highlight the impact of urban surface properties in influencing extreme precipitation and support the hypothesis that SUHI contributes to localized convective intensification downwind of midsized inland cities.

Scott Knapp, Doctor of Philosophy in Climate Dynamics

Sea Surface Temperature Gradients of the Pacific in Warm Climates

Mon, 21 Jul, 10:30am, Exploratory Hall rm 3301

Advisor: Natalie Burls

The sea surface temperatures (SST) of the Pacific Ocean have extremely important roles in setting global weather and climate. The relative SSTs of the east and west tropical Pacific affect large-scale atmospheric circulation like the Walker cell, while the relative SSTs of the tropical and subtropical Pacific affect the Hadley circulation. Both the Hadley and Walker influence global temperature, hydroclimate, poleward energy transport and radiation balance. It is not yet understood exactly how SST in the Pacific will change with global warming. This uncertainty is intricately related to the large spread of global warming predicted by different climate models. We aim to increase our understanding of how Pacific SSTs will change in the short and long term in response to greenhouse gases by studying regional changes of dynamic and radiative processes. We explore the coupled ocean-atmosphere relationship between regional

radiative feedback and large-scale SST gradients using a simplified box model forced with an abrupt quadrupling of atmospheric CO2 concentrations. The sensitivity of zonal and meridional upper ocean temperature (TUO) gradients to regional feedback parameter (λ) configurations is tested by simulating 1296 combinations of regional λ. We identify thresholds of λ differences between regions which are strong enough to allow the regional radiative response to overcome the TUO gradient weakening tendencies of the oceanic and atmospheric energy transport in the box model. We next quantify how transient changes in the zonal Pacific SST gradient (the thermostat mechanism) and transient versus equilibrium changes in global mean λ (the “pattern effect”) are related between models and to each other, and to the global mean surface temperature change at equilibrium resulting from a doubling of CO2 in CMIP6.

Mary Korendyke, Doctor of Philosophy in Climate Dynamics

Holistic Forecasting of z500: A Combined Oscillation-Regime Framework

Mon, 21 Jul, 1:00pm, Exploratory Hall rm 3301

Adviser: David Straus

The difficulty in predicting the atmospheric circulation and weather beyond two weeks in advance arises because the predictability arising from knowledge of the initial conditions becomes small, while the information that comes from knowledge of the boundary conditions (such as tropical ocean temperatures) is useful on seasonal time scales. Improving the skill of weather prediction in the 2-4 week range would provide useful and actionable information for decision makers in many sectors of society, from water managers to forestry officials to emergency response planners. However, achieving that level of skill requires that traditional techniques used for forecasting the weather out to 10 days must be augmented by statistical techniques. Different techniques have been independently investigated in the literature for potential weather forecasting skill in the 2-4 week range. Each has strengths and weaknesses. In this dissertation, I use fundamental oscillations in the atmosphere to enhance a statistical model trained on the past evolution of large scale atmospheric patterns. These oscillations can be interpreted in terms of preferred patterns and results from this model can be interpreted in terms of circulation regimes. I analyze the strengths, weaknesses, and potential increase in weather forecasting skill of this enhancement to determine the viability of such holistic forecasting methods for the 2-4 week range.

Bilal Haq, Sarbonne University & GMU AOES 

Advances in our understanding of Sea Level Variations in Deep 

Time Thu, 23 Jan, 4:30pm 

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

Viviana Maggioni, George Mason University 

Can Satellites Help Us Study Hydrologic Patterns and Trends? 

Wednesday, 29 Jan, 1:30pm 

Innovation Hall 134 and via Zoom (for link, email bklinger@gmu.edu) 

Host: Luis Ortiz 

Investigating hydrologic variability is crucial for sustainable water resources management. This seminar presents the challenges and opportunities of satellite-based observations for studying precipitation patterns and trends. Satellites offer a unique perspective, but we need to improve the resolution and accuracy of satellite-based observations. The combination of satellite observations and model simulations generates a measurement that is more accurate than either. This seminar will explore the potential of assimilating a suite of satellite products in land surface models to improve our estimation and understanding of terrestrial carbon-water-energy cycle processes. It will also present novel approaches to downscale atmospheric and hydrological variables. This shift  vastly benefits decision-making processes, but also allows for the study of physical processes that remain invisible at coarser scales. Last, the seminar will focus on the analysis of past and future precipitation patterns and trends across different regions of the world, including the Contiguous United States and West Africa. 

Matthew Jones: An overview of research on emerging subsurface energy technologies at the U.S. Geological Survey

Title TBD 

Thu, 30 Jan, 4:30pm 

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

Eunkyo Seo, Pukyong National University 

Misrepresentation of land-atmosphere interactions due to model fidelity in capturing diurnal precipitation  

Wed, 5 Feb, 1:30pm 

Innovation 134 and via Zoom (for link, email bklinger@gmu.edu) 

Host: Paul Dirmeyer 

The accurate representation of diurnal precipitation is critical for understanding land-atmosphere interactions and their impact on hydrological and energy cycles, but most current research relies on daily averages. This study investigates the systemic phase shift in diurnal precipitation in reanalysis datasets (e.g., ERA5, MERRA2, JRA-55, etc.), which typically occur earlier than peaks from observations. We explore the effects of this early peak on soil moisture climatology and land-atmosphere coupling processes. Results indicate that the early precipitation peak leads to surface cooling, suppressed upward longwave radiation, and increased latent heat flux, ultimately resulting in drier soil moisture climatology over the mid-latitude. Additionally, the early peak strengthens land-atmosphere coupling. This highlights the necessity of resolving diurnal cycles in model physics to mitigate biases in land surface reanalysis datasets and improve the reliability of modeled land-atmosphere interactions. 

Brian Huber, Smithsonian National Museum of Natural History

Environmental consequences and rapid biotic evolution after the asteroid impact that killed the dinosaurs

Thu, 6 Feb, 4:30pm

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

Philip Orton, Stevens Institute of Technology 

Why do tropical cyclone disasters surprise us in the mid-latitudes?  Insights from probabilistic and dynamical flood modeling 

Wed, 12 Feb, 1:30pm 

Zoom Only (for link, email bklinger@gmu.edu) due to mid latitude storm activity

Host: Luis Ortiz 

A fundamental challenge with mid-latitude coastal storm hazard assessment is that tropical cyclones (TCs) cause the largest events but occur too infrequently to infer reliable hazard probability distributions. As a result, observation-based assessments of TC hazards typically merge TCs with far more numerous extra tropical cyclone (ETC) data, despite large differences between TCs and ETCs. 

First, I will demonstrate this challenge using synthetic storm surge data. Extreme value analysis (EVA) using merged TC and ETC data results in low-biased estimates of extremes. Separating storm types can eliminate this bias but suffers from greater random error. Longer datasets or model-based synthetic data can help reduce this error. 

Second, I will show how the threat of these TC “outlier” events can be accentuated by compounding hazards.  Results again show that TCs have unique characteristics and dominate the joint probabilities of the most extreme rain-surge compound events. 

Jessica DePaolis, Virginia Tech

Investigating the Tectonic and Environmental History of the Eastern Pacific: Splay faults, Turbidites, and the Bering Land Bridge

Thu, 13 Feb, 4:30pm

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

Molly Patterson, Binghamton University

Catchment Sensitivities of the West and East Antarctic Ice Sheets to Orbital Forcing During the Mid- to Late Pliocene

Thu, 20 Feb, 4:30pm 

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

Host: Brittany Hupp 

Julie Rozenberg, World Bank 

Modeling climate resilience in infrastructure systems 

Wed, 26 Feb, 1:30pm 

Innovation 134 and via Zoom (for link, email bklinger@gmu.edu) 

Host: Edward Oughton & Luis Ortiz 

This talk will give an overview of several papers and a book that lay out a framework for understanding infrastructure resilience—the ability of infrastructure systems to function and meet users’ needs during and after a natural shock—and that makes an economic case for building more resilient infrastructure. The talk will focus on models to assess the propagation of climate shocks through infrastructure networks and to prioritize infrastructure investments, but will also discuss broader sets of interventions that increase the resilience of infrastructure users to climate shocks. 

Daven Quinn, University of Wisconsin-Madison as the speaker

TBD

Thu, 27 Feb, 4:30pm 

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

Jun Wang, NOAA National Center for Environmental Prediction 

Machine Learning Development for Global Weather and Climate Forecasts. 

Wed, 5 Mar, 2:00pm [note new time]

Virtual only via Zoom (for link, email bklinger@gmu.edu) 

Host: Ben Cash 

Penny Wieser, University of California-Berkeley

Fluid inclusions: Unveiling the Secrets of Magma Storage at Ocean Island Volcanoes and Enhancing Rapid Response to Volcanic Eruptions

Thu, 6 Mar, 4:30pm 

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

Cristina Stan, George Mason University 

Improving the Predictability of the Madden-Julian Oscillation at Sub-seasonal Scales with Gaussian Process Models  

Wed, 19 Mar, 1:30pm 

Innovation 134 and via Zoom (for link, email bklinger@gmu.edu) 

Matt Huber, Purdue U 

Hot Tub Time Machine: Lessons Learned on the Future of Moist Heat Stress from Earth’s Past  

Wed, 26 Mar, 1:30pm 

Innovation 134 and via Zoom (for link, email bklinger@gmu.edu) 

Host: Paul Acosta 

Julia Cisneros, Virginia Tech 

Shaped by Nature: Bedforms as Windows Into Environmental Systems 

Thu, 27 Mar, 4:30pm 

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

Cathy Li, Pacific Northwestern National Laboratory 

Urban Climate-Energy Interactions from Global to Local Scales 

Wed, 2 Apr, 1:30pm 

Innovation 134 and via Zoom (for link, email bklinger@gmu.edu) 

Host: Luis Ortiz 

Our climate and energy systems are closely intertwined through complex interactions. Urban energy consumption both drives and is affected by anthropogenic climate change. Previous studies have predominantly examined the global scale interactions between energy use and future warmer climates. However, the local scale interactions between urban energy use and the urban climates are frequently ignored in future energy projections, due to methodological, scale, and computational challenges. These local interactions can have global scale effects. In this talk, I will first show that ignoring such interactions underestimates climate-driven energy risks on global to local scales, which necessitates explicit and dynamic modeling of urban climate–energy interactions for climate-sensitive energy planning. I will then discuss several recent advancements in global urban energy modeling in Earth system models, which help unveil the effects of socioeconomic development, changing humidity conditions, as well as large-scale building electrification on urban climates and energy demand in a changing climate. 

Terry Wilson, Ohio State University 

Weighing the Antarctic Ice Sheet 

Thu, 3 Apr, 4:30pm

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

Ning Zeng, U Maryland 

Wood Vault: Burying woody biomass for carbon sequestration -- a simple idea that actually works

Wed, 9 Apr, 1:30pm 

Innovation 134 and via Zoom (for link, email bklinger@gmu.edu) 

Host: Jagadish Shukla 

To permanently sequester a large amount of CO2, planting trees is not enough. In an established forest, some trees absorb CO2, but other trees die, decay and release carbon back into the atmosphere. Wood Harvesting and Storage (WHS) proposes tree harvesting or waste wood collection, followed by secure storage in engineered structures called Wood Vault to prevent decomposition. The net effect is to remove CO2 from the atmosphere at up to 1/4 of our current emission rate. Demo projects show a durability of centuries, and a cost of $10-50 per ton of CO2. The technique is low cost, distributed, easy to monitor, safe, and creates green jobs, thus adding to the 'toolbox' of climate change mitigation. The burgeoning industry of Carbon Dioxide Removal (CDR) is implementing WHS commercially, opening a new research subject. 

Jennifer Kasbolm, Carnegie Institution for Science 

Calibrating Timescales and Measuring pCO2 to test the role of Columbia River Basalt volcanism in the Miocene Climate Optimum

Thu, 10 Apr, 4:30pm 

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

Jagadish Shukla, George Mason U

Origins of Ideas for Modern Reanalysis, Dynamical Seasonal Prediction, and L in COLA: A Personal Retrospective 

Wed, 16 Apr, 1:30pm 

Innovation 134 and via Zoom (for link, email bklinger@gmu.edu) 

This seminar has two parts. The first part is to thank my students, professors and research colleagues at MIT, GSFC/NASA, UMD, COLA, GMU, and other research centers in the world with whom I had the privilege of working during the past five decades. 

The second part of the seminar was inspired by a question one of the students asked me some time ago, “How did you get research ideas?” The same question was asked by my collaborator, Ashley Stimpson who helped me write my memoir, “A Billion Butterflies: A Life in Climate and Chaos Theory”. The seminar will give a brief personal retrospective of the origins of ideas for modern reanalysis, dynamical seasonal prediction (DSP), and the importance of land surface processes for modelling and prediction of weather and climate.  

During the mid-20th Century, the butterfly effect and the limits of weather predictability were the dominant paradigms, indicating that dynamical seasonal prediction would not be possible. Yet the demonstration of significant impacts of slowly varying boundary conditions of sea surface temperature and soil wetness using fledgling climate models of early 1980s provided a scientific basis for research on dynamical seasonal prediction (DSP). This led to the establishment of Centre for Ocean – Land – Atmosphere Studies to demonstrate the feasibility of societally beneficial dynamical seasonal prediction. At the same time, several weather and climate prediction centers began to produce seasonal forecast with prescribed and persistent boundary conditions of sea surface temperature. Within a decade, global coupled Ocean-Atmosphere models succeeded in simulation and prediction of sea surface temperature for 1-2 seasons, and DSP became operational like NWP. 

Reanalysis products have now become an indispensable data source for weather and climate research and have recently been important for training artificial intelligence (AI)/machine learning (ML) models. There are several national and international research programs and field experiments for measurements and parametrizations of land surface processes demonstrating the importance of land surface processes in enhancing predictability of sub-seasonal and seasonal variations of weather and climate. 

Nadine McQuarrie, University of Pittsburgh 

Influence of Tectonics, Climate and Drainage Basin Capture on Canyon Incision in the Peruvian Andes

Thu, 17 Apr, 4:30pm 

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

David Hoppe, Earth System Science MS Thesis Defense

A large Cetotherid (Cetacea, Mysticeti) from the Late Miocene of Calvert Cliffs, Maryland, USA

Fri, 18 Apr, 10:30am, Exploratory Hall 1309

Advisor: Mark Uhen

Madison Thompson, Earth System Science MS Thesis Defense

Ediacaran ocean oxygenation: Insights from the Portfjeld Group, North Greenland

Fri, 18 Apr, 2:00pm, Exploratory Hall 1309

Advisor: Geoff Gilleaudeau

Rocks of the Ediacaran Period record the emergence, rise, and subsequent downfall of the Ediacaran biota, Earth’s oldest known communities of complex macroscopic organisms. This pivotal period of Earth history is also characterized by significant shifts in the global carbon cycle, with middle Ediacaran carbonates worldwide recording one of the largest negative δ¹³C excursions in the geologic record, known as the Shuram-Wonoka Excursion (SWE), from 579 to 564 Ma. While the relationship between negative δ¹³C anomalies and biological innovation remains poorly understood, recent data suggests that a transient interval of widespread ocean oxygenation during the SWE could be an environmental link between these phenomena. However, Ediacaran-age rocks that are fossiliferous and conducive to carbonate-based paleoredox analysis are exceedingly rare. The Portfjeld Group of North Greenland is an Ediacaran to Lower Cambrian carbonate succession, which records a large negative δ¹³C anomaly of ~−12‰ that has been correlated with the SWE. The Portfjeld Group also contains exceptionally well-preserved microfossils, including putative phosphatized animal-like eggs and embryos comparable to the Weng’an biota in South China. Here, we present a new carbonate uranium isotope (δ²³⁸U) record of the Portfjeld Group as a proxy for global ocean redox during the SWE. In the interval prior to and during the early decreasing limb of the δ¹³C excursion, δ²³⁸U values are very low (median = −0.72‰), indicating widespread global ocean anoxia. However, as δ¹³C values rapidly drop from ~−2‰ to ~−8‰, there is a pronounced shift towards higher δ²³⁸U values (median = −0.16‰, indistinguishable from modern carbonates). Overall, our data indicate a transient episode of near-modern levels of global ocean oxygenation during the SWE. Notably, the animal-like egg and embryo fossils in the Portfjeld Group are stratigraphically well below the positive δ²³⁸U shift (as is the case in South China). Our findings suggest that there was not a simple cause-and-effect relationship between ocean oxygenation and the evolution of complex organisms during this time, and that other local or global factors influenced the appearance and preservation of these organisms.

Jordan Abell, Lehigh University

No iron fertilization of the Pliocene North Pacific  

Wed, 23 Apr, 1:30pm 

Innovation 134 and via Zoom (for link, email bklinger@gmu.edu) 

Host: Natalie Burls and Po Ju Chen 

H. Annamalai, U Hawaii 

Monsoon-induced unprecedented extremes over driest regions of South Asia:  

Process-based understanding of the Pakistan flood of 2022 

Tue, 29 Apr, 1:30pm – note special day 

Exploratory 1309 and via Zoom (new link, email ikinter@gmu.edu ) 

Host: Jim Kinter 

During the 2022 Asian summer monsoon, the climatological driest parts of southwestern Pakistan and the northern Arabian Sea (regions of climatological heat low, H_LOW) experienced unprecedented precipitation (>500% of the normal) whereas precipitation was reduced from the Indo-Gangetic Plain to the tropical western Pacific. Its causes are examined with process-oriented diagnostics applied to reanalysis (ERA5), and numerical experiments with a linear atmospheric general circulation model. Model solutions confirm that the weakened large-scale monsoon is determined by warm SST and enhanced precipitation over the eastern Indian Ocean and Maritime Continent. Rossby waves from those regions then deepen the H_LOW. The resultant horizontal pressure gradient between H_LOW and northern India drives low-level wind anomalies that precondition the lower troposphere during June, and drive the unprecedented precipitation during July–August.  We will also discuss the monsoon response to nearly identical tropical forcing observed during 2010 and 2020, and the monsoon response over southwest Pakistan.  

Hsin Hsu, Princeton U 

Terrestrial Hydrology Changes Under a Warming Climate: Insights from Daily Data 

Wed, 23 Apr, 1:30pm 

Innovation 134 and via Zoom (for link, email bklinger@gmu.edu)  

Host: Paul Dirmeyer 

Changes in terrestrial hydrology in a warming climate have important implications for freshwater availability, climate regulation, and societal risks. Much of our understanding has relied on monthly data, but daily variations in intermittent water fluxes can be important. For instance, in modern climate models (CMIP6), warming dries soils despite increasing precipitation. I use daily hydrologic data to find an alternative explanation for this divergence: increasing unevenness in daily precipitation enhances surface runoff, thereby reducing total soil moisture. Next, I identify two main pathways driving changes in evapotranspiration: (1) the moisture-redistribution pathway, based on daily soil moisture, and (2) the energy-demand pathway, based on altered energy availability under climate change. I highlight numerous regions where the pathways driving evapotranspiration changes in CMIP6 diverge from those in reanalysis. 

TBD 

Thu, 1 May, 4:30pm 

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

Efi Foufoula-Georgiou, U California, Irvine 

Precipitation in the Earth System: 

Global estimation, precipitation extremes relevant to hazards, and climate change 

Wed, 7 May, 1:30pm 

Innovation 134 and via Zoom (for link, email bklinger@gmu.edu) 

Host: Jagadish Shukla 

Under global warming, precipitation is expected to change in complex ways, including the frequency and magnitude of extremes.  I will present recent results on: (1) global precipitation estimation from multi-satellite observations in places lacking ground measurements, and (2) assessment of the change of the space-time structure of storms under global warming.  We combine instantaneous Passive Microwave (PMW) satellite snapshots with the dynamical temporal information provided by GEO IR satellites, to capture extremes and provide uncertainty quantification.  We analyze the cold-season precipitation over the western United States in the WRF model at 6 km and 1 h resolution in the historical period and pseudo-future simulations under the high emission RCP8.5 scenario. We demonstrate that global warming will induce a “sharpening” of storms both in time and space, meaning that a larger proportion of rain will fall over fewer wet hours and over smaller areas, amplifying hazard potential for flooding and post-fire debris flows. 

Myong-In Lee, Ulsan Institute of Science and Technology 

Distinctive features of the Summer Arctic Oscillations and its implications for the East Asian Heatwave 

Wed, 14 May, 1:30pm 

Innovation 134 and via Zoom (email bklinger@gmu.edu for link) 

Host: Nakbin Choi 

The Summer Arctic Oscillation (SAO) has a potential influence on extreme heat events in East Asia, contributing an estimated 5.5 additional days to the severe 2018 South Korean heatwave. The seminar highlights an emerging upper-tropospheric teleconnection pattern associated with the SAO, which has intensified since the late-1990s. This pattern plays a dominant role in modulating anticyclonic circulation over East Asia, surpassing the influence of ENSO during boreal summer. SAO exhibits a distinct spatial structure, with its core variability centered poleward of near 75N, and may originate from wave forcing in the near-Arctic. Additionally, the summer Arctic cloud radiative effect—characterized by a positive shortwave response—points to the importance of moist processes and cloud response in maintaining SAO variability. The observed equatorward expansion of SAO-related influences further underscores the necessity of investigating wave-mean flow interactions specific to the summer season. 

[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)