Current Visiting Fellows
Atmospheric Epistemologies - ways of creating knowledge about cloud seeding
As seen most recently during the Covid-19 pandemic, science literacy has experienced a drastic decline amongst the general public. While this concern has been brought to the forefront of public debate now more than in the past, science literacy of the general public has been experiencing a dramatic decline for decades, across the board of scientific fields. Specifically, cloud seeding has been targeted in a larger conspiracy theory narrative that claims meteorologists and politicians are working hand in hand, falsifying and controlling science against the greater good. This has, in turn, led to global mass protests against what protesters are calling ‘geoengineering’. These misplaced civil society efforts end up slowing down scientific progress and deepen the divide between the general public and their capacity for greater science literacy. The project revolves around the concept of atmospheric epistemologies, or ways of making knowledge about clouds and the atmosphere. The project is a mirrored ethnography that analyzes, on the one hand, the ways in which scientists produce knowledge about cloud-seeding and the atmosphere, and, on the other hand, ways in which the general population produce knowledge about the same topics. The project offers a new approach to STS, as well as the study of knowledge production in two communities that are epistemologically opposed.Dr. Cotofana is coming to CU to work with Matt Burgess on exploring how political polarization affects the views of scientists and citizens of cloud seeding as a method of combating drought. Colorado, as a state that invests in cloud-seeding technology, has substantial political diversity, and also houses some of the world's leading climate science hubs, is an ideal place to study this. Dr. Cotofana will be conducting interviews with scientists and citizens during her time here. She will also be interacting with other scholars in the Center for Social and Environmental Futures.
The role of the 'cloud twilight zone' in Earth's energy budget
Clouds play a dominant role in Earth's energy budget as they cover more than half of the globe and strongly interact with both solar and terrestrial radiation. Nevertheless, they are poorly understood and represented in models and hence cause high uncertainty in climate prediction. The study of clouds’ processes by remote sensing and quantification of their radiative effects are based on a binary separation between clouds and clear skies that contain aerosol particles. This separation is ambiguous in practice as humidified aerosols continuously grow to become cloud droplets by condensation of water vapor. Moreover, the radiative signal of aerosols and cloud droplets has been shown to overlap and was named the “cloud twilight zone” (CTZ). Eshkol Eytan will work with Graham Feingold, Jake Gristey, Jennifer Kay, and Rainer Volkamer. The studies will use modeling and remote sensing data to quantify the effects of the CTZ on the global energy budget and to study the contribution of different processes to the total CTZ radiative effect. This will help to advance our understanding of clouds’ role in the energy budget and improve remote sensing areas that are neighboring clouds.
Understanding the nucleation of aseismic creep events
Not all faults slip solely in earthquakes – some have measurable offsets which cannot be attributed to earthquakes thanks to a process called creep. Fault creep was first identified over 60 years ago, and since then, many different fault behaviors have been identified. A particularly interesting observation is that creeping faults do not accumulate slip uniformly in time but instead in bursts of slip known as creep events. Creep events are typically a few hours to days in duration, occur every few weeks to months and have displacements of a few millimetres. These bursts of slip have been observed to occur on faults in California (e.g., San Andreas, Hayward and Calaveras Faults) as well as the North Anatolian Fault, Turkey. Despite knowing about these creep events since the late 1950s, we still do not know what causes them to nucleate or how they relate to other slow earthquake processes. Dan will work with Roger Bilham to investigate active creeping faults in California and beyond, using and developing a variety of geodetic instruments to understand the nucleation of creep events and determine how their moment and duration scale with one another.
Understanding climate impacts of a changing Pacific
Ulla will work with Kris Karnauskas and Ben Livneh on understanding climate impacts from large scale changes in ocean and atmospheric circulation with particular focus on changes in the tropical Pacific and climate impacts in the Americas. Recent observations have revealed a multi-decadal strengthening of the Walker circulation in the tropical Pacific, yet climate models robustly predict a weakening of the Walker cell emerging in the 21st century. How such a potential future reversal of the Walker cell trend will impact society through changes to regional hydrology, fire susceptibility, and extreme events is, however, largely unknown, which poses a big challenge for adaptation and mitigation strategies. Through a hierarchy of modelling experiments, this project aims to address this knowledge gap by developing a framework which traces the effect of large-scale circulation changes on societally relevant climate impacts. An additional component of the project, in collaboration with Anne Gold, is to present outcomes of this research in education and outreach in communities affected by climate change impacts across Colorado.
Prediction of dynamic sea ice deformations in the Southern Ocean using the ensemble of large-scale and small-scale remote sensing data
In the Southern Ocean, the dynamic drift and deformation of sea ice play an important role in the distribution of sea ice mass balance, along with the thermodynamic freezing and melting. However, the detailed mechanisms of the formation of pressure ridges or leads have not been fully understood due to the lack of high-resolution sea ice height measurement data. Recently, NASA’s ICESat-2 altimeter made it possible to capture the characteristics of individual sea ice deformation features and their regional statistics. Moreover, various satellite products besides ICESat-2, including passive microwave and synthetic aperture radar, provide sea ice drift on both large and small scales. Younghyun Koo will work with Dr. Walter Meier to combine these multiple satellite data and examine how atmospheric/oceanic forces and sea ice kinematics impact the formation of sea ice dynamic features. In addition, he will develop machine learning models to predict how the dynamic conditions of the Antarctic sea ice will change as the global climate changes.
Building political coalitions for climate mitigation through economic opportunity: a model of household opinion and migration
Mitigating the consequences of climate change and reducing political polarization are two of the biggest problems facing society today. These problems are intertwined, since meeting international climate-mitigation targets requires implementing policies that accelerate the rate of decarbonization, and these policies can succeed only with widespread bipartisan support. Ekaterina will work with Matt Burgess to provide a road map for how to build momentum for climate action and counteract polarization around climate policies. She will study this problem through the lens of economic opportunity and migration in the United States. While concerns about the cost of decarbonizing and job loss in the fossil fuel energy sector have been barriers to clean energy policies, recent forecasts show that the transition to clean energy could be cheaper and faster than previously thought. The economic opportunity created by the low cost of clean energy is interwoven with the patterns of state-to-state migration in the U.S., which is often driven by economic factors. The goal of the project is to evaluate how the geographic siting of renewable energy projects can affect political support for climate change mitigation.
Identifying the climate drivers of decadal variability in tide gauge records
Decadal climate variability influences the frequency and severity of natural hazards (e.g., drought) with considerable human and ecological impacts. Interpreting past variability and predicting future impacts relies upon an understanding of the underlying physical processes, as well as any changes in these processes over time. However, identifying such changes requires long observational records. In this respect, coastal sea level records from tide gauges are uniquely valuable. Such measurements provide a record of climate change over the last century (and, in a few places around the globe, since the 18th century). In recent papers, Chris has documented dramatic increases in coastal sea level variability in the second half of the 20th century, in widely-separated geographic locations. While in Boulder, he will work with Drs. Kris Karnauskas, Antonietta Capotondi, and Steve Nerem to identify the ocean and atmospheric dynamical mechanisms underlying decadal sea level variability and its changes through the 20th century.
Using Distributed Acoustic Sensing to Monitor Induced Seismicity and Evaluate Seismic Hazard in Paradox Valley, Colorado
Deep injection of wastewater fluid associated with oil and gas production is known to be responsible for the triggering of earthquakes near dense population centers. This practice increases the seismic hazard for regions that are typically devoid of earthquakes and poses a risk to buildings and critical structures where appropriate safety measures are deficient. To address this, I will work with Anne Sheehan and Ge Jin (CSM) in utilizing a novel seismological technique known as distributed acoustic sensing (DAS), in Paradox Valley, Colorado, to improve our understanding of induced seismicity where conventional seismic networks may be insufficient or absent. DAS operates by using an opto-electronic system that emits pulses of light down a fiber optic cable and records naturally backscattered energy returning from varying segments. In essence, this instrument acts as a dense and mechanically flexible seismic array that consists of multitudinous broadband sensors sensitive enough to detect tiny subsurface strain events in high fidelity. We aim to exploit the capabilities of DAS to identify key features missed by the surrounding (yet sparse) network of seismometers in Paradox Valley; features that can offer more detailed and accurate information on the evolution of faults and stress transfer mechanisms that drive the induced seismicity phenomenon.
Determining the required resolution to represent the impact of polar lows on the ocean
Polar lows are small and short-lived intense maritime cyclones that develop at high latitudes during the cold season. The strong winds associated with polar lows, combined with the large temperature difference between the sea surface and the atmosphere, leads to a large heat transfer from the ocean to the atmosphere. Despite the potential impact of polar lows on the ocean circulation, the current global climate models are too coarse to correctly represent them. Marta will work with John Cassano, Mark Serreze and Amy Solomon to analyze how the characteristics of polar lows and their impact on the ocean vary with increased horizontal resolution of an atmospheric model. In particular, Marta will use the Regional Arctic System Model (RASM), which is a limited-area, fully coupled ice-ocean-atmosphere-land model. This study will provide evidence on the minimum atmospheric resolution required to represent the impact of PLs on the ocean circulation.
Understanding hydrogeomorphic impacts of rainstorm variability on dryland catchments
The erosion of the Earth’s surface caused by individual rainstorms is one of the most progressive climatic impacts on worldwide landscapes. Especially in climate-sensitive drylands, changes in rainstorms properties, as a consequence of climatic changes, affect erosion rates and patterns that could threaten societies' sustainability. However, evaluations of rainstorm erosion impacts are restricted by short and patchy rainfall records and a lack of erosion models to capture rapid topographic changes during infrequent extreme events. Yuval will work with Greg Tucker and Matthew Rossi on the erosional expression of climate change in drylands as driven by changes in rainstorm properties, utilizing new approaches for rainfall statistical analysis, recently-available climate records, and advances in erosion modeling tools. Through numerical experiments of runoff, erosion, and landscape evolution, the research aims to translate climate change projections to erosion risks and to test hypotheses regarding past topographic changes triggered by rainstorm variability.
Using Reanalysis and MOSAiC’s Field Campaign to Explore the Role of Arctic Cyclone on Arctic Atmospheric Rivers and Their Associated Sea Ice Effects
Atmospheric rivers (AR) are one conspicuous pathway for poleward moisture transport from lower latitudes. They have been known to influence Arctic warming and sea ice decline in the boreal winter. Likewise, cyclones play an important role in the Arctic climate: Arctic cyclones strongly interact with the diminishing sea ice. While over the Arctic, the dynamic and physical process of how Arctic cyclones influence ARs and the associated sea ice effects are still missing in the literature. Thus, Chen Zhang will work with Profs. John Cassano, Mark Serreze, and Matthew Shupe use reanalysis and MOSAiC data to provide a comprehensive dynamic/thermodynamic analysis to quantify the influence of Arctic cyclones’ dominant physical factors on ARs and the associated sea ice evolution via the subsequent surface radiative budgets. Such physical understanding will lead to improved cyclone and AR predictions in the changing climate and bridge a knowledge gap in Arctic amplification.
