Cooperative Institute for Research in Environmental Sciences

Current Visiting Fellows

Current Visiting Fellows

Sebastian Chevrot



Imaging the deep architecture of continental orogens by full waveform inversion of teleseismic body waves - The Bighorn Mountains

Sebastien Chevrot is a CNRS senior scientist working at the Observatoire Midi Pyrenees in Toulouse, France. He is visiting CIRES this summer to work with Anne Sheehan, Vera Schulte-Pelkum, and others to study the deep architecture of the Bighorn Mountains and Tibetan Plateau. Detailed images of the deep architecture of continental orogens, in particular of their density structure, is crucial to unravel the relative importance of tectonics and climate change for the long term evolution of mountain ranges. However, the deep roots of continental orogens remain largely elusive, owing to the limited spatial resolution of conventional tomographic imaging techniques. Chevrot will be using his newly developed full waveform inversion methods to revisit the data from the Bighorn and Hi-Climb temporary experiments, to obtain high resolution images of lithospheric structures beneath the Bighorn Mountains and Tibetan Plateau. These images will be a valuable source of information to understand the structure and formation of continental orogens, and the long term support of high reliefs.

Justin Farrell



Using Computational Social Science to Examine Influences on Climate Policy

Justin Farrell is working with Max Boykoff, and others at CIRES, to expand his computational social science approach for understanding how climate change has become such a polarized issue in the United States. Continuing to blend network science with large-scale machine learning text analysis, Farrell will focus on expanding his methodological framework for improving our understanding about how the communication of science is produced and disseminated within connected networks and subnetworks of organizations. CIRES is an ideal institutional home for this sort of interdisciplinary and collaborative research program on cultural and political conflict over climate change. As a native of Cheyenne, Wyoming, Farrell is excited about returning to the region, but is especially excited about the opportunities for exchanging ideas with affiliates who may not work in quantitative social science, but bring a different and unique perspective that will be mutually beneficial.

Jennifer Henderson



Identifying the Dynamics of Vulnerability in Community Water Usage along the Front Range

Jen Henderson will work with CIRES Fellow Lisa Dilling, Director of the Western Water Assessment, and Rebecca Morss and Olga Wilhemi, of NCAR, to understand the complex nature of water-related vulnerabilities that arise in communities preparing for climate change and climate variability. She will study these dynamics of vulnerability through a qualitative, empirical analysis of current and future water use and management practices for two mid-size cities in Colorado. Henderson hypothesizes that this work will reveal how adaptations made to water use strategies in one place within the system may have unintended, and perhaps unseen, consequences at another point in the system. Research questions at the heart of this project ask the following: What does vulnerability mean for different stakeholder and lay publics? How is the term vulnerability itself taken for granted in ways that exclude specific demographics or problems? How do these vulnerabilities shift and migrate, or spill over to different sectors, as communities adopt mitigation strategies and build adaptive capacities for climate variability? By looking at different stressors these communities experience, she hopes to make visible groups that have become more vulnerable to water issues and reveal common problems that transcend the situatedness of a particular issue and relevant dissimilarities that result in vulnerabilities of different types and scope. Henderson is looking forward to working with scholars in Boulder and communities across the Front Range to advance an understanding of local climate related impacts and offer decision makers a valuable analysis of emerging vulnerabilities.

Uwe Karst



Aerosols meet Imaging Mass Spectrometry

Uwe Karst received his PhD in 1993 at the University of Münster, Germany in the group of Karl Cammann and moved to the University of Colorado in Boulder for a postdoctoral fellowship with Robert E. Sievers. After finishing his Habilitation in Münster, he was appointed as Full Professor of Chemical Analysis at the University of Twente, The Netherlands. In 2005, he took over his current position as Chair of Analytical Chemistry in Münster. His research main interests include hyphenated techniques, with particular focus on pharmaceutical analysis, elemental speciation and metallomics. In his project at CIRES, two different combined aspects of aerosols and imaging mass spectrometry will be investigated. One part of the project deals, in cooperation with Jose-Luis Jimenez, with the development of a novel combination of laser ablation (LA) and aerosol mass spectrometer for improved limits of detection in tissue imaging. Samples of rat lungs will be investigated. The interface of the aerosol mass spectrometer and the experimental conditions will be adapted to the flow rate coming from the LA under consideration of the fact that for imaging analysis, transient signals are obtained. In the second part of the project, in cooperation with Bob Sievers, an analytical method that allows monitoring the distribution of low molecular weight pharmaceuticals in tissues after supercritical fluid-assisted drug delivery will be developed. First, dry particles of the pharmaceuticals of interest will be generated using supercritical fluid-assisted nebulization. Antibiotics are a particularly interesting class of compounds and will be the substances of choice. Uwe is excited to return to CIRES after more than 20 years and looks forward to (re)establish interdisciplinary cooperations with colleagues from various research areas.

Elizabeth Maroon



How does the Atlantic Meridional Overturning Circulation influence the pace of anthropogenic surface warming?

Elizabeth Maroon will work with Jennifer Kay, Kristopher Karnauskas, and others at CIRES to study how the Atlantic Meridional Overturning Circulation (AMOC) interacts with the atmosphere to set the pace of global warming. Much of the excess heat trapped by greenhouse gases is absorbed by the ocean, which slows the rate of surface warming. As a result, the ocean plays an important role in setting how fast the surface warms. To improve our climate projections, we must have a full understanding of how the atmosphere and ocean interact to influence the rate of ocean heat uptake. The AMOC is a key component of the ocean circulation. While climate models show that the AMOC slows with greenhouse warming, how the AMOC influences ocean heat uptake is not well understood. Elizabeth will study how the AMOC’s strength, heat transport, and circulation vary in coupled ocean-atmosphere climate models. Because the AMOC can influence both tropical and extratropical climate through its heat transport, the interaction of regional atmospheric climate feedbacks with the AMOC will also be examined. Elizabeth completed her PhD at the University of Washington and is excited to join the research community at CIRES, especially because it was an undergraduate internship with CIRES scientists that started her career.

Amanda Maycock



Tropical tropopause layer processes and their coupling to climate

Amanda Maycock is working with Karen Rosenlof, David Fahey, Judith Perlwitz, Jennifer Kay, and others at the NOAA Earth System Research Laboratory to study the representation of the tropical tropopause layer (TTL) in global chemistry-climate models. The TTL is a region of the atmosphere between 14-18 km in the tropics that is distinguished by a combination of chemical, dynamical, physical and radiative characteristics from the troposphere below and the stratosphere above. Most air that is transported from the troposphere to the stratosphere passes through the TTL – the so-called ‘gateway’ to the stratosphere - and it is thus of central importance in the global chemistry-climate system. However, state-of-the-art global models show little convergence in representing TTL characteristics in the current climate, and exhibit large differences in the predicted response of the TTL to future changes in greenhouse gases. This source of uncertainty limits our ability to make accurate predictions of major environmental changes anticipated this century, such as ozone recovery and climate change. During her visit, Amanda will work with researchers to analyse key processes in current global models that may contribute to this uncertainty, and evaluate them against new observational datasets. The goal is for this to provide valuable new insights for developers and users of chemistry-climate models. After several short visits to Boulder in the past few years, Amanda is looking forward to an extended stay and having the opportunity to interact with the lively research communities at NOAA and CU.

Renee McVay



Aqueous-phase formation of secondary organic aerosol during wildfires: A modeling study

Renee McVay is collaborating with Joost de Gouw and members of the NOAA ESRL Chemical Sciences Division to model secondary organic aerosol (SOA) formation during wildfires with the regional model WRF-Chem. Biomass burning is the largest contributor to organic aerosol emissions globally, which have important climate and health consequences. Aerosols are either emitted directly (primary organic aerosols) or formed via gas-to-particle conversion during ageing of smoke plumes (SOA). The potential of wildfires to form SOA is still very uncertain. McVay will be working to update SOA formation in WRF-Chem by including non-traditional pathways to SOA, such as aqueous-phase reactions, that have heretofore been neglected but have the potential to form significant SOA. These updates will be constrained by environmental chamber experiments. Simulations using the updated WRF-Chem will be compared to field measurements of organic aerosols in wildfires as part of the Fire Influence on Regional and Global Environments Experiment (FIREX) campaign. This project will enhance understanding of SOA formation during wildfires and the dependence of this formation on chemical and meteorological conditions. This knowledge will enable better predictions of air quality, weather, and climate effects of wildfires. The updated WRF-Chem model will also be useful to fire managers and first responders for weather forecasting during wildfires.

Ivar van der Velde



Using atmosphere-biosphere data assimilation to improve terrestrial biosphere models and the North American carbon balance

Dr. Ivar van der Velde is a meteorologist with a keen interest in the land-atmosphere exchange processes of atmospheric trace gases. He is working together with Dr. John Miller and Dr. Stephen Montzka at NOAA Earth System Research Laboratory’s Global Monitoring Division to study the global terrestrial carbon dioxide sink with a focus on North America. This sink remains uncertain in a warming world where droughts may be more extreme and more frequent. The impact of droughts is likely to be net carbon release, potentially leading to more extreme drought conditions. These feedbacks between the terrestrial carbon cycle and climate are poorly understood and represent a first order uncertainty in climate prediction. It is therefore critical to improve the representation of the terrestrial biosphere in carbon-climate models. Ivar’s previous work at Wageningen University in the Netherlands indicated that the combined use of atmospheric CO2 and its isotopologue (δ13C) could potentially help to constrain the net carbon balance and underlaying exchange processes. In the current project he is focussing on the development of a data assimilation system that utilizes a novel combination of atmospheric CO2 and δ13C data to optimize well-known model parameters in terrestrial biosphere models. The main research goals are to improve our understanding of the large-scale moisture controls on carbon dioxide fluxes. This will be valuable for the plant-physiological research community and will help define where NOAA should measure CO2 and δ13C in the United States and around the globe in order to better understand the drivers of carbon exchange variability. In his spare time Ivar can be found exploring Colorado’s hiking trails and investigating the quality of Boulder’s brewery pubs.