Paleo-feedbacks in the hydrological and energy cycles in the Community Climate System Model 3

Department Head: Dick Johnson.2008 Summer.Includes bibliographical references (pages 68-73).This research focuses on the joint variability of the hydrological and energy cycles for the atmosphere and lower boundary and climate feedbacks associated with these changes at the Last Glacial Maximum. The LGM simulated climate experiences a global cooling of 4.9 K compared to the PI climate, with greatest cooling in the high latitudes of both hemispheres. Additional cooling also exists over the continental ice sheets in North America, Northern Europe, and Antarctica. Precipitation and evaporation are reduced by 10%, and precipitable water by 20%, compared to conditions at PI. Overall, from LGM to PI the changes in clouds are weak. The water vapor, ice-albedo, and cloud feedbacks act to amplify the climate change from LGM to PI. The positive water vapor and ice-albedo feedbacks account for 5.04 W m-2 K-1 and 2.38 W m-2 K-1, respectively of the climate change. The cloud feedbacks produces -2.83 of the change. An interesting and unexpected result was that the sign of the ice-albedo feedback changed regionally and is driven by changes in ocean basin size. Combined, the radiative feedbacks from LGM to PI act to amplify the climate change by 5.67 W m-2 K-1 and are balanced by an increase in surface evaporation

Interactions of arctic clouds, radiation, and sea ice in present-day and future climates

2016 Spring.Includes bibliographical references.The Arctic climate system involves complex interactions among the atmosphere, land surface, and the sea-ice-covered Arctic Ocean. Observed changes in the Arctic have emerged and projected climate trends are of significant concern. Surface warming over the last few decades is nearly double that of the entire Earth. Reduced sea-ice extent and volume, changes to ecosystems, and melting permafrost are some examples of noticeable changes in the region. This work is aimed at improving our understanding of how Arctic clouds interact with, and influence, the surface budget, how clouds influence the distribution of sea ice, and the role of downwelling longwave radiation (DLR) in climate change. In the first half of this study, we explore the roles of sea-ice thickness and downwelling longwave radiation in Arctic amplification. As the Arctic sea ice thins and ultimately disappears in a warming climate, its insulating power decreases. This causes the surface air temperature to approach the temperature of the relatively warm ocean water below the ice. The resulting increases in air temperature, water vapor and cloudiness lead to an increase in the surface downwelling longwave radiation, which enables a further thinning of the ice. This positive ice-insulation feedback operates mainly in the autumn and winter. A climate-change simulation with the Community Earth System Model shows that, averaged over the year, the increase in Arctic DLR is three times stronger than the increase in Arctic absorbed solar radiation at the surface. The warming of the surface air over the Arctic Ocean during fall and winter creates a strong thermal contrast with the colder surrounding continents. Sea-level pressure falls over the Arctic Ocean and the high-latitude circulation reorganizes into a shallow "winter monsoon." The resulting increase in surface wind speed promotes stronger surface evaporation and higher humidity over portions of the Arctic Ocean, thus reinforcing the ice-insulation feedback. In the second half of this study, we explore the effects of super-parameterization on the Arctic climate by evaluating a number of key atmospheric characteristics that strongly influence the regional and global climate. One aspect in particular that we examine is the occurrence of Arctic weather states. Observations show that during winter the Arctic exhibits two preferred and persistent states — a radiatively clear and an opaquely cloudy state. These distinct regimes are influenced by the phase of the clouds and affect the surface radiative fluxes. We explore the radiative and microphysical effects of these Arctic clouds and the influence on these regimes in two present-day climate simulations. We compare simulations performed with the Community Earth System Model, and its super-parameterized counterpart (SP-CESM). We find that the SP-CESM is able to better reproduce both of the preferred winter states, compared to CESM, and has an overall more realistic representation of the Arctic climate

ATS680A3 - Social Responsibility in Atmospheric Science pre/post evaluation survey tool

This survey was developed between staff and faculty of the CSU STEM Center and the Dept of Atmospheric Science for the use of evaluation of a course supported by NSF EAGER grant (NSF #2039480).September 2021.This is the survey tool used to evaluate the Fall 2021 cohort of Social Responsibility in Atmospheric Science course taught by Melissa Burt

Effect of air pollution and racism on ethnic differences in respiratory health among adolescents living in an urban environment

Recent studies suggest that stress can amplify the harm of air pollution. We examined whether experience of racism and exposure to particulate matter with an aerodynamic diameter of less than 2.5 µm and 10 µm (PM2.5 and PM10) had a synergistic influence on ethnic differences in asthma and lung function across adolescence. Analyses using multilevel models showed lower forced expiratory volume (FEV1), forced vital capacity (FVC) and lower rates of asthma among some ethnic minorities compared to Whites, but higher exposure to PM2.5, PM10 and racism. Racism appeared to amplify the relationship between asthma and air pollution for all ethnic groups, but did not explain ethnic differences in respiratory health

The convection connection: how ocean feedbacks affect tropical mean moisture and MJO propagation

The response of the Madden-Julian oscillation (MJO) to ocean feedbacks is studied with coupled and uncoupled simulations of four general circulation models (GCMs). Monthly mean SST from each coupled model is prescribed to its respective uncoupled simulation, to ensure identical SST mean state and low-frequency variability between simulation pairs. Consistent with previous studies, coupling improves each model's ability to propagation MJO convection beyond the Maritime Continent. Analysis of the MJO moist static energy budget reveals that improved MJO eastward propagation in all four coupled models arises from enhanced meridional advection of column water vapor (CWV). Despite the identical mean state SST in each coupled and uncoupled simulation pair, coupling increases mean-state CWV near the Equator, sharpening equatorial moisture gradients and enhancing meridional moisture advection and MJO propagation. CWV composites during MJO and non-MJO periods demonstrate that the MJO itself does not cause enhanced moisture gradients. Instead, analysis of low-level subgrid-scale moistening conditioned by rainfall rate (R) and SST anomaly reveals that coupling enhances low-level convective moistening for R > 5 mm/day; this enhancement is most prominent near the Equator. The low-level moistening process varies among the four models, which we interpret in terms of their ocean model configurations, cumulus parameterizations, and the sensitivity of convection to column relative humidity

Synthesis and Characterization of Silica-Supported Boron Oxide Catalysts for the Oxidative Dehydrogenation of Propane

In this contribution we report on the oxidative dehydrogenation (ODH) activity of silica-supported boron oxide prepared via incipient wetness impregnation. Characterization of pristine and spent catalysts with infrared, Raman, and solid-state NMR spectroscopy reveals the presence of both isolated and aggregated oxidized boron sites. The results of these investigations, in combination with our earlier work on bulk boron-containing ODH catalysts (e.g., h-BN, metal borides, and elemental boron), bolster the hypothesis that oxidized boron species in situ formed on the surface of these materials are responsible for the exceptional catalytic behavior. We anticipate that investigation of supported boron materials can provide insight into the structural characteristics required for selective boron-containing ODH catalysts

Dataset associated with "Seeking congruity for agentic women: a longitudinal examination of college women's persistence in STEM"

Those interested in using these data are encouraged to contact Dr. Paul Hernandez ([email protected]) and Dr. Emily Fischer ([email protected]) for more information. Data Contacts: Paul R. Hernandez (primary), [email protected], 979-464-9229 Emily V. Fischer, [email protected], 970-491-8587.Survey data were collected via the online Qualtrics survey system twice yearly in the fall and spring semesters from fall 2015 through spring 2019. This repository contains the data file associated with all surveys utilized in the analyses presented in this research article.Format of Data Files: Data files are in .csv format. Files can be opened by most software (e.g., Notepad, WordPad, Excel) – anything that can read a comma delimited ASCII text file. Here, the file name is "Dataset." In addition, a codebook accompanies the data file. The codebook contains the variable names, variable labels, and value labels for all variables contained within the "Dataset.csv" file.An abundance of literature has examined barriers to women's equal representation in science, technology, engineering, and math (STEM) fields, with many studies showing that STEM fields are not perceived to afford communal goals, a key component of women's interest in future careers. Using Goal Congruity Theory as a framework, we tested the longitudinal impact of perceptions of STEM career goal affordances, communal and agentic goals, and their congruity on persistence in science from the second through fourth years of college among women in STEM majors. We found that women's intent to persist in science were highest in fall of their second year, that persistence intentions exhibited a sharp decline, and that eventually leveled off by their fourth year of college. This pattern was moderated by perceptions of agentic affordances in STEM, such that women with higher perceptions of agentic affordances experienced smaller declines. Similar to prior research, we found that higher perceptions of communal goal affordances in STEM consistently predicted higher persistence intentions. Finally, we found an agentic goal-affordance congruity interaction, such that higher perceptions of agentic affordances in STEM predicted higher persistence intentions; however, the positive relationship was stronger for women with higher agentic goals. We conclude that because STEM fields are stereotyped as affording agentic goals, women who identify interest in a STEM major during their first year of college may be drawn to these fields for this reason, and may benefit from perceptions that STEM affords both communal and agentic goals.Funding for this work was provided by the National Science Foundation through grant number DUE- 1431795, DUE-1431823, and DUE-1460229

Probing the Transformation of Boron Nitride Catalysts under Oxidative Dehydrogenation Conditions

Hexagonal boron nitride (h-BN) and boron nitride nanotubes (BNNT) were recently reported as highly selective catalysts for the oxidative dehydrogenation (ODH) of alkanes to olefins in the gas phase. Previous studies revealed a substantial increase in surface oxygen content after exposure to ODH conditions (heating to ca. 500 °C under a flow of alkane and oxygen); however, the complexity of these materials has thus far precluded an in-depth understanding of the oxygenated surface species. In this contribution, we combine advanced NMR spectroscopy experiments with scanning electron microscopy and soft X-ray absorption spectroscopy to characterize the molecular structure of the oxygen functionalized phase that arises on h-BN and BNNT following catalytic testing for ODH of propane. The pristine BN materials are readily oxidized and hydrolyzed under ODH reaction conditions to yield a phase consisting of three-coordinate boron sites with variable numbers of hydroxyl and bridging oxide groups which is denoted B(OH)xO3–x (where x = 0–3). Evidence for this robust oxide phase revises previous literature hypotheses of hydroxylated BN edges as the active component on h-BN

The ethics of diversity, equity, inclusion, and justice in the earth system sciences

Institutions’ motivations for pursuing diversity, equity, inclusion and justice (DEIJ) often center on the benefits to the organization, an argument known as the business case for diversity in which diverse teams are more creative, set high bars for research, and produce ideas that are more innovative than those produced by homogeneous groups. As the sole motivation for DEIJ efforts, the business case is flawed and does not address the harmful workplaces many marginalized scholars encounter. Institutions can make more progress towards diversifying the STEM workforce by acknowledging the ethical responsibilities for doing so and transitioning to an equity-centered approach. Emphasizing personal motivations to actively engage in DEIJ work resonates with individuals more, rather than engaging with DEIJ to benefit an institution’s goals. Two recent studies support this argument. The first is an alumni survey and focus groups of postdoctoral fellows in the Advanced Studies Program at the National Center for Atmospheric Research to explore alumni efforts and motivations for engaging in DEIJ work. The second study surveyed attitudes towards DEIJ efforts among STEM graduate students at Colorado State University who took a course on social responsibility in science. Both studies show the motivations for scientists to support and get involved in these efforts and indicate that the business case is misaligned with the motivations of students and professionals in STEM. Understanding the attitudes and motivations that individuals have for DEIJ in STEM presents an opportunity for how institutions can best learn from and support these motivations for systemic change