Browsing by Subject "Climate"

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Characteristics of principal leadership influencing school culture.
(2012-05) Hudson, Norma J.
The primary purpose of this study is to examine characteristics of principal leadership influencing school culture as viewed by stakeholders involved in the International Schools Group (ISG) in Saudi Arabia. A secondary purpose of this study is to inform ISG educational leaders about the perspectives of their respective stakeholder groups regarding principal leadership characteristics and school culture. Four research questions guided this study. The research questions focused on the characteristics of principal leadership that influence school culture as viewed by ISG parents, support staff, teachers, administrators, and Board of Trustees members. Other questions were analyzed according to perspectives from each division within ISG: the American Division, the British Division, and the International Division; gender; and Western and non-Western nationalities. A mixed methods study was conducted for this research. The design included an electronic survey, focus groups, and individual interviews, and data were gathered through qualitative and quantitative methods. Using a concurrent triangulation strategy, quantitative data were analyzed using SPSS v. 18. Descriptive statistics were used for research question 1, an ANOVA for research question 2, and t-tests for research questions 3 and 4. Qualitative data was analyzed by comparing and contrasting the results from the focus groups and individual interviews to determine similarities and differences. Using a one-way factorial ANOVA, the results indicate that there are statistically significant differences in seven leadership characteristics as viewed by the American Division, the International Division, and the British Division. An independent sample 2-way t-test was conducted to determine if there were any statistically significant differences in gender perspectives or Western and non-Western perspectives. Five leadership characteristics were statistically significant according to gender, while the findings indicate that there were 14 characteristics that were statistically significant between Western and non-Western participants. Qualitatively, focus groups and individual interviews resulted in identifying two primary leadership characteristics that influence school culture: being an effective communicator and being ethical while demonstrating integrity. It is hoped that this dissertation will help ISG leaders and other educational professionals understand the role that leaders play in impacting school culture.
Climate of Minnesota Part VII - Areal Distribution and Probabilities of Precipitation in the Minneapolis-St. Paul Metropolitan Area
(Minnesota Agricultural Experiment Station, 1973) Baker, Donald G.; Kuehnast, Earl L.
Ecology, conservation and climate-fire challenges on Uluguru Mountain biodiversity hotspot, Tanzania
(2010-12) William, Christopher Mungo Peter
In this research, I investigate the relationship between short-term climate variability and the fire ecology of the Uluguru Nature Forest Reserve (UNFR). I investigate the influence of relief, altitude, the Indian Ocean Dipole or Dipole Mode Index (DMI), and Niño 3.4 on short (November-December) and long rains (March, April, May) in the UNFR. Fire events correlate weakly with amount of annual local rainfall, suggesting that fire occurrence in the UNFR results from a combination of factors, such as rainfall anomalies, topography, type of vegetation (fuel), timing and use of fire by local people as a farm preparation tool, and teleconnections. A thorough understanding of fire behavior across time and space is necessary to design a successful UNFR management plan; the resulting plan must address both anthropogenic and climatic drivers of fire.
Exploring Relationships among Organizational Factors, Teachers’ Attitudes toward Evidence-Based Practices, and Implementation of Universal Prevention Programs
(2019-12) Zhang, Yanchen
Decades of research have produced a wide range of evidence-based programs and practices (EBPs) for use in schools. However, the existence of EBPs alone is insufficient to produce changes in student outcomes, as promoting positive student outcomes depends on successful implementation. Research has identified numerous factors that either enable or obstruct the successful implementation of EBPs, including outer context (e.g., policy), inner context (e.g., leadership and climate), and innovation-specific (e.g., the complexity of an intervention) factors. Despite the influence of these factors, successful implementation ultimately resides with the decisions and behaviors of individual implementers (e.g., teachers). Attitudes toward EBPs have garnered significant attention across service sectors as an important factor that is linked to successful implementation. However, there is limited research that has examined the relationship among individual-level factors, such as attitudes toward EBPs, and school organizational factors, such as leadership and climate. Moreover, there is emerging findings highlighting the importance of assessing both general and implementation-specific organizational characteristics and how they interact to explain important implementation-relevant variables and outcomes. In light of these existing voids in the literature, the purpose of this study was to examine teachers' attitudes toward EBP in relation to general and implementation-specific leadership and climate hypothesized to influence the uptake and implementation of EBPs by teachers in school settings.
Fish abundance training data in support of: Climate-driven declines in abundance across thermal guilds in fish communities of 11,000 temperate lakes
(2025-01-13) Link, Denver J; Verhoeven, Michael R; Masui, Holly K; Nelson, Jenna KR; Hansen, Gretchen JA; ghansen@umn.edu; Hansen, Gretchen; University of Minnesota Department of Fisheries, Wildlife, Conservation Biology
Anticipating and planning for changes in biological communities due to climate warming presents numerous challenges, particularly in projecting how species abundance relationships will respond to future thermal conditions. In this study, we use regional fisheries-independent catch data to train a novel physiologically guided model that predicts fish abundances under warming scenarios in over 11,000 lakes across the Midwestern U.S. The dataset includes catch-per-effort data for eight sport fish species (cisco, northern pike, walleye, black crappie, yellow perch, smallmouth bass, largemouth bass, and bluegill sunfish) from 6,805 lakes, 46,287 surveys, and spanning 81 years (1940–2023) across seven states. We selected survey gear types for each state and species based on agency recommendations and survey documentation to ensure accurate representation of relative abundance. Rigorous data screening was performed to eliminate anomalies that could bias abundance estimates. Each survey location is linked to National Hydrography Dataset (NHD) identifiers, enabling integration with landscape-level environmental covariates. These data were used in a companion study to inform a joint species physiologically guided abundance model to project future species abundances across the region.
Generalizations for Insolation and Albedo to Adapt an Energy Balance Model to Other Planets
(2019-05) Nadeau, Alice
Interest in modeling the climates of other planets has been stimulated by observations of the Pluto-Charon system and seven Earth-sized planets orbiting the nearby star TRAPPIST-1. Furthermore, as of March 2019, over four thousand planets outside of our solar system have been discovered. Scientists are interested in what these planets might be like and if they could support life as we know it, but there is very little empirical information that they can collect in order to learn more about them. For this reason, scientists must rely on models to study climate on these planets. Because so little is known about our planetary neighbors compared to Earth, and even less is known about planets outside of our solar system, it is hard to faithfully model their climates using complex models such as such as the class of models referred to as General Circulation Models (GCMs). Instead, conceptual climate models may be preferred because the small number of state variables and parameters (relative to GCMs) make it easier to quantify possible behaviors of the system. Adapting well known conceptual models for Earth to extraterrestrial and extrasolar planets raises issues whose solutions draw from the fields of celestial mechanics, harmonic analysis and nonsmooth systems. This work focuses on a main component of conceptual climate models---incoming radiation absorbed by the planet---and the mathematical considerations for and implications of adapting this component to planets other than Earth. We generalize both the distribution of insolation and location of different albedos on the planet's surface. We find that the insolation distribution for slowly rotating planets approaches a rapid rotation distribution like the reciprocal of the rotation rate. Additionally, we show that it is possible to have stable, asymmetric configurations of ice in an energy balance model of Pluto.
Growth and stand dynamics of Red maple-dominated forests in the Upper Great Lakes Region, USA
(2015-02) Pszwaro, Justin Luke
Red maple (Acer rubrum L.) was historically a common but not abundant tree species in North American temperate forests. Over the last several decades it has increased in abundance on upland sites throughout its range and today is perhaps the single most abundant tree species in eastern North America. Climate change and associated impacts on forest dynamics are expected to increase red maple relative importance in the Upper Lake States and New England. However, red maple lacks commercial importance and has thus received little attention in growth studies and little is known of the dynamics of red maple-dominated stands. The objectives of this thesis were to 1) quantify the effects of stocking level and stand age on overall patterns of red maple stand productivity, 2) evaluate how these relationships vary across different geographic locations and climatic conditions, and 3) describe the composition dynamics of pure red maple-dominated forest stands.
Impact of Pandemic on Atmospheric Carbon
(2021-08) Mosesov, Eleonora
The COVID-19 pandemic has caused a decrease in carbon dioxide emissions. Here we will look at the atmospheric carbon dioxide, carbon-13, and carbon dioxide emissions data in order to determine whether the drop in emissions had an effecton atmospheric carbon dioxide and carbon-13. For carbon dioxide and carbon-13, we look at the trend and the seasonal pattern. To find whether 2020 is an outlier, we find the average values and compare them to previous years, as well as compare the monthly data. The data in 2020 for the atmospheric carbon dioxide and carbon-13 did not show a drop, and was not an outlier.
Neighborhood Voices: A Lincoln Park Climate and Water Impacts Survey
(2024-01) Carlson, Jessy R; Sowers, Maia A; Bliss, Morgan; Rodman, Madison G; Sprague, Tiffany A
In 2022, a survey of Lincoln Park neighborhood residents’ perspectives and observations was conducted in order to better understand community perspectives on solutions and challenges related to flooding in the neighborhood. The results of this survey suggest that respondents are concerned about increased flooding in their communities. Survey respondents reported that they feel it is the responsibility of the city and state to manage the problem, but also reported that they want more information about what they can do to mitigate the risk themselves. Additionally, they reported that they value existing green and blue spaces, and want more of them; they also stated that they feel it is important that these spaces serve to manage stormwater in addition to providing social benefits to community members. This document reports the results of that survey.
Restoration's return in the age of climate crisis: toward a feminist environmental justice response
(2014-11) Garvey, Michelle Jenneman
This project is situated at the locus of discourses on feminism, environmental justice, climate change, and ecological restoration. Asking what kinds of responses to climate change are needed on this rapidly-changing planet, and which initiatives will address social and ecological dilemmas simultaneously, I turn to ecological restoration as a troubled but promising field to harness the insights of feminist environmental justice toward intervening in both the causes and consequences of climate change. In order to engender resiliency among human and nonhuman communities, I advocate a contextualized, grassroots response to climate change that I have coined justice-oriented restoration. This ideology and method strengthens voices and movements often marginalized by engaging diverse stakeholders in order to create ecologies responsive to climatically-induced biosocial shifts, as well as the declining field of restoration itself, which climate change threatens to render irrelevant. In so doing, this project contributes to debates on sustainability; to the cross-pollination of the humanities, social sciences, and sciences; and to the momentum building worldwide for community-driven, site-specific adaptations, mitigations, and remediations to environmental vulnerabilities.
A three-dimensional model of Lake Superior with ice and biogeochemistry: investigating interannual Lake Trends and the deep chlorophyll maximum
(2013-12) White, Brooke
The development of a realistically configured three-dimensional model for Lake Superior including prognostic ice and biogeochemistry models is documented. The addition of a prognostic ice model is a significant advance over previous modeling efforts. The hydrodynamic, ice and biogeochemical models are described and behavior of the model during the period 1985 to 2008 and focusing on the annual cycle of 2005 is discussed. The model is found to sufficiently reproduce many observed physical and biological characteristics of Lake Superior. It is also successfully applied in two scientific investigations: interannual trends in lake temperature, ice cover and primary productivity and elucidation of the causal mechanisms of Lake Superior's deep chlorophyll maximum. The formation of winter ice on Lake Superior has been shown to be important in determining the annual thermal cycle of the lake and long-term trends of surface water temperature increase. However, modeling studies of Lake Superior to date have not included dynamic and thermodynamic ice cover. These physical characteristics of the lake in turn can have significant impacts on biogeochemical cycling within the lake. Modeled long-term interannual trends in increasing water temperature and decreasing ice cover are compared with observed rates. In the model, total annual gross primary productivity is found to correlate positively with mean annual temperature and negatively with mean winter ice cover magnitude.The deep chlorophyll maximum (DCM) is a near ubiquitous feature in Lake Superior during the summer stratified season. Previous studies have elucidated observable characteristics of the DCM in Lake Superior but the physical and biological mechanisms controlling the creation and maintenance of the DCM remained unclear. Sensitivity runs are performed to explore the influence of photoadaptation, photoinhibition, zooplankton grazing, and phytoplankton sinking on the vertical distribution of chlorophyll in the water column. The role of a nutricline in determining the presence and nature of the DCM is also explored. The presence of the DCM is dependent upon the presence of thermal stratification in the model. The sensitivity runs reveal that photoadaptation plays a primary role in determining the depth of the DCM in the model while zooplankton grazing and phytoplankton sinking affected the magnitude but not the presence or depth of the DCM. Photoinhibition showed negligible effects on chlorophyll concentration distribution. The presence of a nutricline in the model is also a necessary condition for the formation of the DCM and it influences both the depth and magnitude of the DCM.
Topics on Climate Model Output Analyses
(2021-10) Gong, Kaibo
Comparison of two different data samples, and of paired data samples, is a well known problem in Statistics. Specifically, there is a wide range of applications in the fields of climate study. In this thesis, we provide a brief review on the ensemble of climate models and the need of probabilistic evaluation of model outputs, which is equivalent to the comparison between two models. Based on recent advancements in the context of evaluating climate model outputs, we develop two different approaches for comparing two functional time series. The first one is based on wavelet decomposition and the second one by comparing the local spectral density of non-stationary series. For the last chapter, we conduct a brief review on Gaussian Process and a framework for Bayesian Optimization, which establishes a theoretical framework and algorithmic properties of t-process based spatio-temporal modeling, for further use in modeling climate and neuroscience data.
Understanding the environmental controls on plant mercury from northern Minnesota peatlands.
(2024-12) Behrens, Kevin
Peatlands are delicate ecosystems that play a crucial role in global biogeochemical cycles, particularly in the storage and cycling of mercury (Hg). Human activities, especially since the Industrial Revolution, have dramatically increased Hg levels in the environment, raising concerns due to health risks associated with its bioaccumulation and biomagnification in food webs. The ability of peatlands to influence the fate, transport, and conversion of Hg is significant, as they are known to act as both sinks and potential sources of this toxic element. Additionally, climate change, which has accelerated due to human activity, further complicates the dynamics of Hg in ecosystems by altering key biogeochemical cycles. A deeper understanding of how climate change affects Hg concentration in peatlands is essential for predicting future environmental conditions and their impacts on human and ecological health. This study investigates THg (total mercury) concentration in peatland vegetation under various climate change scenarios, focusing on how warming, elevated carbon dioxide (eCO2), and peatland type influence Hg uptake by six common peatland species. The research was conducted at the USDA Forest Service Marcell Experimental Forest at the Department of Energy’s SPRUCE (Spruce and Peatland Responses Under Changing Environments) site, a unique climate change experiment designed to simulate future environmental conditions. Samples were collected from six bioindicator species bi-weekly over a 26-week period in 2021, spanning the entire growing season from spring to fall. The samples were then processed and analyzed at the University of Minnesota to quantify THg concentrations.Results from the study showed species-specific responses to warming and eCO2. Sphagnum moss, leatherleaf, and black spruce exhibited significant increases in THg concentrations under warming conditions, with a critical threshold observed at +4.5°C, beyond which THg concentration rates declined. Tamarack displayed a different response, showing decreasing THg concentration with increased temperatures alone, until +4.5°C where concentrations began to increase. The interaction between eCO2 and warming further complicated these dynamics, as eCO2 generally led to a reduction in mean THg concentrations for most species, except for tamarack, which accumulated more THg under these eCO2. The results highlight the complex relationship between plant physiology and climate variables and mercury concentrations in plants. Peatland type (bog vs. fen) did not significantly affect THg concentration for most species, except for Labrador tea, which accumulated more THg in fen environments. The study suggests that hydrology plays a secondary role in climate in THg cycling, but species like Labrador tea may be more sensitive to moisture and nutrient availability. Overall, the findings underscore the importance of species-specific responses and climate thresholds on THg concentration. The results provide a foundation for predicting how peatlands, and the broader ecosystems they support, may behave under future climate conditions. By understanding the role of temperature and CO2 in THg concentration, this study contributes valuable insights to the management of peatland ecosystems, which could inform strategies to mitigate THg pollution and its ecological and human health risks.
Wetlands of Cook Inlet Basin, Alaska: Classification and Contributions to Stream Flow
(2017-04) Gracz, Michael
Wetlands face threats from global change, even as protections have been institutionalized to conserve the amenities they provide. These institutional protections frequently rely on a wetland classification system to guide conservation. In the Cook Inlet Basin of Alaska, USA (CIB), for example, best wetland assessment practices require the use of a classification system to ensure the conservation of the most valuable amenities. However, the systems used widely in the USA outside of Alaska, where peatlands are not common, inadequately describe the diversity of peatlands on the glaciated landscape of the CIB. Here I present a new Cook Inlet Classification system (CIC) organized around the hydrogeologic settings of wetlands in the CIB. The variables most strongly correlated with ecological differences within major geomorphic classes were used to construct a system supported by ample field data. The CIC produced greater within-class similarity than other widely-used systems, likely due to the overriding importance of the seasonal variability of water levels in CIB peatlands. The CIC has been mapped over an area of 7600 km2 and has guided wetland functional assessments in the CIB, and may be adaptable to any region supporting peatlands on glacial landforms. The harmful effects of a warming climate on aquatic resources may be partially ameliorated by discharge of shallow groundwater from peatlands to streams. This potential benefit of peatlands was investigated in the CIB using end-member mixing analysis (EMMA) and a sensitivity analysis of a water budget to quantify the contribution from extensive peatlands formed over glacial lake deposits to stream flow during the dry-season. Although peatlands in this hydrogeologic setting are common globally, the discharge from them is challenging to quantify. A spatially distributed sampling protocol at a single point-in-time produced a reliable EMMA showing that over half of stream flow on a day during the summer dry period originated near the surface of peatlands. This finding is being used to establish the value of peatlands for buffering increases in stream temperature, which have exceeded tolerances of commercially important fishes in the CIB. The analysis also suggests that differences in hydrogeologic setting influence shallow groundwater hydrology in peatlands.
What do trees remember? Disentangling climate, biological, and ecological signals from tree-ring time series
(2022-10) McPartland, Mara
Dendrochronology, the study of tree rings, uses variation in the annual growth patterns of trees to make inferences about the past. Most commonly used as records of past climate, tree ring analysis has built our understanding of how the climate has varied during the Common Era. Tree rings are also physical records of tree growth, and are often used in ecosystem science to understand how climate and environment influence the health of forests. In order to use tree rings to infer past changes in environment and ecosystems, researchers must content with the complexity of exogenous (climatic and environmental) and endogenous (biological) signals contained within annual tree rings. A range of statistical and data processing techniques are used to filter tree-ring time series to extract specific signals and discard unwanted sources of variance, but these techniques are imperfect and may result in biased estimates of the relationship between climate and tree growth through time. In my dissertation, I evaluate how assumptions made about the sources of variance contained within tree rings, as well as choices made during data development and analysis, influence the outcome of tree-ring studies. I explore these themes through three separate case studies, described in four chapters. In my first chapter, I compared different data processing methods commonly used by dendrochronologists to determine their effects on final chronologies. In my second and third chapters, I investigate the relationship between drought and radial growth patterns, and explore whether drought should be thought of following a classic ‘disturbance’ model, or as an ongoing climatic phenomenon. In my final chapter, I analyzed whether evidence of anthropogenic warming is visible in tree-ring series from Minnesota – a region where trees are not typically considered sensitive to variations in climate.

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