Physical Sciences and Mathematics Commons^™

Forest Fire Effects On The Temporal Variability Of Landscape Snow Albedo Relative To Burn Severity, Max Gersh

Dissertations and Theses

Snow-water storage is decreasing, while forest fires are increasing in duration, size, frequency, and intensity, due to climate change. Most forest fires occur in the seasonal snow zone, altering snow mass and energy balance for many years following fire. Following forest fires, Surface snow albedo (SSA) decreases, as light absorbing particles (LAP), particularly black carbon (BC) produced in forest fires get deposited throughout the snowpack, altering snowpack energy balance driving earlier snowmelt in burned forests. While SSA decreases, landscape snow albedo (LSA) increases following fire, as more of the snow-covered surface becomes visible beneath the burned forest canopy, brightening the …

Climate Model Evaluation Of Atmospheric Rivers Over The Contiguous United States, Ilan González-Hirshfeld

Dissertations and Theses

Atmospheric rivers (ARs)--long corridors of intense atmospheric water vapor transport--significantly influence the hydrologic cycle and regional hydrometeorological extremes across the contiguous United States (CONUS). Ongoing and future climate change may alter AR characteristics and impacts, making confident climate model projections of future change, especially at regional scales, of critical importance. In order to better constrain uncertainty in such projections of future change, we perform a comprehensive climate model evaluation of AR climatology over the CONUS. Using an established AR detection algorithm, we evaluate the representation of ARs in historical simulations (1984-2013) from a suite of models participating in the sixth …

Projections Of Large-Scale Atmospheric Circulation Patterns And Associated Temperature And Precipitation Over The Pacific Northwest Using Cmip6 Models, Graham Patrick Taylor

Dissertations and Theses

Projections of 500 hPa geopotential height (Z500) patterns over the Pacific Northwest of North America and their associated surface temperature, precipitation, and frequency of occurrence are assessed using models from the 6th phase of the Coupled Model Intercomparison Project (CMIP6). The self-organizing maps approach is applied to reanalysis data from the Modern-Era Retrospective Analysis for Research and Applications, version-2 (MERRA-2) to cluster daily Z500 anomalies into 12 representative patterns that span the range of historical circulation patterns. CMIP6 data for daily Z500 anomalies are mapped to each node for historical and end of century global warming experiments, and the resulting …

A Ground-Based Assessment Framework For Validating Diesel Particulate Emission Models And Applicability In Portland, Or, Kirsten Marie Sarle

Dissertations and Theses

Exposure to diesel emissions causes a range of health effects throughout the body, impairing; respiratory, cardiovascular, central nervous, renal, and cognitive systems. Diesel particulate matter (DPM) in Portland, Oregon is prevalent due to the layout of highly trafficked roadways, rail lines, and marine ports exposing a dense population to high levels of exhaust pollution. These high concentrations of ambient diesel emissions disproportionately impact minority and low-income populations.

Ground-based monitoring and modeling are two ways to assess ambient DPM. However, there are uncertainties in modeled DPM due to knowledge gaps in emissions inventories as well as lack of model validation against …

Rowing Concerns: Collaborative Governance And Stakeholder Determination In The Central Oregon's Deschutes Basin, Noel Vineyard

Dissertations and Theses

In 2019, a coalition of irrigation districts in central Oregon's Deschutes Basin submitted the Deschutes Basin Habitat Conservation Plan to the US Department of Fish and Wildlife. This Habitat Conservation Plan purported to have been constructed through a collaborative governance structure between the irrigation districts and various community stakeholders who all had interests in basin management, however segments of the Basin's river recreation community began to raise concerns that their voices were not included. The purpose of this research was to investigate how stakeholder status in the Deschutes Basin is created through collaborative water governance processes like development of the …

A Community Of Fear: Emotion And The Hydro-Social Cycle In East Porterville, Michael Egge

Geography Masters Research Papers

Broader governance challenges driving water insecurity globally are well documented in the literature, however the power-laden relationships and emotions that shape water access at the household and community levels are yet to be fully investigated, especially in the context of water consolidation projects. In this article, we examine the role of emotions in mediating access to water and in the production of resource struggles among marginalized communities existing outside of conventional regulatory frameworks. We bring together two relational approaches – the hydro-social cycle and emotional political ecology – to examine water insecurity and how it manifests in the historically disadvantaged …

Influence Of Climate Change On Forest Fire Occurrence And Distribution Of Sri Lanka And Modeling Of Forest Fire, Mohan Heenatigala

Environmental Science and Management Professional Master's Project Reports

Forest fire is one of the main causes for forest degradation and deforestation which affect ecosystem services provided by the given landscapes. Weather variables like temperature, wind speed and direction, rainfall, and relative humidity also govern the forest fire regime and vulnerability. On the other hand, forest fuel characteristics, human impacts, population density, forest canopy density, slope, elevation, road density, closeness to the human settlement areas are other factors that determine the forest fire impact and potential of damage. Annually, 100 to 2500 hectares of forest resources are damaged due to forest fires in Sri Lanka. From the past few …

Understory Species Increase Project: Investigating The Revegetation Of Native Herbaceous Species From Seed In Urban Forest Fragments, Erin Mcelroy

Environmental Science and Management Professional Master's Project Reports

Management of urban forest fragments often aims to reduce invasive species and promote native species abundance and diversity. Often, these environments lack natural establishment of native forest species, including herbaceous species that are especially sensitive to site conditions. While herbaceous understory species may represent a small proportion of forest biomass, they perform important functions within forest environments, including nutrient cycling, erosion and runoff control, and providing habitat for wildlife, as well as hosting the greatest biodiversity among other forest strata. However, many restoration projects focus primarily on the revegetation of dominant woody forest species, such as hardwood trees and shrubs. …

Current Stormwater Practices And Future Implementation At Portland State University With The Uncertainty Of Climate Change, Evan Suemori, Alexandra Vargas Quiñones

Environmental Science and Management Professional Master's Project Reports

Stormwater runoff is one of the most critical environmental issues in urban areas and is only expected to worsen as climate change persists (EPA, 2016). When precipitation events occur, stormwater travels across impervious surfaces collecting soils and pollutants which can negatively impact water quality in receiving waters. Additionally, stormwater has human health impacts, specifically through flooding and the contamination of drinking water. According to the Intergovernmental Panel on Climate Change (IPCC), it has been determined that climate change will increase the frequency, intensity, and/or number of precipitation events in some regions, including the Pacific Northwest, and decrease in others (IPCC, …

Agency, Sense Of Place, And Knowledge On The Zumwalt Prairie: A Social Study Of Place-Based Conservation And Resilience, Dana Elyse Hellman

Dissertations and Theses

Shifting and often diminishing environmental conditions, due to climate change, resource loss, and ecosystem degradation, pose a significant concern to both social and ecological systems. The field of conservation science has attempted to address environmental threats through varying approaches, transitioning from fortress conservation and complete human exclusion to community-based and co-managed models which incorporate human actors and social dimensions in the conservation process. The latest iteration of conservation scholarship, place-based conservation, is deeply rooted in interdisciplinary, social scientific thinking, and calls for significant practitioner engagement with local knowledge, practices, social constructions, and place meanings. It is an approach which emphasizes …

Urban Lakes: Ecosystem Services And Management, Laura Costadone

Dissertations and Theses

Lakes provide a variety of ecosystem services and benefits that greatly contribute to urban sustainability. Despite the growing interest in integrating freshwater systems into management and policy decisions, urban lakes are often overlooked in land-use planning. Nutrient and pollutant runoff from the surrounding urbanized watershed result in water quality deterioration that negatively impact the lake ecological functions and related ecosystem services. The vulnerability and degradation of these urban ecosystems should be a matter of concern, especially considering that, in rapidly growing metropolitan areas, the demand for aesthetic and recreational services provided by urban lakes is increasing. The overall goal of …

Climatic Controls On The Kinematics Of The Hooskanaden Landslide, Curry County, Oregon, Kara Kingen

Dissertations and Theses

Slow-moving earthflows represent major sources of sediment transport and erosion and are problematic for the management of critical infrastructure. The Hooskanaden Landslide -- a slow-moving earthflow on the southwest coast of Oregon -- crosses US Highway 101 and has been a site of continued interest to the Oregon Department of Transportation (ODOT) due to the weak lithology, erosive environment, and recurrent surge behavior (every ~15 years). Past surges, including the most recent (2019), have occurred during the winter, suggesting that velocity changes are predominantly controlled by climatic inputs. To examine the response of the Hooskanaden Landslide to seasonal and other …

Posterior Predictive Critique Of A Psychometric Bayesian Model For Assessing Aphasia, Ashlynn Crisp

Mathematics and Statistics Dissertations, Theses, and Final Project Papers

For persons with aphasia, naming tests are useful for assessing the severity of the disease and observing progress toward recovery. The Philadelphia Naming Test (PNT) is a leading naming test composed of 175 items. The items are common nouns which are one to four syllables in length and with low, medium, and high frequency. Since the target word is known to the administrator, the response from the patient can be classified as correct or an error. If the patient commits an error, the PNT provides procedures for classifying the type of error in the response. Item response theory can be …

Evaluation Of Manual And Semi-Automated Deep-Seated Landslide Inventory Processes: Willapa Hills, Washington, Tiffany E. Justice

Dissertations and Theses

Recent advances in remote sensing data and technology have allowed for computational models to be designed that successfully extract landforms from the landscape. The goal of this work is to create one such semi-automated model to extract deep-seated landslides located in complex geomorphic terrain. This is accomplished using geographic object-based image analysis (GEOBIA) techniques, considered by leaders in the field of image analysis to have an advantage over traditional automated classification methods. GEOBIA methods can mimic human visual interpretation by including more characteristic features used to assess the relationship between image data and the ground surface such as color reflectance …