Physical Sciences and Mathematics Commons^™

Using Biometrics, Behavioral Observations, And Multiple Molecular Techniques To Assess The Impacts Of Changes In Temperature And Salinity On The Common Bay Mussel (Mytilus Trossulus), Casey Martin

Dissertations and Theses

The intertidal zone is a place of rapid and frequent change that is home to a variety of creatures who are essential to the integrity of the habitat. Mussels are robust sessile bivalves that anchor to the rocks of the intertidal. The prominent species on the Oregon Coast, the Common Bay Mussel (Mytilus trossulus), plays an essential role as a coastal food source, water column filter, and barrier to prevent erosion due to wave action. Mytilus trossulus withstands daily shifts in temperature, salinity, and tide, as well as seasonal changes. Global climate change due to excess carbon emissions …

The Impact Of Climate Change On Selected Pnw Watersheds Through The Lens Of Western Red Cedar Habitat, Jordan T. Hamann

Dissertations and Theses

Climate change is a real phenomenon that is exacerbating existing natural processes and developing into a new normal for the planet. This change may be devastating for Pacific Northwest populations of Western Red Cedar (WRC) west of the Cascade Mountain range in the states of Oregon and Washington. WRC is a valuable tree species for reasons both economic and cultural. Dieback among WRC is following an accelerating trend. Since dieback is usually followed by tree mortality, understanding its causes and distribution is beneficial to the overall success of the species going into the future.

Through the use of ESRI's ArcGIS …

Short Warm-Side Wet-Bulb Temperature Distribution Tails Lead To Accelerated Increases In Extreme Threshold Exceedances Under Global Warming, Yianna Sotirios Bekris

Dissertations and Theses

Humid-heat extremes threaten human health and are increasing in frequency with global warming, so elucidating factors affecting their rate of change is critical. This thesis examines the role of historical (1985-2014) wet-bulb temperature distribution tail shape on the probability of wet-bulb temperature extreme threshold exceedances under 2°Celsius global warming. Analysis of global climate models and reanalysis reveals that non-Gaussian wet-bulb temperature distribution tails are common worldwide across extensive, spatially coherent regions. More rapid increases in the number of days exceeding the historical 95th percentile are projected in locations with shorter-than-Gaussian warm-side tails. Of the two primary components of wet-bulb temperature, …

Sea Surface Temperatures And Vertical Wind Shear As Precursors To Tropical Cyclone Activity In The Caribbean And An Expanding Main Developing Region, Keneshia Hibbert

Dissertations and Theses

Sea surface temperatures and vertical wind shear are essential to tropical cyclone formation. TCs need warm SSTs and low shear for genesis. Increasing SSTs and VWS changes influence storm development. This work analyzes SST and VWS trends for the Caribbean, surrounding region, and the Atlantic hurricane main developing region from 1982 to 2020. Storm intensity increases significantly during this period. Annual and seasonal trends show regional SSTs in the MDR are warming annually (0.0219°C yr^-1) and per season (0.0280°C yr^-1). Simultaneously, VWS decreases during the late rainfall season at 0.0556m/s yr^-1 in the MDR and …

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 …

An Overview And Evaluation Of Synthetc: A Statistical Model For Extra-Tropical Cyclones, Rafael Uryayev

Dissertations and Theses

Extratropical cyclones (ETCs) are the most common weather phenomena affecting the United States, Canada, and Europe. They can pose serious hazards over large swaths of area. In this thesis, a statistical model of ETCs, called SynthETC, is discussed. The model accounts for the for genesis, track path, termination, and intensity of statistically generated ETCs. Genesis is modeled as a Poisson process, whose mean is determined by climate and historical information. Tracks are modeled as a regression-mean determined by climate and historical information plus a stochastic component. Lysis is modeled using logistic regression, with climate states as covariates. Intensity is modeled …

Hydroclimate Drivers And Atmospheric Dynamics Of Floods, Nasser Najibi

Dissertations and Theses

Our preliminary survey showed that most of the recent flood-related studies did not formally explain the physical mechanisms of long-duration and large-peak flood events that can evoke substantial damages to properties and infrastructure systems. These studies also fell short of fully assessing the interactions of coupled ocean-atmosphere and land dynamics which are capable of forcing substantial changes to the flood attributes by governing the exceeding surface flow regimes and moisture source-sink relationships at the spatiotemporal scales important for risk management. This dissertation advances the understanding of the variability in flood duration, peak, volume, and timing at the regional to the …

Multi-Dimensional Drought Risk Assessment Based On Socio-Economic Vulnerabilities And Hydro-Climatological Factors, Ali Ahmadalipour

Dissertations and Theses

Drought is among the costliest natural hazards developing slowly and affecting large areas, which imposes severe consequences on society and economy. Anthropogenic climate change is expected to exacerbate drought in various regions of the globe, making its associated socioeconomic impacts more severe. Such impacts are of higher concern in Africa, which is mainly characterized by arid climate and lacking infrastructure as well as social development. Furthermore, the continent is expected to experience vast population growth, which will make it more vulnerable to the adverse effects of drought. This study provides the first comprehensive multi-dimensional assessment of drought risk across the …

Watershed Response To Climate Change And Fire-Burns In The Upper Umatilla River Basin Using The Precipitation Runoff Modeling System, Kimberly Crystal Yazzie

Dissertations and Theses

This study provides an analysis of watershed response to climate change and forest fire impacts, to better understand the hydrologic budget and inform water management decisions for present and future needs. The study site is 2,365 km², located in the upper Umatilla River Basin (URB) in northeastern Oregon. The Precipitation Runoff Modeling System, a distributed-parameter, physical-process watershed model, was used in this study. Model calibration yielded a Nash Sutcliffe Model Efficiency of 0.73 for both calibration (1995-2010) and validation (2010-2014) of daily streamflow. Ten Global Climate Models using Coupled Model Intercomparison Project Phase 5 experiments with Representative Concentration …

Evidence For The Drainage Of A Superglacial Lake As The Source Of Seismic Waves Recorded At A Regional Distance, Erik J. Orantes

Dissertations and Theses

Surface melting during the summer leads to the formation of lakes on the Greenland Ice Sheet surface, known as supraglacial lakes. Some of these lakes drain through cracks in their beds and release the water into the ice sheet. Previous studies suggest that some of the water reaches the bedrock, enabling basal sliding, which could potentially increase glacial discharge (Sundal et al., 2009). Das et al. (2008) showed that supraglacial lake drainage can be accompanied by seismic activity, but little work has been done on the regional detection of such waves. The present study analyzes seismic data for the period …

Climate Change Assessment In Columbia River Basin (Crb) Using Copula Based On Coupling Of Temperature And Precipitation, Yueyue Qin

Dissertations and Theses

The multi downscaled-scenario products allow us to better assess the uncertainty of the variations of precipitation and temperature in the current and future periods. Joint Probability distribution functions (PDFs), of both the climatic variables, might help better understand the interdependence of the two, and thus in-turn help in accessing the future with confidence. In the present study, we have used multi-modelled statistically downscaled ensemble of precipitation and temperature variables. The dataset used is multi-model ensemble of 10 Global Climate Models (GCMs) downscaled product from CMIP5 daily dataset, using the Bias Correction and Spatial Downscaling (BCSD) technique, generated at Portland State …

Characterization Of Tropical Clouds Using Multi-Satellite Observations, Ricardo Anderson

Dissertations and Theses

Clouds an important component of the earth-climate system and play a critical role in affecting energy and water cycle of the planet. In particular, tropical convective clouds account for the majority of the precipitation that fall on the Earth's surface. Multiple active satellite missions in recent decade such as TRMM (Tropical Rainfall Measurement Mission), and CloudSat have provided fruitful new insight into the internal structures of these tropical convective clouds. In conjunction with cloud data from ISCCP (International Satellite Cloud Climatology Project), that is based passive remote sensing technology in the visible and infrared spectrum, this allows for a more …

Intra- And Inter-Seasonal Variability Of Supra-Glacial 1 Streams And Lakes Over The West Greenland Ice Sheet 2 From High-Resolution Satellite Optical Data, Michael Gregory Brown

Dissertations and Theses

The Greenland ice sheet (GrIS) is one of the largest glacial ice masses on Earth, second only to the Antarctic ice sheet. The surface hydrology of the GrIS plays a crucial role on the surface energy and mass balance budgets of the ice sheet as a whole. Surface water, known as supra-glacial water, is seasonally found in the ablation zone and feeds the en-glacial and sub-glacial hydrological environments of the ice sheet. The spatial distribution of surface streams is poorly understood and their temporal variability is (to our knowledge) unknown. One of the reasons for the lack of knowledge on …

Quantifying The Impacts Of Initial Condition And Model Uncertainty On Hydrological Forecasts, Caleb Matthew Dechant

Dissertations and Theses

Forecasts of hydrological information are vital for many of society's functions. Availability of water is a requirement for any civilization, and this necessitates quantitative estimates of water for effective resource management. The research in this dissertation will focus on the forecasting of hydrological quantities, with emphasis on times of anomalously low water availability, commonly referred to as droughts. Of particular focus is the quantification of uncertainty in hydrological forecasts, and the factors that affect that uncertainty. With this focus, Bayesian methods, including ensemble data assimilation and multi-model combinations, are utilized to develop a probabilistic forecasting system. This system is applied …

Ccaat/Enhancer-Binding Protein Delta (C/Ebp-Delta) Expression In Antarctic Fishes: Implications For Cell Cycle And Apoptosis, Isaac Martin Sleadd

Dissertations and Theses

Chapter 1: Antarctic fishes are extremely cold adapted. Despite their inability to upregulate heat shock proteins, recent studies have demonstrated a capacity for heat response in these animals. A cDNA microarray study looked at the Notothenioid fish Trematomus bernacchii and revealed heat sensitivities for hundreds of genes, two of which code for members of the CCAAT/Enhancer-binding protein (C/EBP) family of transcription factors. These molecular switches are best known for their roles in apoptosis, inflammation and cell cycle arrest. This dissertation further elucidates the role of C/EBP-delta in the Antarctic fishes T. bernacchii and Pagothenia borchgrevinki.

Chapter 2: C/EBP-delta is constitutively …

Air-Quality And Climatic Consequences Of Bioenergy Crop Cultivation, William Christian Porter

Dissertations and Theses

Bioenergy is expected to play an increasingly significant role in the global energy budget. In addition to the use of liquid energy forms such as ethanol and biodiesel, electricity generation using processed energy crops as a partial or full coal alternative is expected to increase, requiring large-scale conversions of land for the cultivation of bioenergy feedstocks such as cane, grasses, or short rotation coppice. With land-use change identified as a major contributor to changes in the emission of biogenic volatile organic compounds (BVOCs), many of which are known contributors to the pollutants ozone (O₃) and fine particulate matter …

Glacier Change In The North Cascades, Washington: 1900-2009, Kristina Amanda Dick

Dissertations and Theses

Glaciers respond to local climate changes making them important indicators of regional climate change. The North Cascades region of Washington is the most glaciated region in the lower-48 states with approximately 25% of all glaciers and 40% of the total ice-covered area. While there are many on-going investigations of specific glaciers, little research has addressed the entire glacier cover of the region. A reference inventory of glaciers was derived from a comparison of two different inventories dating to about 1958. The different inventories agree within 93% of total number of glaciers and 94% of total ice-covered area. To quantify glacier …

Climate Change Impact On The Spatio-Temporal Variability Of Hydro-Climate Extremes, Mohammad Reza Najafi

Dissertations and Theses

The rising temperature of the earth due to climate change has shown to alter the variations of hydro-climate variables, including their intensities, frequencies and durations. Extreme events such as floods are, in particular, susceptible to any disturbances in climate cycles. As such it is important to provide policymakers with sufficient knowledge about the probable impacts of climate change on hydrologic extremes and most importantly on floods, which have the highest impacts on the societies. For this reason analysis of hydro-climate extremes is commonly performed using data at each site (or grid cell), however due to the limited number of extreme …

Where Is The Rain-On-Snow Zone In The West-Central Washington Cascades?: Monte Carlo Simulation Of Large Storms In The Northwest, Matthew John Brunengo

Dissertations and Theses

Rain-on-snow (ROS) occurs when warm, wet air moves into latitudes and/or elevations having vulnerable snowpacks, where it can alter water inputs to infiltration, runoff and erosion. The Pacific Northwest is particularly susceptible: winter storms off the Pacific cause locally heavy rain plus snowmelt almost annually, and disastrous flooding and landsliding intermittently. In maritime mountainous terrain, the effects seem more likely and hydrologically important where warm rains and seasonal snowpacks are liable to coincide, in middle elevations. Several questions arise: (1) In the PNW, does ROS affect the long-term frequency and magnitude of water delivery to the ground, versus total precipitation …

Late Pleistocene And Holocene Aged Glacial And Climatic Reconstructions In The Goat Rocks Wilderness, Washington, United States, Joshua Andrews Heard

Dissertations and Theses

Eight glaciers, covering an area of 1.63 km2, reside on the northern and northeastern slopes of the Goat Rocks tallest peaks in the Cascades of central Washington. At least three glacial stands occurred downstream from these glaciers. Closest to modern glacier termini are Little Ice Age (LIA) moraines that were deposited between 1870 and 1899 AD, according to the lichenometric analysis. They are characterized by sharp, minimally eroded crests, little to no soil cover, and minimal vegetation cover. Glacier reconstructions indicate that LIA glaciers covered 8.29 km2, 76% more area than modern ice coverage. The average LIA equilibrium line altitude …

Climate Change Effects And Water Vulnerability In The Molalla Pudding River Basin, Oregon, Usa, Susan Amelia Wherry

Dissertations and Theses

Water management plans are typically developed using historical data records and historical return periods for extreme events, such as floods or droughts. Since these analyses of return periods typically assume a certain degree of stationarity (constant mean, standard deviation, distribution) in hydrologic variables, the potential future impacts of climate change are excluded. In developing water management plans, predicted changes to climate variables should be considered to evaluate the degree of non-stationarity that may exist in the future. In this way, regions most sensitive to climate change can be identified and managed appropriately. This study performed such a task by using …

Community Earth System Model: Implementation, Validation, And Applications, William Christian Porter

Dissertations and Theses

The Community Earth System Model (CESM) is a coupling of five different models which are combined to simulate the dynamic interactions between and within the Earth's atmosphere, ocean, land, land-ice, and sea-ice. In this work, the installation and testing of CESM on Portland State University's Cluster for Climate Change and Aerosol Research (CsAR) is described and documented, and two research applications of the model are performed. First, the improved treatment of cloud microphysics within recent versions of CESM's atmospheric module is applied to an examination of changes in shortwave cloud forcing (SWCF) and results are compared to output from older …

Spatial And Temporal Characteristics Of Surface Air Temperature For Portland, Oregon, Li-Min Yang

Dissertations and Theses

This study examines the spatial and temporal characteristics of the surface air temperature in Portland, Oregon. Spatial temperature patterns indicate that the dominant control factors on seasonal temperature distribution are local topography, elevation, and urban-rural differences in surface structure. A heat island exists in the Portland area; the intensity of the heat island rang€s from 4° to 10° F, and varies throughout the year. The strongest heat island is found in the July minimum temperature. Temperature distribution in Portland and the adjacent area is affected by winds and rainy conditions, but less influenced under overcast skies. The long-term temperature over …