Physical Sciences and Mathematics Commons^™

An Evaluation Of Spatial Variability Of Water Stress Index Across The United States: Implications Of Supply And Demand In The East Vs The West, Jennifer Ann Roath

Open Access Theses

In order to support both human and environmental needs, high quality fresh water must be available when and where it is required. As a metric for indicating unsustainable water usage, WSI is only useful when the values reflect accurate interactions between supply and demand; however, the complexity of temporal and spatial variability of available fresh water complicates the analysis of water stress.

The overall goal of this project was to investigate the spatial variability of water stress across the United States and the appropriate spatial scale for management decisions. To accomplish this, a national dataset describing spatial distribution and breakdown …

The Influence Of The Tibetan Plateau Elevation On The Global And Asian Monsoons, Rene Paul Acosta

Open Access Theses

It has been long hypothesized that large-scale topographic changes, such as the surface uplift of the Tibetan Plateau, impacts the development of the South Asian and East Asian monsoons and influences other monsoon regions. However, recent modeling has shown that spatial distribution of the global monsoon, which includes the South Asian and East Asian monsoons is largely unaffected by the elevation of the plateau. In this study, we present results from a series of modern day simulations using CESM1.0 in a mixed-layer (slab ocean) configuration. The Tibetan Plateau height is varied from double that of the modern maximum plateau elevation …

Callovian (Upper Middle Jurassic) Magnetostratigraphy: A Composite Polarity Pattern From France, Britain And Germany, And Its Correlation To The Pacific Marine Magnetic Anomaly Model, Rachel Anne Gipe

Open Access Theses

Callovian strata from sixteen exposures across western Europe produced a nearly continuous composite geomagnetic polarity reference sequence spanning the latest Bathonian (Clydoniceras discus Zone) through the entire Callovian and into the earliest Oxfordian (Quenstedtoceras mariae zone). This sequence is compiled from multi-section sequences from France and England, a section in southern Germany, and a section on the Isle of Skye (Scotland). These sections are calibrated with ammonite biostratigraphy, brachiopod associations and sequence stratigraphy. Over 400 oriented core samples were subjected to progressive thermal demagnetization and filtered according to magnetic behavior; the highest quality suite produced mean paleopoles of 67.3°N, 174.8°E …

Improving Model Performance For Invasive Plant Species Distribution Using Global-Scale Presence-Only Data: Parameterization And Data Quality, Feng Yu

Open Access Theses

Invasive species have significant ecological and economic impacts. To control species' invasion, risk assessment provides the most essential information for identification and evaluation of the potential risk of the invasive species, especially in their early invasion stages. Species distribution models (SDMs) is the foundation for risk assessment, in terms of both the practical and theoretical interest in our understanding of species invasion process. SDMs contribute to the proactive invasion management and the test of ecological or biogeographical hypotheses about species distributions in relation to their environment.

However, modeling of invasive species at large spatial scale (i.e., cross-continental) is rarely discussed. …

Swat Model Simulation Of Bioenergy Crop Impacts In A Tile-Drained Watershed, Chelsie Marie Werling Boles

Open Access Theses

Tile drains are an important component of agricultural production in the Midwest, and their inclusion in modeling studies is important in watersheds where they are a principal hydrologic pathway. The new tile drainage simulation method in the Soil Water Assessment Tool (SWAT) was parameterized and tile flow results were compared with reviewed literature. Streamflow, sediment, and nutrient outputs were compared to measured values and simulated crop yields were examined with respect to average county yields. Plant growth stressors were examined to account for differences between simulated and published yields. The bioenergy crop switchgrass (Panicum virgatum) was applied over …

Identifying Ditch Geometry And Top Of The Bank Location Using Airborne Lidar Point Cloud, Naime Celik

Open Access Theses

The geometry of agricultural drainage ditches is very important in crop production as it impacts drainage of cropland and affects vegetation and soil erosion along the banks of the ditches. Thus, implementation of water conservation and management practices in engineered and natural ditches necessitates determination of ditch geometry along the reach of the ditch. This study explores the use of airborne commercial Light Detection and Ranging (LiDAR) technology to identify the top of the ditch banks. The method was developed to obtain the normalized cross sectional shape of the ditch using one-dimensional spline fits to ground classified points from the …

Slurry Seeding Cover Crops, Edwin Alexander Suarez

Open Access Theses

Cover crops improve soil quality through increased organic matter, biological activity, aggregate stability, water infiltration, and nutrient cycling. Slurry seeding, the co-application of cover crop seed and swine (Sus domesticus) manure, is a new practice that saves fuel, time and labor. High salinity and/or ammonia, among other components in swine manure, may reduce cover crop seed germination and limit the use of slurry seeding. Ten cover crop species were evaluated to compare the effects of swine manure components on cover crop seed germination. Seed germination percentages and rates were affected by swine manure but not by equivalent salinity levels established …