Earth Sciences Commons^™

Enhancing A Computer Model To Evaluate Rainwater Harvesting And Reuse Strategies For Landscape Irrigation Under Current And Future Climate Conditions, Siyu Li

Electronic Theses & Dissertations (2024 - present)

Urbanization and climate change have detrimental impacts on water quantity and quality. Rainwater harvesting/reuse for landscape irrigation with rain barrels/cisterns, which can assist urban hydrological/water quality restoration and provide a beneficial resource for irrigating landscape, holds significant potentials in urban areas under current and future climates. However, the impacts of rainwater harvesting/reuse strategies for landscape irrigation under a changing climate need to be comprehensively evaluated to assist decision-making. In addition, a comprehensive tool is needed to help stakeholders develop efficient strategies to harvest rainwater for landscape irrigation with rain barrels/cisterns.

To address the needs, the simulation of the sub-daily hydrological …

A Hybrid Algorithm To Dual Sparse Sampling Measurement In Time-Resolved Electromagnetic Near-Field Scanning, Yanming Zhang, Steven Gao, Lijun Jiang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Time-resolved electromagnetic near-field scanning is vital for antenna measurement and addressing complex electromagnetic interference and compatibility issues. However, the swift acquisition of high-resolution spatiotemporal data remains challenging due to physical constraints, such as moving the probe position and allowing sufficient time for sampling. This paper introduces a novel hybrid approach that combines Kriging for sparse spatial measurement, compressed sensing (CS) for sparse temporal sampling, and dynamic mode decomposition (DMD) for a comprehensive analysis of dual-sparse sampling electromagnetic near-field data. CS optimizes sparse sampling in the time domain, capitalizing on the inherent sparsity within electromagnetic radiated signals, resulting in reliable representation …

A Data-Driven Approach To Time-Domain Electromagnetic Modeling Based On Dynamic Mode Decomposition, Yanming Zhang, Steven Gao, Lijun Jiang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

This paper presents a data-driven methodology that utilizes Dynamic Mode Decomposition (DMD) for the time-domain (TD) electromagnetic (EM) modeling of microwave devices. As an unsupervised machine learning technique, DMD leverages a limited set of unlabeled spatio-temporal electromagnetic (EM) data to determine DMD eigenvalues and eigenmodes. Then, the obtained DMD model reconstructs the dynamics as a series of exponential terms based on linear assumptions. The effectiveness of this approach is demonstrated through the TD EM modeling of photonic crystal waveguides. Comparative analysis with the finite-difference time-domain (FDTD) method shows that the DMD model not only achieves precise modeling but also facilitates …

Would Self-Supported Fracture Contribute To The Hydrocarbon Production In Shale Reservoir Besides Proppant-Supported Fracture, Y. Sun, G. Li, S. Zeng, J. Wu, J. Liu, M. Xu, C. Dai, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

During hydraulic fracturing in deep shale gas reservoirs, it is difficult to pump proppants long distances, and self-supported fractures are formed at the far and upper ends of the fractures. The self-supported fracture could hold the fracture space by its surface structure again fracture closure. However, it faces various aspects of impairment during shale gas reservoir development, which affect its conductivity. Among the impairment, long-term production results in a decline of bottom hole pressure, which will compact the fracture space, and self-supported fractures without proppant are more sensitive than those with proppant. In this paper, we conducted a series of …

An Unsupervised Learning Framework For Determining The Excitation Coefficients Using Near-Field Antenna Measurements, Yanming Zhang, Peifeng Ma, Steven Gao, Lijun Jiang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

This article presents a novel unsupervised learning framework based on multiscale dynamic mode decomposition for determining the excitation coefficients of antennas using time-domain near-field measurements. The proposed framework integrates temporal multiscale analysis to extract a joint distribution of frequency, damping factors, and spatial modes, enabling precise extraction of excitation frequencies, rising/falling edges, and phases without labeled data. We validate the effectiveness of the proposed approach through two examples involving on-off keying modulation and a phase-shift dipole antenna. It is found that the proposed method performs well in handling nonstationary excitation signals and proves particularly advantageous for calibrating tunable antenna systems. …

Diatom Productivity And Nutrient Dynamics In The Ross Sea, Antarctica During Warm Events In The Neogene, Marialena Christopoulou

Graduate Research Theses & Dissertations

Increased melting of the Antarctic Ice Sheet (AIS) in recent decades, has had a significant impact on many aspects of the global ocean. Models indicate that by the end of the 21st century atmospheric carbon dioxide (CO2) concentrations may exceed 500 ppm, and the average global temperature will likely warm by more than 2°C. However, data that provide model constraints on potential feedbacks in ice-ocean-atmosphere system are limited by short-timescales (e.g., decadal- to centennial-scale) and incomplete spatial coverage. In particular, little is known about the impacts of future warming and widespread melting of AIS on marine biological productivity, silicate weathering …

Hunting Types In North American Eocene And Oligocene Carnivores And Implications For Nimravid Extinction, Miguel Andres Castellanos

Graduate Research Theses & Dissertations

The late Eocene and Oligocene is traditionally seen as a time of great climactic shift, with open habitats beginning to appear and forests receding. This time period saw both the diversification and subsequent extinction of North American nimravids. The causes of the extinction of this early sabertooth group in the Arikareean remain unclear. One possibility for their decline is that nimravids were competitively disadvantaged in open habitats relative to contemporary, possibly more cursorial caniform predators. Here I analyze and compare the hunting styles of Eocene and Oligocene predators in correlation with their ecological implications via discriminant function analysis of the …

Tracing Past Climate Signals Through Multi-Proxy Analysis: Insights From Sedimentary Plant Wax Hydrogen Isotope Data And Long-Term Hydroclimate Records In Estonia, Mariliis Eensalu

Graduate Research Theses & Dissertations

In light of the rising global temperatures, there is an increasing need to understand the potential shifts in hydroclimate. Past climate reconstructions offer a glimpse into the possible temperature-moisture dynamics by providing quantitative constraints for hydroclimate variability under different temperature conditions, which can ultimately aid in decreasing the uncertainty in future climate projections. The research presented in this dissertation focuses on utilizing various proxies to reconstruct past hydroclimate conditions, particularly in the Baltic region, with a specific emphasis on Estonia. The second and third chapter aim to improve the understanding of sedimentary plant wax hydrogen isotope (δ2H) data by first …

Temporal Microplastic Concentration Fluctuations Within An Agricultural Creek And Groundwater In Relation To Farming Practices, Jennifer Abel

Graduate Research Theses & Dissertations

Microplastics (MPs) in agriculture have been well-documented. Agrochemicals, organic fertilizers, and farming equipment all contribute plastic to agricultural soils, groundwater, and surface water and are utilized in different capacities throughout the year. It is unknown how the specific utilization of these products affects the concentration of MPs being input into the environment. Previous research has been primarily related to detection and transport of MPs in soils, groundwater, and surface water. I am unaware of any studies that have taken into consideration farming practices and seasons, and how they may affect any fluctuations in MP concentrations. Water samples (20 L) were …

Alfred Russel Wallace Notes 29. Extraterrestrial Entertainment: Are We Being Monitored By Alien Beings?, Charles H. Smith

Faculty/Staff Personal Papers

Alfred Russel Wallace (1823−1913) was an early advocate for the rational assessment of likelihood of extraterrestrial life. Current efforts to evaluate the situation have ranged from the heavily self-indulgent to the more objective, and it is still often difficult to decide just how much of the information we are receiving on the subject is dependable. An attempt is made here to cut through the haze and reduce the matter to elementals.

Nitrogen Fertilizer Placement And Rate Impacts Sunflower Seed Yield, Oil And Protein Content, Rojina Kafle

Electronic Theses and Dissertations

South Dakota accounts for about 36% of the total US commercial sunflower production and nitrogen is a major input. Costs related to N fertilizer demand economically optimum N rates. This study investigated the impact of the N fertilizer placement method (broadcast vs band) and rate (0, 28, 56, 84, 112, 140 kg N ha-1) on leaf chlorophyll content, head diameter, seed yield, seed oil, and protein concentration of three sunflower hybrids in 2022 and 2023. The experiment was conducted at Brookings (eastern SD- conventional till, 66 cm rainfall) using an oil-type hybrid and at central SD sites (no-till, 57 cm …

Characterizing Mountainous Bedrock Groundwater Systems Across Gradients In Topography And Lithology In Western Montana, David L. Baude

Graduate Student Theses, Dissertations, & Professional Papers

Mountain aquifer groundwater systems remain one of the least understood hydrologic systems in upland hydrology. In this study, we aim to characterize bedrock groundwater system dynamics and bedrock-saprolite interactions across a variety of landscape positions and lithology. We investigate groundwater hydraulics, recharge temperature and elevation, residence times, and bedrock recharge rates across two mountainous headwater catchments in west central Montana. We used a suite of environmental tracers (³H, CFCs, SF₆, and ⁴He) and residence time distribution models to estimate groundwater mean residence times over a range of timescales from decades to millennia. Tracers were sampled …

Investigating The Roles Of Plants, Fungi, And Biocrusts In Nutrient Movement Within Dryland Ecosystems, Catherine E. Cort

Open Access Theses & Dissertations

In dryland ecosystems, plant productivity and microbial decomposition are often separated in space and time due to the asynchronous availability of soil moisture and organic matter inputs. It has been proposed that fungi play a key functional role in connecting these cycles by facilitating movement of water, carbon (C), and nitrogen (N) through a network of shared hyphae between plant roots and biological soil crust (biocrust) communities at the soil surface. This connection, also known as the â??fungal loop,â?? effectively re-couples processes of nutrient release and uptake between primary producers and minimizes ecosystem N losses due to leaching, erosion, and …

Revised Geologic Map And Structural Interpretation Of The Mineral King Pendant, Southern Sierra Nevada, California (Usa): Evidence For Kilometer-Scale Folding And Structural Imbrication Of A Permian To Mid-Cretaceous Volcanosedimentary Assemblage, David C. Greene, Jade Star Lackey, Erik W. Klemetti

Faculty Publications

No abstract provided.

Characterization Of Geuda Sapphires From Sri Lanka, Hussain Akiff Mohamed Faleel

Chulalongkorn University Theses and Dissertations (Chula ETD)

Geuda sapphire samples from the Kataragama and Ratnapura deposits in Sri Lanka were classified into milky, silky, and diesel varieties. Each sample was sliced into two pieces and subjected to two different heat treatments. The first slice was heated to 1750°C in a gas furnace using LPG, creating an oxygen-reduced environment, while the second slice was annealed at 1650°C in an electric furnace under oxidizing condition. Both heating methods produced similar results for the milky and diesel geuda varieties. However, in the silky geuda, which contained needle-like ilmenite inclusions, the gas furnace under oxygen-reduced conditions yielded more pronounced effects. In …

Basal Topography And Carbon Accumulation Rate Of A Rare Northern California Coastal Fen, Sarah Leidinger

Cal Poly Humboldt theses and projects

Increasingly, the importance of peatlands as biodiversity hotpots, year-round water storage features, and significant carbon sinks are being recognized. Despite this, they are one of the most vulnerable ecosystems globally. While some peatland conservation and restoration initiatives are being developed, a greater understanding of small peatlands is needed to make management decisions. This study aims to determine the timing of peat formation, peat volume, and carbon accumulation rates of the Conspicuous Scoop Fen, a small (2.1-acre) fen near Bridgeville, California (~840 m.a.s.l.). During the summers of 2022 and 2023, I collected 39 m of peat cores at 14 sampling locations. …

Insect Frass Fertilizer As A Regenerative Input For Improved Biological Nitrogen Fixation And Sustainable Bush Bean Production, Agnes Chepkorir, Dennis Beesigamukama, Harun I. Gitari, Shaphan Y. Chia, Sevgan Subramanian, Sunday Ekesi, Birachi Eliud Abucheli, Jean Claude Rubyogo, Theodore Zahariadis, Gina Athanasiou, Aikaterini Zachariadi, Vasileios Zachariadis, Abdou Tenkouano, Chrysantus M. Tanga

All Peer-Reviewed Publications

Bush bean (Phaseolus vulgaris L.) production is undermined by soil degradation and low biological nitrogen fixation (BNF) capacity. This study evaluated the effect of black soldier fly frass fertilizer (BSFFF) on bush bean growth, yield, nutrient uptake, BNF, and profitability, in comparison with commercial organic fertilizer (Phymyx, Phytomedia International Ltd., Kiambu, Kenya), synthetic fertilizer (NPK), and rhizobia inoculant (Biofix, MEA Fertilizers, Nairobi, Kenya). The organic fertilizers were applied at rates of 0, 15, 30, and 45 kg N ha−1 while the NPK was applied at 40 kg N ha−1, 46 kg P ha−1, and 60 kg K ha−1. The fertilizers …

Evidence That Ericoid Mycorrhizal Shrubs Can Outcompete Ectomycorrhizal Trees For Nitrogen In Tannin-Rich Litter, Kai C. Rains, Caroline Bledsoe, Tamara E. Kraus, Nina Wurzburger

School of Geosciences Faculty and Staff Publications

Mycorrhizal associations of trees play a key role in ecosystem biogeochemistry, yet we know relatively little about the nutrient acquisition strategies of ericoid mycorrhizal (ErM) shrubs, despite their prevalence in forest understories. ErM shrubs tend to produce litter with high concentrations of polyphenols, which form decay-resistant complexes with organic nitrogen (N). Some ErM fungi appear capable of producing a diverse suite of extracellular enzymes, but it is unclear whether this enables ErM shrubs to acquire the N from their own litter, and whether this ability is greater than that of ectomycorrhizal (EcM) trees, with which they commonly co-occur. Here, we …

Uav-Based Wetland Monitoring: Multispectral And Lidar Fusion With Random Forest Classification, Robert Van Alphen, Kai C. Rains, Mel Rodgers, Rocco Malservisi, Timothy H. Dixon

School of Geosciences Faculty and Staff Publications

As sea levels rise and temperatures increase, vegetation communities in tropical and sub-tropical coastal areas will be stressed; some will migrate northward and inland. The transition from coastal marshes and scrub–shrubs to woody mangroves is a fundamental change to coastal community structure and species composition. However, this transition will likely be episodic, complicating monitoring efforts, as mangrove advances are countered by dieback from increasingly impactful storms. Coastal habitat monitoring has traditionally been conducted through satellite and ground-based surveys. Here we investigate the use of UAV-LiDAR (unoccupied aerial vehicle–light detection and ranging) and multispectral photogrammetry to study a Florida coastal wetland. …

Optimizing Field-Linked Simulations Of Dry Season Uptake And Monsoon Infiltration Within An Aspen-Mixed Conifer Forest, Raymond J. Hess

Master's Theses

Climate models forecast that headwater catchments in the western U.S. will undergo a reduction in snowpack, early season snowmelt, and increases in evapotranspiration. The resulting extended dry season will stress vegetation in mountainous watersheds throughout the Upper Colorado River Basin. We investigate infiltration patterns and root water uptake in response to dry season disturbances within the East River watershed in Colorado. To do this, we collected soil cores, measured matric potential and sap flow, and monitored tree xylem and soil for stable isotopes of water (2H, 18O) in two soil profiles to 90 cm depth (with three Engelmann spruce and …

Small-Strain Site Response Of Soft Soils In The Sacramento-San Joaquin Delta Region Of California Conditioned On Vₛ₃₀ And Mhvsr, Tristan E. Buckreis, Jonathan P. Stewart, Scott J. Brandenberg, Pengfei Wang

Civil & Environmental Engineering Faculty Publications

Sites located in the Sacramento-San Joaquin Delta region of California typically have peaty-organic soils near the ground surface, which are characteristically soft, with shear wave velocities as low as 30 m/s. These unusually soft geotechnical conditions, which are outside the range of applicability of existing ergodic site amplification models, can be anticipated to produce significant site effects during earthquake shaking. We evaluate site response for 36 seismic stations in the Delta region using non-ergodic methods with low-amplitude ground motion data. We model first-order site effects using a period-dependent relation conditioned on the 30 m time-averaged shear wave velocity (V …

Investigating The Viability Of Low Frequency Mhvsr Estimates Using Deep Shear Wave Velocity Profile, T. Mai, C. C. Nweke, P. Wang, F. J. Ornelas

Civil & Environmental Engineering Faculty Publications

Site response describes the alterations of seismic energy due to its interaction with subsurface geological interfaces and structures, which is usually estimated by one dimensional (1D) ground response analysis (GRA). However, 1D GRA requires subsurface information (e.g., shear wave velocity profile), which makes it not widely applicable, particularly for the sites where subsurface information is unavailable. Alternatively, the microtremor horizontal-to-vertical spectral ratio (mHVSR) from three-component recordings of ambient noise on the ground surface is easily measured and is believed to have the potential for site response prediction (the peaks in mHVSR are strongly associated with the site resonant frequencies). However,the …

Contribution Of High Turbidity To Tidal Dynamics In A Curved Channel In Zhoushan Islands, China, Li Li, Fangzhou Shen, Zhiguo He, Gangfeng Ma, Jiachen Wang, Kailong Huangfu

Civil & Environmental Engineering Faculty Publications

The curved tidal channel, Luotou Deep-water Navigational Channel, is the main channel of the Ningbo Zhoushan Port, which is ranked first in the world. Tidal dynamics in the channel are spatially and temporally asymmetric. In this study, the three-dimensional tidal dynamics in the channel were analyzed using field data and simulated using FVCOM. The results show that the tides in the channel flood/ebb along the northern/southern bank near the bottom/surface layer and these asymmetries are due to the imbalanced Coriolis force, centrifugal force, sea-level gradient, and density gradient. Residual current velocity peaks (0.7 m/s) in the middle of the channel …

A General Framework For Modeling Subregional Path Effects, T. E. Buckreis, P. Wang, S. J. Brandenberg, J. P. Stewart

Civil & Environmental Engineering Faculty Publications

Next Generation Attenuation (NGA) West2 ground motion models (GMMs) include regional path adjustments for broad jurisdictional regions, which necessarily averages spatially variable path effects within those regions. We extend that framework to account for systematic variations in attenuation within subregions defined in consideration of geologic differences. In recent years, cell-based methods which systematically account for spatial variations by summing the attenuation effects over a fine discretization of uniform-rectangular cells (e.g., Dawood and Rodriquez-Marek 2013; Kuehn et al. 2019) have been shown to be an effective alternative to regionalization and a step towards modelling non-ergodic path effects. The main drawbacks of …

Integrating Climatological-Hydrodynamic Modeling And Paleohurricane Records To Assess Storm Surge Risk, Amirhosein Begmohammadi, Christine Y. Blackshaw, Ning Lin, Avantika Gori, Elizabeth Wallace, Kerry Emanuel, Jeffrey P. Donnelly

OES Faculty Publications

Sediment cores from blue holes have emerged as a promising tool for extending the record of long-term tropical cyclone (TC) activity. However, interpreting this archive is challenging because storm surge depends on many parameters including TC intensity, track, and size. In this study, we use climatological-hydrodynamic modeling to interpret paleohurricane sediment records between 1851 and 2016 and assess the storm surge risk for Long Island in The Bahamas. As the historical TC data from 1988 to 2016 is too limited to estimate the surge risk for this area, we use historical event attribution in paleorecords paired with synthetic storm modeling …

Re-Evaluating Hydrogen Sulfide As A Sink For Cadmium And Zinc In The Oxic To Suboxic Upper Water Column Of The Pacific Ocean, N. R. Buckley, E. E. Black, J. A. Kenyon, N. T. Lanning, M. Sieber, T. M. Conway, J. N. Fitzsimmons, G. A. Cutter

OES Faculty Publications

Hydrogen sulfide is produced by heterotrophic bacteria in anoxic waters and via carbonyl sulfide hydrolysis and phytoplankton emissions under oxic conditions. Apparent losses of dissolved cadmium (dCd) and zinc (dZn) in oxygen minimum zones (OMZs) of the Atlantic and Pacific Oceans have been attributed to metal-sulfide precipitation formed via dissimilatory sulfate reduction. It has also been argued that such a removal process could be a globally important sink for dCd and dZn. However, our studies from the North Pacific OMZ show that dissolved and particulate sulfide concentrations are insufficient to support the removal of dCd via precipitation. In contrast, apparent …

Ratification Of The Base Of The Ics Geological Time Scale: The Global Standard Stratigraphic Age (Gssa) For The Hadean Lower Boundary, Janna Halla, Nora Noffke, Humberto Reis, Stanley Awramik, Andrey Bekker, Alexander Brasier, Flávia Callefo, Adrita Choudhury, Jan-Peter Duda, Christopher Fedo, Douglas Galante, Jessica Haddock, Peter Haines, Linda Hinnov, Axel Hofmann, Martin Homann, David Huston, Simon Johnson, Linda Kah, Martin Whitehouse, Et Al.

OES Faculty Publications

The base of the ICS (International Commission on Stratigraphy) Geological Time Scale was ratified in 2022 by defining a new Global Stratigraphic Standard Age (GSSA) for the lower boundary of the Hadean Eon (formerly 4000-3600 Ma); the age of the Solar System based on the oldest solids, calcium-aluminium inclusions (CAIs), generated in the protoplanetary disk. The formal GSSA for the Hadean base is the oldest reliable, weighted mean U-corrected Pb-Pb age of 4567.30 ± 0.16 Ma obtained for CAIs in primitive meteorites Allende and Efremovka. This age is supported by the 4568-4567 Ma U-corrected Pb-Pb ages of chondrules in Northwest …

Ice-Marginal Lava Delta In Iceland Found On A Nondescript Shallow Slope: An Unexpected Record Of Ice Thickness Late In Deglacian, Audrey Putnam, Kirsten Siebach, Candice Bedford, Sarah Simpson, Elizabeth Rampe, Joseph Tamborski, Michael Thorpe

OES Faculty Publications

Volcanism increases when glaciers melt because isostatic rebound during deglaciation decreases the pressure on the mantle, which enhances decompression melting. Anthropogenic climate change is now causing ice sheets and valley glaciers to melt around the world and this deglaciation could stimulate volcanic activity and associated hazards in Iceland, Antarctica, Alaska, and Patagonia. However, current model predictions for volcanic activity associated with anthropogenic deglaciation in Iceland are poorly constrained, in part due to uncertainties in past volcanic output over time compared to ice sheet arrangements. Further work specifically characterizing glaciovolcanic and ice-marginal volcanoes in Iceland is needed to reconstruct volcanic output …

Editorial: The Marine Iodine Cycle, Past, Present, And Future, Rosie Chance, Gregory A. Cutter, Dalton S. Hardisty, Anoop S. Mahajan

OES Faculty Publications

In this Research Topic, we bring together ten articles from the diverse research communities interested in the marine iodine cycle, including paleoceanographers, atmospheric chemists, and biogeochemists. The physical chemistry underpinning iodine’s chemical speciation and transformations in the ocean is reviewed by Luther; this paper provides a theoretical basis for the field observations presented in this Research Topic.

An Inconsistent Enso Response To Northern Hemisphere Stadials Over The Last Deglaciation, Ryan H. Glaubke, Matthew W. Schmidt, Jennifer E. Hertzberg, Lenzie G. Ward, Franco Marcantonio, Danielle Schimmenti, Kaustubh Thirumalai

OES Faculty Publications

The dynamics shaping the El Niño-Southern Oscillation's (ENSO) response to present and future climate change remain unclear, partly due to limited paleo-ENSO records spanning past abrupt climate events. Here, we measure Mg/Ca ratios on individual foraminifera to reconstruct east Pacific subsurface temperature variability, a proxy for ENSO variability, across the last 25,000 years, including the millennial-scale events of the last deglaciation. Combining these data with proxy system model output reveals divergent ENSO responses to Northern Hemisphere stadials: enhanced variability during Heinrich Stadial 1 (H1) and reduced variability during the Younger Dryas (YD), relative to the Holocene. H1 ENSO likely intensified …