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Full-Text Articles in Physical Sciences and Mathematics

Hydrodynamic Controls On The Morphodynamic Evolution Of Subaqueous Landforms, Timothy L. Nelson Dec 2017

Hydrodynamic Controls On The Morphodynamic Evolution Of Subaqueous Landforms, Timothy L. Nelson

University of New Orleans Theses and Dissertations

The southern Chandeleur Islands are an ideal setting to study shoal evolution given their history of submergence and re-emergence. Here, numerical models shed light on the attendant processes contributing to shoal recovery/reemergence following a destructive storm event. Simulations of a synthetic winter storm along a cross-shore profile using Xbeach shows that convergence of wave-induced sediment transport associated with repeated passage of cold-fronts initiates aggradation, but does not lead to reemergence. A Delft3d model of the entire island chain shows that as these landforms aggrade alongshore processes driven by incident wave refraction on the shoal platform, backbarrier circulation and resulting transport …


A Geophysical Model For The Origin Of Volcano Vent Clusters In A Colorado Plateau Volcanic Field, Fanghui Deng, Charles B. Connor, Rocco Malservisi, Laura J. Connor, Jeremy White, Aurélie Germa, Paul H. Wetmore Nov 2017

A Geophysical Model For The Origin Of Volcano Vent Clusters In A Colorado Plateau Volcanic Field, Fanghui Deng, Charles B. Connor, Rocco Malservisi, Laura J. Connor, Jeremy White, Aurélie Germa, Paul H. Wetmore

School of Geosciences Faculty and Staff Publications

Variation in spatial density of Quaternary volcanic vents, and the occurrence of vent clusters, correlates with boundaries in Proterozoic crust in the Springerville volcanic field (SVF), Arizona, USA. Inverse modeling using 538 gravity measurements shows that vent clusters correlate with gradients in the gravity field due to lateral variation in crustal density. These lateral discontinuities in the crustal density can be explained by boundaries in the North American crust formed during Proterozoic accretion. Spatial density of volcanic vents is low in regions of high‐density Proterozoic crust, high in areas of relatively low density Proterozoic crust, and is greatest adjacent to …


Ionospheric Gravity Waves Driven By Oceanic Gravity Waves In Resonance: A Modeling Study In Search Of Their Spectra, Michael P. Hickey, Yonghui Yu Sep 2017

Ionospheric Gravity Waves Driven By Oceanic Gravity Waves In Resonance: A Modeling Study In Search Of Their Spectra, Michael P. Hickey, Yonghui Yu

Publications

Ionospheric observations associated with the 2011 Tohoku tsunami have revealed gravity waves having spectral characteristics that depend on their proximity to the epicenter. There is a preponderance of medium-scale waves in the vicinity of the epicenter, a significant bifurcation into short- and long-period waves over the Hawaiian archipelago, and a narrow and rich spectrum of waves over the West Coast and inland of the United States (U.S.). Guided by these previous observations, we consider wave sources as triads of nonlinearly interacting oceanic gravity waves, whose wave parameters satisfy resonant conditions. These waves are simulated using a 2-D nonlinear model describing …


Numerical Simulations Of The Biogeochemical Impact Of Atmospheric Nitrogen Deposition On Surface Waters Of The Western North Atlantic, Pierre St-Laurent, Marjorie A.M. Friedrichs Sep 2017

Numerical Simulations Of The Biogeochemical Impact Of Atmospheric Nitrogen Deposition On Surface Waters Of The Western North Atlantic, Pierre St-Laurent, Marjorie A.M. Friedrichs

Data

The impacts of atmospheric nitrogen deposition on the chlorophyll and nitrogen dynamics of surface waters in the western North Atlantic (25-45N, 65-80W) were examined with a biogeochemical ocean model forced with a regional atmospheric chemistry model. The model simulations cover the period 2004 to 2008 and are fully described in the following reference: St-Laurent, P., et al., Impacts of atmospheric nitrogen deposition on surface waters of the western North Atlantic mitigated by multiple feedbacks, J. Geophys. Res. Oceans, vol.122, doi:10.1002/2017jc013072.


Evaluating The Impacts Of Grassland Conversions To Experimental Forest On Groundwater Recharge In The Nebraska Sand Hills, Zablon A. Adane Apr 2017

Evaluating The Impacts Of Grassland Conversions To Experimental Forest On Groundwater Recharge In The Nebraska Sand Hills, Zablon A. Adane

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The Nebraska Sand Hills grasslands provide the greatest groundwater recharge rates in the High Plains Aquifer. However, the grasslands and their ecological services have become vulnerable to land use change and degradation. This study used a series of field data to investigate the effects of grassland conversions to forest on recharge rates in a century-old experimental forest in the Sand Hills. The results show that the impact of grassland conversion on recharge was dependent on the species and plantation density. Estimated recharge rates beneath the dense plantations represent reductions of 86–94% relative to the native grassland. Results of 1H …


Modeling The Mitigation Of Seawater Intrusion By Pumping Brackish Water From The Coastal Aquifer Of Wadi Ham, Uae, Modou A Sowe Apr 2017

Modeling The Mitigation Of Seawater Intrusion By Pumping Brackish Water From The Coastal Aquifer Of Wadi Ham, Uae, Modou A Sowe

Theses

The control and management of seawater intrusion in coastal aquifers is a major challenge in the field of water resources management. Seawater intrusion is a major problem in the coastal aquifer of Wadi Ham, United Arab Emirates caused by intensive groundwater abstraction from increased agricultural activities. This has caused the abonnement of salinized wells and ultimately affected farming activities and domestic water supply in the area. In this study, the 3D finite element groundwater flow and solute transport model, FEFLOW was used to simulate pumping of brackish water from the intrusion zone to control seawater intrusion in the aquifer. The …


Impact Of The Capillary Pressure-Saturation Pore-Size Distribution Parameter On Geological Carbon Sequestration Estimates, Chu-Lin Cheng, Edmund Perfect, T. Edward Yu, Michael J. Gragg Jan 2017

Impact Of The Capillary Pressure-Saturation Pore-Size Distribution Parameter On Geological Carbon Sequestration Estimates, Chu-Lin Cheng, Edmund Perfect, T. Edward Yu, Michael J. Gragg

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Cost estimates for geologic carbon sequestration (GCS) are vital for policy and decision makers evaluating carbon capture and storage strategies. Numerical models are often used in feasibility studies for the different stages of carbon injection and redistribution. Knowledge of the capillary pressure-saturation function for a selected storage rock unit is essential in applications used for simulating multiphase fluid flow and transport. However, the parameters describing these functions (e.g. the van Genuchten m pore size distribution parameter) are often not measured or neglected compared to other physical properties such as porosity and intrinsic permeability. In addition, the use of average …