Geology topics

Z. George Xue

Publications and source records attributed to Z. George Xue.

5 recordsLinked to original sources

USGS2025

Inundation processes, barrier island breaching, and structure impacts during Hurricane Michael (2018)

We demonstrate the increased ability to forecast hurricane impacts with a coupled numerical modeling system by simulating ocean waves, water levels, currents, sediment transport, and structural damage to predict inundation, coastal morphological change, and residential building impacts. The Coupled-Ocean-Atmosphere-Waves-Sediment-Transport (COAWST) modeling system is applied to simulate Hurricane Michael (category 5, 2018) that made landfall near Tyndall Air Force Base, FL, in the northern Gulf of America, causing severe devastation and flooding. Atmospheric forcings from the Coupled Ocean/Atmosphere Mesoscale Prediction System for Tropical Cyclones (COAMPS-TC) are used to drive the ocean and wave models on a series of nested grids. Results identify that coastal inundation at Mexico Beach is due to surge from winds and waves, supplemented by pulses of infragravity wave motions that propagate landward into the inundation region. Seed lines observed on interior building walls also demonstrate variable changes in water level. In addition, a machine learning model was applied to hindcast structure damages, caused mostly by waves and winds, with a 72% accuracy estimate of substantial damage in proximity of landfall. The storm also created a breach across Cape San Blas, the adjacent barrier spit, due to large surge and low dune elevations. Dune locations with vegetated land cover are shown to reduce wave-energy dissipation and reduce erosion, whereas locations without land cover had increased breaching potential. The breach occurred during the maximum ocean-side water level, and the delayed high water on the bay side allowed a pressure gradient to drive flow seaward and promote breach development.

Florida↗

USGS2025

Investigating hurricane-induced salt variation across the Land-Estuary-Ocean continuum using a dynamically coupled hydrological-ocean model

Salinity variations across the Land‐Estuary‐Ocean (LEO) continuum are critical for coastal ecosystems and impact the socioeconomic benefits to local communities. However, evaluating these variations is challenging due to the complex interactions of terrestrial and oceanic processes, including river discharge, winds, tides, sea level rise, and storms. This study incorporates a salinity module into a newly developed dynamically coupled hydrological‐ocean model on the COAWST platform, which is, to the best of our knowledge, the first process‐based modeling that achieves seamless two‐way land‐ocean water and salt exchanges across the LEO continuum, facilitating simulations of landward salt input and transport. Using Hurricane Florence (2018) as a case study, we examined how various physical processes influence salinity dynamics and freshwater plume development in the Cape Fear River Estuary, North Carolina. The model simulated saltwater intrusion into freshwater wetlands upstream of the estuary and demonstrated that salinity in the estuary was initially regulated by wind‐driven water level gradients, followed by a dominant influence from significant river runoff. In the coastal ocean, runoff created a large freshwater plume that moved westward, driven by the interplay between runoff, winds, and the estuary's geomorphology. The excellent performance of the coupling approach for salinity simulation underscores the importance of the seamless transport of water and salt at the land‐ocean interface. This study demonstrates that the coupled model is a valuable tool for representing saltwater intrusion, tracking coastal pollutants, and understanding water and material exchange across the LEO continuum.

North Carolina, South Carolina↗

USGS2024

Quantifying compound and nonlinear effects of hurricane-induced flooding using a dynamically coupled hydrological-ocean model

We recently developed a dynamically coupled hydrological-ocean modeling system that provides seamless coverage across the land-ocean continuum during hurricane-induced compound flooding. This study introduced a local inertial equation and a diagonal flow algorithm to the overland routing of the coupled system’s hydrology model (WRF-Hydro). Using Hurricane Florence (2018) as a test case, the performance of the coupled model was significantly improved, evidenced by its enhanced capability of capturing backwater and increased water level simulation accuracy and stability. With four model experiments, we present a framework to detangle, define, and quantify compound and nonlinear effects. The results revealed that the flood peaks in the lower Cape Fear River Basin and the coastal waters were contributed by inland flooding and storm surge, respectively. These two processes had comparable contributions to the flooding in the Cape Fear River Estuary. The compound effect was identified when the flood levels resulting from the combination of land and ocean processes surpassed those caused by an individual process alone. The compound effect during Hurricane Florence exhibited limited impact on flood peaks, primarily due to the time lag between the peaks of the storm surge and the inland flooding. In the period between the two peaks, the compound effect was salient and significantly impacted the magnitude and variation of the flood level. The nonlinear effect, defined as the difference between the compound flood level and the superposition of storm surge and inland flooding water levels, reduced flood levels in the river channels while increasing flood levels on the floodplain.

Water Resources Research↗

USGS2022

Largest recent impact craters on Mars: Orbital imaging and surface seismic co-investigation

Two 130+ meter diameter impact craters formed on Mars during the later half of 2021. These are the two largest fresh impact craters discovered by the Mars Reconnaissance Orbiter since operations started 16 years ago. The impacts created two of the largest seismic events (magnitudes greater than 4) recorded by InSight during its three year mission. The combination of orbital imagery and seismic ground motion enables the investigation of subsurface and atmospheric energy partitioning of the impact process on a planet with a thin atmosphere and the first direct test of Martian deep-interior seismic models with known event distances.The impact at 35°N excavated blocks of water ice, which is the lowest latitude ice has been directly observed on Mars.

Science↗

USGS2010

Ferromanganese crusts as archives of deep water Cd isotope compositions

The geochemistry of Cd in seawater has attracted significant attention owing to the nutrient-like properties of this element. Recent culturing studies have demonstrated that Cd is a biologically important trace metal that plays a role in the sequestration of inorganic carbon. This conclusion is supported by recent isotope data for Cd dissolved in seawater and incorporated in cultured phytoplankton. These results show that plankton features isotopically light Cd while Cd-depleted surface waters typically exhibit complimentary heavy Cd isotope compositions. Seawater samples from below 900 m depth display a uniform and intermediate isotope composition of ε 114/110 Cd = +3.3 ± 0.5. This study investigates whether ferromanganese (Fe-Mn) crusts are robust archives of deep water Cd isotope compositions. To this end, Cd isotope data were obtained for the recent growth surfaces of 15 Fe-Mn crusts from the Atlantic, Pacific, Indian, and Southern oceans and two USGS Fe-Mn reference nodules using double spike multiple collector inductively coupled plasma mass spectrometry. The Fe-Mn crusts yield a mean ε 114/110 Cd of +3.2 ± 0.4 (2 SE, n = 14). Data for all but one of the samples are identical, within the analytical uncertainty of ±1.1ε 114/110 Cd (2 SD), to the mean deep water Cd isotope value. This indicates that Fe-Mn crusts record seawater Cd isotope compositions without significant isotope fractionation. A single sample from the Southern Ocean exhibits a light Cd isotope composition of ε 114/110 Cd = 0.2 ± 1.1. The origin of this signature is unclear, but it may reflect variations in deep water Cd isotope compositions related to differences in surface water Cd utilization or long-term changes in seawater ε 114/110 Cd. The results suggest that time series analyses of Fe-Mn crusts may be utilized to study changes in marine Cd utilization.

Geochemistry, Geophysics, Geosystems↗