Preprints
Filtering by Subject: Earth Sciences
A Physics-Based Decorrelation Phase CovarianceModel for Noise Reduction in UnwrappedInterferometric Phase Stacks
Published: 2020-10-23
Subjects: Earth Sciences, Statistics and Probability
The accuracy of geophysical parameter estimation made with Interferometric Synthetic Aperture Radar (InSAR) time-series techniques can be improved with rapidly increasing available data volumes, and with the development of noise covariance matrices applicable to joint analysis of networks of interferograms. Here we present a physics-based decorrelation phase covariance model and discuss [...]
Testing the effect of bioturbation and species abundance upon discrete-depth individual foraminifera analysis
Published: 2020-10-22
Subjects: Earth Sciences, Geology
We use a single foraminifera enabled, holistic hydroclimate-to-sediment transient modelling approach to fundamentally evaluate the efficacy of discrete-depth individual foraminifera analysis (IFA) for reconstructing past sea surface temperature (SST) variability from deep-sea sediment archives, a method that has been used for, amongst other applications, reconstructing El Niño Southern [...]
Controls on denudation along the East Australian continental margin
Published: 2020-10-22
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
We report a comprehensive inventory of Be-10-based basin-wide denudation rates (n=160) and Al-26/Be-10 ratios (n=67) from 48 drainage basins along a 3,000 km stretch of the East Australian passive continental margin. We provide data from both basins draining east of the continental divide (n=37) and discharging into the Tasman and Coral Seas, and from basins draining to the west as part of the [...]
Linking elastic and electrical properties of rocks using cross-property DEM
Published: 2020-10-22
Subjects: Earth Sciences, Engineering Science and Materials, Geophysics and Seismology, Materials Science and Engineering, Physical Sciences and Mathematics
Joint electrical-elastic rock physics modelling can be instrumental in lowering uncertainty in subsurface reservoir characterisation. Typical electrical-elastic cross-property models, however, are empirical or require an intermediate step of porosity estimation to link a rock's electrical and elastic moduli, which can be error-prone away from well controls. Another outstanding issue in [...]
Pangeo Benchmarking Analysis: Object Storage vs. POSIX File System
Published: 2020-10-21
Subjects: Computer Sciences, Earth Sciences, Physical Sciences and Mathematics
Pangeo is a community of scientists and software developers collaborating to enable Big Data Geoscience analysis interactively in the public cloud and on high-performance computing (HPC) systems. At the core of the Pangeo software stack is (1) Xarray, which adds labels to metadata such as dimensions, coordinates and attributes for raw array-oriented data, (2) Dask, which provides parallel [...]
Relative humidity gradients as a key constraint on terrestrial water and energy fluxes
Published: 2020-10-21
Subjects: Earth Sciences, Physical Sciences and Mathematics
Earth’s climate and water cycle are highly dependent on the latent heat flux (LE) associated with terrestrial evapotranspiration. While the widely-used Penman-Monteith LE model is useful to explore vegetative controls on LE, land-atmosphere interactions are difficult to interpret due to the complex role of biological controls on underlying physical processes. Here, we present a novel LE model [...]
High-Pressure Deformation of Iron–Nickel–Silicon Alloys and Implications for Earth’s Inner Core
Published: 2020-10-21
Subjects: Earth Sciences, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics
Earth’s inner core exhibits strong seismic anisotropy, often attributed to the alignment of hexagonal close-packed iron (hcp-Fe) alloy crystallites with the Earth’s poles. How this alignment developed depends on material properties of the alloy and is important to our understanding of the core’s crystallization history and active geodynamical forcing. Previous studies suggested that hcp-Fe is [...]
The global melt inclusion C/Ba array: mantle variability, melting process, or degassing?
Published: 2020-10-21
Subjects: Earth Sciences, Geochemistry
The Earth’s mantle holds more carbon than its oceans, atmosphere and continents combined, yet the distribution of carbon within the mantle remains uncertain. Our best constraints on the distribution of carbon within the upper mantle are derived from the carbon-trace element systematics of ultra-depleted glasses and melt inclusions from mid-ocean ridge basalts. However, carbon-trace element [...]
Dynamics of core-mantle separation: influence of viscosity contrast and metal/silicate partition coefficients on the chemical equilibrium
Published: 2020-10-21
Subjects: Earth Sciences, Geochemistry, Geophysics and Seismology, Physical Sciences and Mathematics
The composition of the Earth's core and mantle is set by the chemical equilibrium between metals and silicates during core/mantle segregation. The metallic core separated from the mantle by gravitational descent in the form of diapirs in a magma ocean, and therefore the dynamics of the diapir's downward movement has an influence on the chemical equilibrium. In this study, we characterize the [...]
Amphibole Control on Copper Systematics in Arcs: Insights from the Analysis of Global Datasets
Published: 2020-10-21
Subjects: Earth Sciences, Geochemistry, Geology, Volcanology
Copper, sourced from porphyry deposits formed in arc settings, is a critical resource, and is primarily sourced from magmas. However, the processes that shape the copper contents of arc magmas are up for debate. Existing models place emphasis on different petrological agents that explain large-scale trends in copper systematics. Previous studies have noted the 'Cu paradox,' where the magmas with [...]
Inverse analysis to reconstruct hydraulic conditions of non-steady turbidity currents: Application to an ancient turbidite of the Kiyosumi Formation of the Awa Group, Boso Peninsula, central Japan
Published: 2020-10-21
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology
This study proposes a new method of inverse analysis from ancient turbidites to the non-steady turbidity currents with consideration of multiple grain-size classes. The forward model employed in this study is based on the shallow water equation, and the initial condition of flows are assumed to be the lock-exchange type condition. To obtain a solution of the inverse problem, this study employed [...]
Grain Size and Beach Face Slope on Paraglacial Beaches of New England, USA
Published: 2020-10-21
Subjects: Earth Sciences, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology
Approximately 100 paired summer and winter transects of beach face slope and intertidal grain size were examined from 18 separate beaches in southern New England that span meso- and micro- tidal regimes. Paraglacial materials provide the principal local sediment source to beaches in this region and grain-size distribution of beaches corresponds to adjacent surficial geology. Stratified glacial [...]
Uncertainties in Projected Rainfall over Brazil: The Role of Climate Model, Bias Correction and Emission Scenario
Published: 2020-09-01
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
The aim of this study is to answer four main questions: How well the Eta regional climate model simulates past precipitation over Brazil? What is the impact of bias correction on the reduction of model’s biases? What is the contribution of climate models, bias correction and emission scenarios to the total uncertainty of projected precipitation? And finally, what is the projected change in [...]
Mercury stable isotopes constrain atmospheric sources to the Ocean
Published: 2020-08-28
Subjects: Earth Sciences, Environmental Sciences, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Human exposure to toxic mercury (Hg) is dominated by the consumption of seafood1,2. Earth system models suggest that Hg in marine ecosystems is supplied by atmospheric wet and dry Hg(II) deposition, with a 3 times smaller contribution from gaseous Hg(0) uptake3,4. Observations of marine Hg(II) deposition and Hg(0) gas exchange are sparse however5, leaving the suggested importance of Hg(II) [...]
An analytical solution to the Navier–Stokes equation for incompressible flow around a solid sphere
Published: 2020-08-25
Subjects: Applied Mathematics, Earth Sciences, Engineering, Fluid Dynamics, Mechanical Engineering, Other Mechanical Engineering, Partial Differential Equations, Physical Sciences and Mathematics, Physics, Special Functions
This paper is concerned with obtaining a formulation for the flow past a sphere in a viscous and incompressible fluid, building upon previously obtained well-known solutions that were limited to small Reynolds numbers. Using a method based on a summation of separation of variables, we develop a general analytical solution to the Navier--Stokes equation for the special case of axially symmetric [...]