Preprints

There are 15 Preprints listed.

A continental-scale assessment of density, size, distribution, and historical trends of Australian farm dams

Martino E. Malerba, Nicholas Wright, Peter Macreadie

Published: 2020-09-02
Subjects: Environmental Monitoring, Environmental Sciences, Natural Resources and Conservation, Natural Resources Management and Policy, Physical Sciences and Mathematics, Water Resource Management

Australia is the second driest continent on Earth and freshwater is, therefore, a critical policy concern. Farm dams are ubiquitous and drive AU$17.7 billion of agricultural value, yet there has never been a formal census of Australian dams. In this study, we present a continental-scale assessment on density, distribution, and historical trends of farm dams in each State and Territory of [...]

What does the NDVI really tell us about crops? Insight from proximal spectral field sensors

Jon Atherton, Chao Zhang, jaakko Oivukkamäki, Liisa Kulmala, Shan Xu, Teemu Hakala, Eija Honkavaara, Alasdair MacArthur, Albert Porcar-Castell

Published: 2020-09-02
Subjects: Environmental Monitoring, Environmental Sciences, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics

The use of remote sensing in agriculture is expanding due to innovation in sensors and platforms. Drones, high resolution instruments on CubeSats, and robot mounted proximal phenotyping sensors all feature in this drive. Common threads include a focus on high spatial and spectral resolution coupled with the use of machine learning methods for relating observations to crop parameters. As the [...]

Structure and age relationship of joint sets on the Lilstock Benches, UK, based on mapping a full resolution UAV-based image

Martijn Passchier, Janos Urai, Cees Passchier

Published: 2020-09-01
Subjects: Environmental Sciences, Other Environmental Sciences, Physical Sciences and Mathematics

Outcrop studies of fracture networks are important to understand such networks in the subsurface, but complete maps of all fractures in large outcrops are rare due to limitations of outcrop and image resolution. We present the first full-resolution UAV-based, Gigapixel dataset and DEM of the wave-cut Lilstock Benches in the southern Bristol Channel basin, a classic outcrop of layer-bound fracture [...]

Mercury stable isotope composition of seawater suggests important net gaseous elemental mercury uptake

Martin Jiskra, Lars-Eric Heimburger-Boavida, Marie-Maelle Desgranges, Mariia Petrova, Aurelie Dufour, Beatriz Ferreira-Araujo, Jeremy Masbou, Jerome Chmeleff, Melilotus Thyssen, David Point

Published: 2020-08-29
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 seafood. Earth system models suggest that Hg in marine ecosystems is supplied by Hg(II) deposition, with a 3x smaller contribution from gaseous Hg(0) uptake, and that photochemical reduction of marine Hg(II) drives important Hg(0) evasion to the atmosphere. Observations of marine Hg(II) deposition and gas exchange are sparse [...]

An analytical solution to the Navier–Stokes equation for incompressible flow around a solid sphere

Ahmad Talaei, Timothy J. Garrett

Published: 2020-08-26
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 [...]

The composition and weathering of the continents over geologic time

Alex Lipp, Oliver Shorttle, Erik Sperling, Jochen J Brocks, Devon Cole, Peter Crockford, Lucas Del Mouro, Keith Dewing, Stephen Q Dornbos, Joseph F. Emmings

Published: 2020-08-22
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics

The composition of continental crust records a history of construction by tectonics and destruction by physical and chemical erosion. Quantitative constraints on how both igneous addition and chemical weathering have modified the continents bulk composition are essential for understanding the evolution of geodynamics and climate. We have extracted temporal trends in sediments protolith [...]

GARPOS: analysis software for the GNSS-A seafloor positioning with simultaneous estimation of sound speed structure

Shun-ichi Watanabe, Tadashi Ishikawa, Yusuke Yokota, Yuto Nakamura

Published: 2020-08-22
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

Global Navigation Satellite System – Acoustic ranging combined seafloor geodetic technique (GNSS-A) has extended the geodetic observation network into the ocean. The key issue for analyzing the GNSS-A data is how to correct the effect of sound speed variation in the seawater. We constructed a generalized observation equation and developed a method to directly extract the gradient sound speed [...]

Computing single-particle flotation kinetics using automated mineralogy data and machine learning

Lucas Pereira, Max Frenzel, Duong Huu Hoang, Raimon Tolosana-Delgado, Martin Rudolph, Jens Gutzmer

Published: 2020-08-21
Subjects: Earth Sciences, Engineering, Geology, Mining Engineering, Physical Sciences and Mathematics

Flotation kinetic studies are essential for predicting, understanding, and optimizing the selective recovery of an ore through flotation. Recently, much effort has been put into incorporating intrinsic ore properties in the understanding of their flotation behavior. Particle-based characterization systems (e.g. automated mineralogy) drove much of this development. However, the currently available [...]

Quantification of non-linear multiphase flow in porous media

Yihuai Zhang, Branko Bijeljic, Ying Gao, Qingyang Lin, Martin J. Blunt

Published: 2020-08-21
Subjects: Earth Sciences, Engineering, Hydrology, Life Sciences, Medicine and Health Sciences, Mineral Physics, Physical Sciences and Mathematics

We measure the pressure difference during two-phase flow across a sandstone sample for a range of injection rates and fractional flows of water, the wetting phase, during an imbibition experiment. We quantify the onset of a transition from a linear relationship between flow rate and pressure gradient to a non-linear power-law dependence. We show that the transition from linear (Darcy) to [...]

Identifying and correcting the World War 2 warm anomaly in sea surface temperature measurements

DUO CHAN, Peter Huybers

Published: 2020-08-21
Subjects: Climate, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

Most foregoing estimates of historical sea surface temperature (SST) feature warmer global-average SSTs during World War 2 well in excess of climate-model predictions. This warm anomaly, referred to as the WW2WA, was hypothesized to arise from incomplete corrections of biases associated with rapid changes in measurement instruments and protocols. Using linear mixed-effects methods we confirm [...]

Correcting 19th and 20th century sea surface temperatures improves simulations of Atlantic hurricane activity

DUO CHAN, Gabriel A. Vecchi, Wenchang Yang, Peter Huybers

Published: 2020-08-21
Subjects: Atmospheric Sciences, Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

Changes in the statistics of North Atlantic hurricanes are known to depend upon the pattern of tropical sea surface temperatures (SSTs). Dynamical and statistical models are key tools to predict future hurricane activity, with our confidence in this application rooted in the models’ ability to skillfully reproduce hurricane variations over the past 30-40 years, when satellite data allows [...]

An Integrated Flood Risk Assessment and Mitigation Framework: Middle Cedar River Basin Case Study

Enes Yildirim, Ibrahim Demir

Published: 2020-08-21
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Physical Sciences and Mathematics, Water Resource Management

Property buyout is one of the most frequently preferred flood mitigation applications by decision-makers for long-term risk reduction. Due to its high-level funding requirements as a mitigation solution, it requires extensive benefits and costs analysis for the selected region. Many communities in the State of Iowa experienced flood events (i.e. 1993, 2008, 2014, 2019) which resulted in a heavy [...]

A unifying basis for the interplay of stress and chemical processes in the Earth: support from diverse experiments

John Wheeler

Published: 2020-08-21
Subjects: Earth Sciences, Physical Sciences and Mathematics

The Earth is under stress on all scales from individual grains to the entire crust and mantle. Mineral reactions, including pressure solution and diffusion creep, occur in that context. Whilst the effect of pressure on mineral reactions is understood through well established thermodynamics, the effect of stress on mineral reactions is not. Here I show that a particular equation linking stress and [...]

The Ediacaran Grenville dykes (SE Canada) reveal the weakest sustained palaeomagnetic field on record.

Daniele Thallner, Andrew Biggin, Henry Halls

Published: 2020-08-21
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

Long-term variations of the geomagnetic field, observed in the palaeomagnetic record, have the potential to shed much light on the evolution of Earth’s deep interior. With a geomagnetic field characterised by anomalous directions and ultra-low intensities, the Ediacaran period (635-541 Ma) is a time of special interest. Steep and shallow directions, leading to virtual geomagnetic poles (VGPs), [...]

A prototype for a Multi-GNSS orbit combination

Pierre Sakic, Gustavo Mansur, Benjamin Männel

Published: 2020-08-21
Subjects: Astrophysics and Astronomy, Earth Sciences, Other Astrophysics and Astronomy, Other Earth Sciences, Physical Sciences and Mathematics

Since 1994, the International GNSS Service (IGS) provides a combination of orbit and clock offset products from its different Analysis Centers. These products are used as input by many software for countless scientific and/or operational applications. They can also be used as an independent reference for benchmark experiments. Nevertheless, those products include GPS-only data, despite the fact [...]

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