Preprints
There are 4725 Preprints listed.
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 [...]
A continental-scale assessment of density, size, distribution, and historical trends of Australian farm dams
Published: 2020-09-01
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
Published: 2020-09-01
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
Published: 2020-08-31
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 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 [...]
The composition and weathering of the continents over geologic time
Published: 2020-08-21
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
Published: 2020-08-21
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
Published: 2020-08-20
Subjects: Earth Sciences, Engineering, Geology, Mining Engineering, Physical Sciences and Mathematics
Studies of flotation kinetics are essential for understanding, predicting, and optimizing the selective recovery of minerals and metals through flotation. Recently, much effort has been made to use intrinsic ore properties to model flotation behavior. Particle-based characterization methods, e.g. SEM-based image analysis, has enabled much of this development. However, currently available methods [...]
Quantification of non-linear multiphase flow in porous media
Published: 2020-08-20
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
Published: 2020-08-20
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
Published: 2020-08-20
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
Published: 2020-08-20
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
Published: 2020-08-20
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.
Published: 2020-08-20
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), [...]