Preprints
Filtering by Subject: Physical Sciences and Mathematics
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), [...]
A prototype for a Multi-GNSS orbit combination
Published: 2020-08-20
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 [...]
Comment: The effect of post-conflict transition on deforestation in protected areas in Colombia
Published: 2020-08-20
Subjects: Environmental Sciences, Natural Resources and Conservation, Physical Sciences and Mathematics
A recent study on Colombian protected areas has found an increase in deforestation after ending armed conflict. The authors propose several drivers behind this trend and take their findings as proof of how these drivers specifically affect protected areas and render them particularly vulnerable to deforestation during post-conflict transition. However, after conducting an extended analysis of the [...]
Structure of the North Anatolian Fault Zone imaged via teleseismic scattering tomography
Published: 2020-08-20
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Information on fault zone structure is essential for our understanding of earthquake mechanics, continental deformation and our understanding of seismic hazard. We use the scattered seismic wavefield to study the subsurface structure of the North-Anatolian Fault Zone (NAFZ) in the region of the 1999 {\.I}zmit and D\"uzce rupture using data from an 18-month dense deployment of seismometers with a [...]
Quantitative estimates of average geomagnetic axial dipole dominance in deep geological time
Published: 2020-08-20
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
A defining characteristic of the recent geomagnetic field is its dominant axial dipole which provides its navigational utility and dictates the shape of the magnetosphere. Going back through time, much less is known about the degree of axial dipole dominance. Here we use a substantial and diverse set of 3D numerical dynamo simulations and recent observation-based field models to derive a power [...]
The 23 June 2020, Mw 7.4 La Crucecita, Oaxaca, Mexico earthquake and tsunami: A Rapid Response Field Survey during COVID-19 crisis
Published: 2020-08-18
Subjects: Earth Sciences, Other Earth Sciences, Physical Sciences and Mathematics
The 23 June 2020 La Crucecita earthquake occurred at 10:29 hr on the coast of Oaxaca in a Mw 7.4 megathrust event at 22.6 km depth, and triggered a tsunami recorded at Huatulco and Salina Cruz tide gauge stations and a DART off the coast of Mexico. Immediately after the earthquake, a rapid response effort was coordinated by members of the Tsunami and Paleoseismology Laboratory UNAM, despite the [...]
Citizen science reveals the population exposure to air pollution
Published: 2020-08-18
Subjects: Environmental Monitoring, Environmental Sciences, Physical Sciences and Mathematics
Air pollution remains a key environmental problem in an increasingly urbanized world. To quantify health impacts and support informed policies, the population exposure needs to be accurately monitored. However, the inherent spatial variability of air quality poses a tenacious challenge to this. While concentrations of traffic-related pollutants like nitrogen dioxide (NO2) are known to vary over [...]