Preprints
Filtering by Subject: Physical Sciences and Mathematics
Volcanic Lightning and Prebiotic Chemistry on the Early Earth
Published: 2022-09-16
Subjects: Chemistry, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Based on the paper by Pan et al., on the early Earth >4.2 Ga with limited exposed land areas, coupled with an ice covered ocean, lightning could have been rare. This presents a conundrum because lightning is considered to be an important energy source needed for the synthesis of prebiotic compounds required for the origin of life. Lightning occurrence during eruptions on wide spread volcanic [...]
Secular change of true polar wander over the past billion years
Published: 2022-09-15
Subjects: Physical Sciences and Mathematics
The rate of movement of Earth’s solid shell relative to its spin axis, or true polar wander, depends on variations in mantle convection and viscosity. We report paleomagnetic and geochronologic data from South China that constrain the rate of rapid true polar wander (>5° Myr-1) from 832–821 million years ago. Analysis of the paleomagnetic database demonstrates secular change of true polar wander [...]
The Equator Project
Published: 2022-09-10
Subjects: Education, Physical Sciences and Mathematics
Geography, Earth and Environmental Science (GEES) research will play a vital role in addressing the grand challenges of the 21st century, contributing to many of the UN sustainable development goals and the global energy transition. However, geoscience knowledge cannot be successfully applied to global problems that impact people from all walks of life unless the discipline itself is equitable. [...]
Lithogeochemistry in exploration for intrusion-hosted magmatic Ni-Cu-Co deposits
Published: 2022-09-09
Subjects: Physical Sciences and Mathematics
Magmatic Ni-Cu-Co-PGE deposits are notoriously difficult exploration targets owing to a lack of alteration haloes or other extended distal footprints. Success requires prediction of prospective terranes, followed by identification of suitable host intrusions and deposition sites within those intrusions. At the regional scale, potential ore-hosting magmas tend to have lithophile trace element [...]
Wavelet-based wavenumber spectral estimate of eddy kinetic energy: Idealized quasi-geostrophic flow
Published: 2022-09-09
Subjects: Physical Sciences and Mathematics
A wavelet-based method is re-introduced in an oceanographic and spectral context to estimate wavenumber spectrum and spectral flux of kinetic energy and enstrophy. We apply this to a numerical simulation of idealized, doubly-periodic quasi-geostrophic flows, i.e.~the flow is constrained by the Coriolis force and vertical stratification. The double periodicity allows for a straightforward Fourier [...]
Seasonal flow types of glaciers in Sermilik Fjord, Greenland, over 2016–2021
Published: 2022-09-08
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Greenland glaciers have three primary seasonal ice flow patterns, or “types”: terminus driven, runoff driven, and runoff adapting. To date, glacier types have been identified by analyzing flow at a single location near the terminus; information at all other locations is discarded. Here, we use principal component (PC) / empirical orthogonal function (EOF) analysis to decompose multi-year time [...]
Mineral dust aerosol impacts on global climate and climate change
Published: 2022-09-08
Subjects: Physical Sciences and Mathematics
Mineral dust aerosols impact Earth’s energy budget through interactions with radiation, clouds, atmospheric chemistry, the cryosphere and biogeochemistry. In this Review, we summarize these interactions and assess the resulting impacts of dust, and of changes in dust, on global climate and climate change. The total effect of dust interactions on Earth’s global energy budget—the dust effective [...]
Seasonal water storage in peat-forming bofedales sustains baseflow in the Andes
Published: 2022-09-08
Subjects: Physical Sciences and Mathematics
Humid puna Bofedales, or low gradient peat-forming wetlands, are a characteristic feature of the humid puna - a high elevation, seasonally dry grass- and shrub-land found throughout the Central Andes. Despite the importance of the humid puna in supplying water to downstream communities, and the inference that bofedales may play an important role, few studies have explored the hydrology of [...]
A Reproducible and Reusable Pipeline for Segmentation of Geoscientific Imagery
Published: 2022-09-07
Subjects: Education, Engineering, Life Sciences, Physical Sciences and Mathematics
Segmentation of Earth science imagery is an increasingly common task. Among modern techniques that use Deep Learning, the UNet architecture has been shown to be a reliable for segmenting a range of imagery. We developed software - Segmentation Gym - to implement a data-model pipeline for segmentation of scientific imagery using a family of UNet models. With an existing set of imagery and labels, [...]
Variational inference of ice shelf rheology with physics-informed machine learning
Published: 2022-09-06
Subjects: Earth Sciences, Glaciology, Other Mathematics, Other Statistics and Probability, Physical Sciences and Mathematics
Floating ice shelves that fringe the coast of Antarctica resist the flow of grounded ice into the ocean. One of the key factors governing the amount of flow-resistance provided by an ice shelf is the rigidity of the ice that constitutes it. Ice rigidity is highly heterogeneous and must be calibrated from spatially-continuous surface observations assimilated into an ice flow model. Moreover, [...]
Source location and wavefield characterization of river-induced seismic tremor
Published: 2022-09-06
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
River-induced seismic signal (tremor) recorded by deploying seismic stations close to the river can be used to obtain the flow characteristics of rivers indirectly. This task becomes challenging when the tremor is contaminated by strong cultural noise. We conducted an experiment next to Avoca River, County Wicklow, Ireland. We locate and characterize the river-induced tremor by combining the [...]
Locating Flowing Conduits in Karst Using Amplitude-based Passive Seismic Location Method
Published: 2022-09-06
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The aim of this study is to develop methods for directly detecting energetic groundwater flow in sub-surface conduits through passive seismic applications, by detecting the small ground vibrations (seismic microtremor) that flowing water in the sub-surface may generate. This is in contrast to the current ‘traditional’ approach of attempting to actively image the conduits using geophysical and [...]
A mass budget and box model of global plastics cycling, degradation and dispersal in the land-ocean-atmosphere system
Published: 2022-09-02
Subjects: Physical Sciences and Mathematics
Since 1950 humans have introduced 8300 teragrams (Tg, 1012 grams, millions of metric tons) of plastic polymers into the Earth’s surface environment. Accounting for the dispersal and fate of produced plastics and fragmented microplastics in the environment has been challenging. Recent studies have fueled debate of the global river budget for plastic transport to oceans, the sinking and beaching of [...]
A 1.2 Billion Pixel Human-Labeled Dataset for Data-Driven Classification of Coastal Environments
Published: 2022-09-01
Subjects: Physical Sciences and Mathematics
The world’s coastlines are spatially highly variable, coupled-human-natural systems that comprise a nested hierarchy of component landforms, ecosystems, and human interventions, each interacting over a range of space and time scales. Understanding and predicting coastline dynamics necessitates frequent observation from imaging sensors on remote sensing platforms. Machine Learning models that [...]
Accumulation of radiocarbon in ancient terrestrial landscapes: A small but significant input of unknown origin
Published: 2022-09-01
Subjects: Physical Sciences and Mathematics
The persistence of soil organic carbon (C) in soil, defined as the mean residence time of organic C compounds in soils, is a critical measure for understanding the capacity of terrestrial ecosystems to regulate biogeochemical cycles. The persistence of organic carbon in soil is most often considered at timescales ranging from tens to thousands of years, but the study of organic C in paleosols [...]