Preprints
There are 4725 Preprints listed.
Emergent self-similarity and scaling properties of fractal intra-Urban Heat Islets for diverse global cities
Published: 2019-09-02
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Physical Sciences and Mathematics, Statistics and Probability
Urban areas experience elevated temperatures due to the Urban Heat Island (UHI) effect. However, temperatures within cities vary considerably and their spatial heterogeneity is not well characterized. Here, we use Land Surface Temperature (LST) of 78 global cities to show that the Surface UHI (SUHI) is fractal. We use percentile-based thermal thresholds to identify heat clusters emerging within [...]
Comparing Aggradation, Superelevation, and Avulsion Frequency of Submarine and Fluvial Channels
Published: 2019-08-30
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
IN REVIEW IN "FRONTIERS IN EARTH SCIENCE" (30 Aug 2019). Constraining the avulsion dynamics of rivers and submarine channels is essential for predicting the distribution and architecture of sediment, organic matter and pollutants in alluvial, deltaic, and submarine settings. Submarine channels are well known to be more aggradational than rivers, and aggradation of the channel, levee, and [...]
Controls on variations in minibasin geometries: Lower Congo Basin, offshore Angola
Published: 2019-08-30
Subjects: Earth Sciences, Geology, Other Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
In passive margin salt basins, the distinct tectonic domains of thin-skinned extension and contraction exert important controls on the geometry and evolution of minibasins. In this study, we use a semi-regional 3D seismic dataset from the Lower Congo Basin to investigate the spatial and temporal evolution of a network of salt-related minibasins and intervening salt walls and diapirs during [...]
Subduction history reveals Cretaceous slab superflux as a possible cause for the mid-Cretaceous plume pulse and superswell events
Published: 2019-08-29
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Subduction is a fundamental mechanism of material exchange between the planetary interior and the surface. Despite its significance, our current understanding of fluctuating subducting plate area and slab volume flux has been limited to a range of proxy estimates. Here we present a new detailed quantification of subduction zone parameters from the Late Triassic to present day (230 – 0 Ma). We use [...]
Anatomy of exhumed river-channel belts: Bedform- to belt-scale kinematics of the Ruby Ranch Member, Cretaceous Cedar Mountain Formation, Utah, USA
Published: 2019-08-29
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Many published interpretations of ancient fluvial systems have relied on observations of extensive outcrops of thick successions. This paper, in contrast, demonstrates that a regional understanding of paleoriver kinematics, depositional setting, and sedimentation rates can be interpreted from local sedimentological measurements of bedform and barform strata. Dune and bar strata, channel planform [...]
Accounting for training data error in machine learning applied to Earth observations
Published: 2019-08-29
Subjects: Earth Sciences, Engineering, Environmental Monitoring, Environmental Sciences, Life Sciences, Physical Sciences and Mathematics
Remote sensing, or Earth Observation (EO), is increasingly used to understand Earth system dynamics and create continuous and categorical maps of biophysical properties and land cover, especially based on recent advances in machine learning (ML). ML models typically require large, spatially explicit training datasets to make accurate predictions. Training data (TD) are typically generated by [...]
Speeding up PPP ambiguity resolution using triple-frequency GPS/BeiDou/Galileo/QZSS data
Published: 2019-08-29
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Engineering, Navigation, Guidance, Control and Dynamics
Precise point positioning (PPP) has been suffering from slow convergences to ambiguity-fixed solutions. It is expected that this situation can be relieved or even resolved using triple-frequency GNSS data. We therefore attempt an approach where uncombined triple-frequency GPS/BeiDou/Galileo/QZSS (Quasi-zenith satellite system) data are injected into PPP, whereas their raw ambiguities are mapped [...]
Observed and modelled tidal bar sedimentology reveals preservation bias against mud in estuarine stratigraphy
Published: 2019-08-29
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
Mud plays a pivotal role in estuarine ecology and morphology. However, field data on the lateral and vertical depositional record of mud is rare. Furthermore, numerical morphodynamic models often ignore mud due to long computational times and implications of mixed depositional processes. This study aims to understand the spatial distribution, formative conditions, and preservation of mud deposits [...]
Considering the role of adaptive evolution in models of the ocean and climate system
Published: 2019-08-29
Subjects: Earth Sciences, Ecology and Evolutionary Biology, Life Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Numerical models have been highly successful in simulating global carbon and nutrient cycles in today’s ocean, together with observed spatial and temporal patterns of chlorophyll and plankton biomass at the surface. With this success has come some confidence in projecting the century-scale response to continuing anthropogenic warming. There is also increasing interest in using such models to [...]
Bluecap: A Geospatial Model to Assess Regional Economic-Viability for Mineral Resource Development
Published: 2019-08-29
Subjects: Engineering, Mining Engineering
Frontier mineral exploration is often exclusively focused on assessing geological potential without consideration for the economic viability of resource development. This strategy may overlook potentially prosperous zones for more geologically-favoured but financially-disadvantageous regions, or conversely, may introduce implicit biases against potential developments without due regard to [...]
Solar signals in observation indeed implied enhanced predictability since 1977
Published: 2019-08-27
Subjects: Climate, Meteorology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
This is a Correspondence submitted to Nature GeoScience following the undermentioned paper: Gabriel Chiodo, Jessica Oehrlein, Lorenzo M. Polvani, John C. Fyfe & Anne K. Smith, Insignificant influence of 11-year solar cycle on the North Atlantic Oscillation, Nature Geoscience, volume 12, pages 94–99 (2019). It is a non-peer reviewed preprint.
Fracture Mechanical Properties of Damaged and Hydrothermally Altered Rocks, Dixie Valley - Stillwater Fault Zone, Nevada, USA
Published: 2019-08-27
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
An edited version of this paper was published by AGU. Copyright (2019) American Geophysical Union. Callahan, O. A., Eichhubl, P., Olson, J. E., & Davatzes, N. C. (2019). Fracture Mechanical Properties of Damaged and Hydrothermally Altered Rocks, Dixie Valley‐Stillwater Fault Zone, Nevada, USA. Journal of Geophysical Research: Solid Earth, 124(4), 4069-4090. [...]
Towards Improved Predictions in Ungauged Basins: Exploiting the Power of Machine Learning
Published: 2019-08-26
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
Long Short-Term Memory (LSTM) networks offer unprecedented accuracy for prediction in ungauged basins. We trained and tested an LSTM on the CAMELS basins (approximately 30 years of daily rainfall/runoff data from 531 catchments in the US of sizes ranging from 4 km² to 2,000 km²) using k-fold validation, so that predictions were made in basins that supplied no training data. This effectively [...]
Imbibition in porous media: correlations of displacement events with pore-throat geometry and the identification of a new type of pore snap-off
Published: 2019-08-23
Subjects: Chemical Engineering, Civil and Environmental Engineering, Complex Fluids, Dynamics and Dynamical Systems, Engineering, Engineering Science and Materials, Environmental Engineering, Materials Science and Engineering, Mechanics of Materials, Petroleum Engineering, Transport Phenomena
The displacement of a non-wetting fluid by a wetting fluid in porous media, called imbibition, is important in many natural and industrial processes. During imbibition, the wetting fluid invades the pore space through a series of competitions between piston-like displacement, film and corner flow, snap-off, pore bypassing and trapping. Our understanding of these fundamental pore-scale [...]
Cohesive-Zone Effects in Hydraulic Fracture Propagation
Published: 2019-08-22
Subjects: Earth Sciences, Engineering, Engineering Mechanics, Engineering Science and Materials, Environmental Sciences, Geophysics and Seismology, Oil, Gas, and Energy, Physical Sciences and Mathematics
Hydraulic fracture presents an interesting case of crack elasticity and fracture propagation non-linearly coupled to fluid flow. Hydraulic fracture (HF) is often modeled using the Linear Elastic Fracture Mechan- ics (LEFM), which assumes that the damaged zone associated with the rock breakage near the advancing fracture front is small compared to the lengthscales of other physical processes [...]