Filtering by Subject: Earth Sciences

Tree cover change proves stability and instability in tropical ecosystems

Chandrakant Singh, Ruud van der Ent, Lan Wang-Erlandsson, et al.

Published: 2021-09-17
Subjects: Earth Sciences, Ecology and Evolutionary Biology, Forest Biology, Hydrology, Remote Sensing

Terrestrial tropical ecosystems’ resilience is determined predominantly based on space-for-time substitution, which assumes that the current ‘static’ frequency distribution of ecosystems’ tree cover structure across space also holds across time. However, dynamic and temporal aspects are increasingly important to explicitly account for under ongoing rapid climate change. Here, we empirically study [...]

Shear-wave Anisotropy in the Earth’s Inner Core

Sheng Wang, Hrvoje Tkalčić

Published: 2021-09-17
Subjects: Earth Sciences, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics

Earth’s inner core anisotropy is widely used to infer the deep Earth's evolution and present dynamics. Many compressional-wave anisotropy models have been proposed based on seismological observations. In contrast, inner-core shear-wave (J-wave) anisotropy – on a par with the compressional-wave anisotropy – has been elusive. Here we present a new class of the J-wave anisotropy observations [...]

The Impact of Neglecting Climate Change and Variability on ERCOT’s Forecasts of Electricity Demand in Texas

Jangho Lee, Andrew E Dessler

Published: 2021-09-16
Subjects: Earth Sciences, Environmental Sciences, Environmental Studies, Oceanography and Atmospheric Sciences and Meteorology, Risk Analysis

The Electric Reliability Council of Texas (ERCOT) manages the electric power across most of Texas. They make short-term assessments of electricity demand based on historical weather over the last decade or two, thereby ignoring the effects of climate change and the possibility of weather variability outside of the recent historical range. In this paper, we develop an empirical methodology to [...]

Acquisition of Data for Building Photogrammetric Virtual Outcrop Models for the Geosciences using Remotely Piloted Vehicles (RPVs)

John A. Howell, Magda Chmielewska, Conor Lewis, et al.

Published: 2021-09-14
Subjects: Earth Sciences, Environmental Sciences

Over the past five years the use of 3D models in the Earth Sciences has become ubiquitous. These models, termed Virtual outcrops, are most commonly generated using Structure from Motion (SfM) photogrammetry, an image-based modelling method that has achieved widespread uptake and utilization. Data for these models is commonly acquired using remotely piloted aerial vehicles (RPVs), commonly called [...]

Scum of the Earth: a hypothesis for prebiotic multi-compartmentalised environments}

Craig Robert Walton, Oliver Shorttle

Published: 2021-09-14
Subjects: Biochemistry, Biophysics, and Structural Biology, Earth Sciences, Planetary Sciences

Compartmentalisation by bioenergetic membranes is a universal feature of life. The eventual compartmentalisation of prebiotic systems is therefore often argued to comprise a key step during the origin of life. Compartments may have been active participants in prebiotic chemistry, concentrating and spatially organising key reactants. However, most prebiotically plausible compartments are leaky or [...]

Three-dimensional fluid-driven stable frictional ruptures

Alexis Sáez, Brice Lecampion, Pathikrit Bhattacharya, et al.

Published: 2021-09-13
Subjects: Earth Sciences, Engineering, Environmental Sciences, Geophysics and Seismology, Oil, Gas, and Energy, Physical Sciences and Mathematics, Physics

We investigate the quasi-static growth of a fluid-driven frictional shear crack that propagates in mixed mode (II+III) on a planar fault interface that separates two identical half-spaces of a three-dimensional solid. The fault interface is characterized by a shear strength equal to the product of a constant friction coefficient and the local effective normal stress. Fluid is injected into the [...]

Flow-dependent and dynamical systems analyses of predictability of the Pacific-North American summertime circulation

Ebrahim Nabizadeh, Sandro W Lubis, Pedram Hassanzadeh

Published: 2021-09-10
Subjects: Atmospheric Sciences, Dynamical Systems, Earth Sciences

Forecast skills of numerical weather prediction (NWP) models and intrinsic predictability can be flow-dependent, e.g., different among weather regimes. Here, we have examined the predictability of distinct Pacific-North American weather regimes in June-September. Four weather regimes are identified using a self-organizing map analysis of daily 500-hPa geopotential height anomalies, and are [...]

The influence of layer and voxel geological modelling strategy on groundwater modelling results

Trine Enemark, Lærke Andersen, Anne-Sophie Høyer, et al.

Published: 2021-09-09
Subjects: Earth Sciences, Water Resource Management

Reliable groundwater model predictions are dependent on representative models of the geological environment, which can be modelled using several different techniques. In order to inform the choice of the geological modelling technique, the differences between a layer modelling approach and a voxel modelling approach were analyzed. The layer model consist of stratigraphically ordered surfaces, [...]

Tropical Cyclones Affecting Tokyo and Changing Storm Surge Hazard since 1980

Md. Rezuanul Islam, Masaki Satoh, Hiroshi Takagi

Published: 2021-09-08
Subjects: Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Risk Analysis

This study investigated tidal records and landfall tropical cyclone (TC) best tracks in Japan from 1980 to 2019 to determine changes in storm surge heights in coastal regions of eastern Japan, including Tokyo. The results indicate that annual mean storm surge heights have increased in the last 20 years (2000–2019) compared to those in 1980–1999, and that these changes are noteworthy, particularly [...]

Thrusts control the thermal maturity of accreted sediments

Utsav Mannu, David Fernández-Blanco, Ayumu Miyakawa, et al.

Published: 2021-09-08
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure

Thermal maturity assessments of hydrocarbon-generation potential and thermal history rarely consider how structures developing during subduction influence the trajectories of accreted sediments. Our thermomechanical models of subduction support that thrusts evolving under variable sedimentation rates and décollement strengths fundamentally influence the trajectory, temperature, and thermal [...]

The ‘europium anomaly’ in plants: facts and fiction

Olivier Pourret, Antony van der Ent, Andrew Hursthouse, et al.

Published: 2021-09-08
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Life Sciences, Plant Sciences

Rare earth elements (REEs) and normalized REE pattern determined in plant and soil samples represent powerful tools to trace biogeochemical processes during weathering, soil genesis and processes in the rhizosphere, and thus publications reporting rare earth elements and normalized REE pattern in soil systems and plants are increasing rapidly. Generally, a normalized REE pattern allow for the [...]

Higher Long-Term Soil Moisture Increases Organic Carbon Accrual Through Microbial Conversion of Organic Inputs

Itamar Shabtai, Srabani Das, Thiago Inagaki, et al.

Published: 2021-09-08
Subjects: Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics

High long-term soil moisture may either stimulate or inhibit soil organic carbon (SOC) losses through changes to mineral and chemical composition, and resultant organo-mineral interactions. Yet, the trade-off between mineralization and accrual of SOC under long-term variation in unsaturated soil moisture remains an uncertainty. In this study, we tested the underexplored relationships between [...]

Drone-mounted GPR surveying: flight-height considerations for diffraction-based velocity analysis

Adam Booth, Tiffany Koylass

Published: 2021-09-06
Subjects: Earth Sciences, Geophysics and Seismology, Other Earth Sciences

Recent studies highlight the potential of the drone platform for ground penetrating radar (GPR) surveying. Most guidance for optimising drone flight-heights is based on maximising the image quality of target responses, but no study yet considers the impact on diffraction travel-times. Strong GPR velocity contrasts across the air-ground interface introduce significant refraction effects that [...]

Lowermost mantle shear-velocity structure from hierarchical trans-dimensional Bayesian tomography

Sima Mousavi, Hrvoje Tkalčić, Rhys Hawkins, et al.

Published: 2021-09-05
Subjects: Earth Sciences, Physical Sciences and Mathematics

The core-mantle boundary (CMB) is the most extreme boundary within the Earth where the liquid, iron-rich outer core interacts with the rocky, silicate mantle. The nature of the lowermost mantle atop the CMB, and its role in mantle dynamics, is not completely understood. Various regional studies have documented significant heterogeneities at different spatial scales. While there is a consensus on [...]

CCREM: New reference Earth model from the global coda-correlation wavefield

Xiaolong Ma, Hrvoje Tkalčić

Published: 2021-09-02
Subjects: Earth Sciences, Physical Sciences and Mathematics

The existing Earth reference models have provided an excellent one-dimensional representation of Earth’s properties as a function of its radius and explained many seismic observations in a broad frequency band. However, some discrepancies still exist among these models near the first-order discontinuities (e.g., the core-mantle and the inner-core boundaries) due to different datasets and [...]


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