Preprints
Filtering by Subject: Physical Sciences and Mathematics
The carbon cycle of southeast Australia during 2019-2020: Drought, fires and subsequent recovery
Published: 2021-05-13
Subjects: Atmospheric Sciences, Environmental Monitoring, Environmental Sciences, Forest Sciences, Physical Sciences and Mathematics
2019 was the hottest and driest year on record for southeast Australia leading to bushfires of unprecedented extent. Ecosystem carbon losses due to drought and fire are believed to have been substantial, but have not been well quantified. Here, we utilize space-based measurements of trace gases (TROPOspheric Monitoring Instrument XCO, Orbiting Carbon Observatory 2 XCO2) and up-scaled GPP (FluxSat [...]
A damage model for the frictional shear failure of brittle materials in compression
Published: 2021-05-13
Subjects: Applied Mathematics, Computational Engineering, Earth Sciences, Engineering, Geology, Materials Science and Engineering, Physical Sciences and Mathematics
Damage models have been successfully employed for many decades in the modelling of tensile failure, where the crack surfaces separate as a crack grows. The advantage of this approach is that crack trajectories can be computed simply and efficiently on a fixed finite element mesh without explicit tracking. The development of damage models for shear failure in compression, where the crack faces [...]
Influence of variable decoupling between vertically separated fault populations on structural inheritance – The Laminaria High, NW Shelf of Australia
Published: 2021-05-13
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
When extension events are greatly separated in time, older faults may be buried and stratigraphically separated from newly developing faults at shallower depths. During rifting, the buried structures may reactivate and propagate upwards to be expressed within the shallow system. The degree of linkage between structural levels determines the influence that the deeper structures can exert over the [...]
Distributed chaos of the atmospheric tracers
Published: 2021-05-13
Subjects: Physical Sciences and Mathematics
It is shown, using results of numerical simulations, atmospheric experiments and observations with natural trace-gases (ozone, carbon dioxide etc.), that the spatio-temporal distributed chaos can provide good quantitative description of the statistical properties of the passive scalar tracers in the atmosphere from the atmospheric surface layer up to the stratosphere. Related properties of the [...]
A Persistent Non-uniformitarian Paleomagnetic Field in the Devonian?
Published: 2021-05-13
Subjects: Physical Sciences and Mathematics
The Devonian, like much of the Paleozoic, has long been a problematic period for paleomagnetism. Devonian paleomagnetic data are generally difficult to interpret and have complex partial or full overprints; problems that arise in data obtained from both sedimentary and igneous rocks. As a result, the reconstruction of tectonic plate motions, performed largely using apparent polar wander paths, [...]
Structural Inheritance Controls Strain Distribution During Early Continental Rifting, Rukwa Rift
Published: 2021-05-13
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Little is known about rift kinematics and strain distribution during the earliest phase of extension due to the deep burial of the pre-rift and earliest rift structures beneath younger, rift-related deposits. Yet, this exact phase of basin development ultimately sets the stage for the location of continental plate divergence and breakup. Here, we investigate the structure and strain distribution [...]
Thermo-Chemical Dynamics in Earth's Core Arising from Interactions with the Mantle
Published: 2021-05-08
Subjects: Physical Sciences and Mathematics
Thermo-chemical interactions at the core-mantle boundary (CMB) play an integral role in determining the dynamics and evolution Earth's deep interior. This review considers the processes in the core that arise from heat and mass transfer at the CMB, with particular focus on thermo-chemical stratification and the precipitation of oxides. A fundamental parameter is the thermal conductivity of the [...]
The influence of crustal strength on rift geometry and development – Insights from 3D numerical modelling
Published: 2021-05-07
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The lateral distribution of strength within the crust is non-uniform, dictated by crustal lithology and the presence and distribution of heterogeneities within it. During continental extension, areas of crust with distinct lithological and rheological properties manifest strain differently, influencing the structural style, geometry and evolution of the developing rift system. Here, we use 3D [...]
On the Land Emissivity Assumption and Landsat-Derived Surface Urban Heat Islands: A Global Analysis
Published: 2021-05-07
Subjects: Physical Sciences and Mathematics
The prescription of surface emissivity (ε) strongly controls satellite-derived estimates of land surface temperature (LST). This is particularly important for studying surface urban heat islands (SUHI) since built-up and natural landscapes are known to have distinct ε values. Given the small signal associated with the SUHI compared to LST, accurately prescribing urban and rural ε would improve [...]
Hydroclimatic Analysis of Rising Water Levels in the Great Rift Valley Lakes of Kenya
Published: 2021-05-06
Subjects: Engineering, Physical Sciences and Mathematics
Study Region The Great Rift Valley lakes of Kenya have recently experienced significant increases in their water levels, negatively impacting the local communities. This has provoked renewed concerns about the causations, with various geological, anthropogenic and hydro-climatic influences hypothesized as potential causes of the water level rises. Study Focus This study analyses and documents [...]
Tectonic geomorphology of the Jhelum fault zone & its contiguous regions in western Himalaya
Published: 2021-05-02
Subjects: Education, Physical Sciences and Mathematics
The western Himalayan syntaxis represents the region where the major Himalayan structures abruptly curve and the cause of the curvature and the tectonic geomorphology of the region has not been fully explored. The lack of detailed structural maps with extensive field-based data is missing, which is mainly because of the political problems related to border sharing between Pakistan, India, and [...]
CO2 capture by pumping surface acidity to the deep ocean
Published: 2021-04-30
Subjects: Chemical Engineering, Climate, Engineering, Environmental Engineering, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The majority of IPCC scenarios call for active CO2 removal (CDR) to remain below 2oC of warm- ing. On geological timescales, ocean uptake regulates atmospheric CO2 concentration, with two homeostats driving CO2 uptake: dissolution of deep ocean calcite deposits and terrestrial weathering of silicate rocks, acting on 1ka to 100ka timescales, respectively. Many current ocean-based CDR proposals [...]
Use of environmental tracers (tritium3H and SF6) to improve knowledge of aquifer storage capacity, residence time and sustainability in the crystalline rock island aquifer of Tobago, West Indies.
Published: 2021-04-29
Subjects: Physical Sciences and Mathematics
Understanding the residence time, flow velocities and storage volumes in fractured rock aquifers is essential for assessing the sustainable use of groundwater in island aquifer systems. Environmental tracers such as tritium (3H) and sulfur hexafluoride (SF6) that enter the aquifer systems through natural hydrological processes are effectively used to quantify the “apparent age” of young [...]
Expert judgements on solar geoengineering research priorities and challenges
Published: 2021-04-29
Subjects: Physical Sciences and Mathematics, Social and Behavioral Sciences
Solar geoengineering describes a set of proposals to deliberately alter the earth’s radiative balance to reduce climate risks. We elicit judgements on natural science research priorities for solar geoengineering through a survey and in-person discussion with 72 subject matter experts, including two thirds of all scientists with ≥10 publications on the topic. Experts prioritized Earth system [...]
Probing the nucleation of iron in Earth’s core using MD simulations of supercooled liquids
Published: 2021-04-29
Subjects: Earth Sciences, Physical Sciences and Mathematics
Classical nucleation theory describes the formation of the first solids from supercooled liquids and predicts an average waiting time for a system to freeze as it is supercooled to temperatures below the melting temperature. For systems at low to moderate undercooling, waiting times are too long for freezing to be observed via experiment or simulation. Here a system can be described by estimated [...]