Preprints
Filtering by Subject: Physical Sciences and Mathematics
The stratigraphic record of continental breakup, offshore NW Australia
Published: 2021-06-24
Subjects: Physical Sciences and Mathematics
Continental breakup involves a transition from rapid, fault-controlled syn-rift subsidence to relatively slow, post-breakup subsidence induced lithospheric cooling. Yet the stratigraphic record of many rifted margins contain syn-breakup unconformities, indicating episodes of uplift and erosion interrupt this transition. This uplift has been linked to mantle upwelling, depth-dependent extension, [...]
Colonial history and global economics distort our understanding of deep-time biodiversity
Published: 2021-06-24
Subjects: Earth Sciences, Ecology and Evolutionary Biology, Life Sciences, Paleobiology, Paleontology, Physical Sciences and Mathematics
Sampling variations in the fossil record distort estimates of past biodiversity. However, compilations of global fossil occurrences used in these analyses not only reflect the geological and spatial aspects of the fossil record, but also the historical collation of these data. Here, we demonstrate how the legacy of colonialism as well as socio-economic factors such as wealth, education and [...]
Mass loss of the Antarctic ice sheet until the year 3000 under a sustained late-21st-century climate
Published: 2021-06-23
Subjects: Physical Sciences and Mathematics
Ice-sheet simulations of Antarctica extending to the year 3000 are analysed to investigate the long-term impacts of 21st century warming. Climate projections are used as forcing until 2100 and afterwards no climate trend is applied. Fourteen experiments are for the “unabated warming” pathway, and three are for the “reduced emissions” pathway. For the unabated warming path simulations, West [...]
Rotational Ground Motion Measurements for Regional Seismic Moment Tensors: a Review
Published: 2021-06-18
Subjects: Physical Sciences and Mathematics
Seismic moment tensors are an important tool in geosciences on all spatial scales and for a broad range of applications. The basic underlying theory is established since decades. However, various factors influence the reliability of the inversion result, several of them are mutually dependent. Hence, a reliable retrieval of seismic moment tensors is still hampered in many cases, especially at [...]
Geodynamic, geodetic, and seismic constraints favour deflated and dense-cored LLVPs
Published: 2021-06-18
Subjects: Cosmochemistry, Earth Sciences, Geochemistry, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics
Two continent-sized features in the deep mantle, the large low-velocity provinces (LLVPs), influence Earth's supercontinent cycles, mantle plume generation, and its geochemical budget. Seismological advances have steadily improved LLVP imaging, but several fundamental questions remain unanswered, including: What is their vertical extent? And, are they purely thermal anomalies, or are they also [...]
Past terrestrial hydroclimate driven by Earth System Feedbacks
Published: 2021-06-17
Subjects: Physical Sciences and Mathematics
Geologic evidence suggests drastic reorganizations of subtropical terrestrial hydroclimate during past warm intervals, including the mid-Piacenzian Warm Period (MP, 3.3 to 3.0 Ma). Despite having a similar to present-day atmospheric CO2 level (pCO2), MP featured moist subtropical conditions with high lake levels in Northern Africa, and mesic vegetation and sedimentary facies in subtropical [...]
Generation of Earth’s Early Continents From a Relatively Cool Archean Mantle
Published: 2021-06-17
Subjects: Physical Sciences and Mathematics
Several lines of evidence suggest that the Archean (4.0–2.5 Ga) mantle was hotter than today’s potential temperature (TP ) of 1350 ýC. However, the magnitude of such di erence is poorly constrained, with TP estimation spanning from 1500 ýC to 1600 ýC during the Meso-Archean (3.2-2.8 Ga). Such di erences have major implications for the interpreted mechanisms of continental crust generation on [...]
An Outsized Role for the Labrador Sea in the Multidecadal Variability of the Atlantic Overturning Circulation
Published: 2021-06-15
Subjects: Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Climate models are essential tools for investigating intrinsic North Atlantic variability related to variations in the Atlantic meridional overturning circulation (AMOC), but recent observations have called into question the fidelity of models that emphasize the importance of Labrador Sea processes. A multi-century pre-industrial climate simulation that resolves ocean mesoscale eddies has a [...]
Remote bed-level change and overwash observation with low-cost ultrasonic distance sensors
Published: 2021-06-12
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
Few datasets exist of high-frequency, in situ measurements of storm overwash, an essential mechanism for the subaerial maintenance of barrier islands and spits. Here we describe a new sensor platform for measuring bed-level change and estimating overwash inundation depths. Our MeOw (Measuring Overwash) stations consist of two ultrasonic distance sensors, a microprocessor board, and a camera and [...]
Ubiquity of human-induced changes in climate variability
Published: 2021-06-12
Subjects: Atmospheric Sciences, Biogeochemistry, Climate, Earth Sciences, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
While climate change mitigation targets necessarily concern maximum mean state changes, understanding impacts and developing adaptation strategies will be largely contingent on how climate variability responds to increasing anthropogenic perturbations. Here we present a new 100-member large ensemble of climate change projections conducted with the Community Earth System Model version 2 to examine [...]
The relative importance of wind-driven and chimney effect cave ventilation: Observations in Postojna Cave (Slovenia)
Published: 2021-06-11
Subjects: Physical Sciences and Mathematics
Density-driven chimney effect airflow is the most common form of cave ventilation, allowing gas exchange between the outside and the karst subsurface. However, cave ventilation can also be driven by other mechanisms, namely winds. We discuss the mechanism and dynamics of wind-driven ventilation using observations in Postojna Cave, Slovenia. We show how seasonal airflow patterns driven by the [...]
Flexural strike-slip basins
Published: 2021-06-10
Subjects: Physical Sciences and Mathematics
Strike-slip faults are classically associated with pull-apart basins where continental crust is thinned between two laterally offset fault segments. Here we propose a subsidence mechanism to explain the formation of a new type of basin where no substantial segment offset or syn-strike-slip thinning is observed. Such “flexural strike-slip basins” form due to a sediment load creating accommodation [...]
The hazards of unconfined pyroclastic density currents: a new synthesis and classification according to their deposits, dynamics, and thermal and impact characteristics
Published: 2021-06-08
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
Pyroclastic density currents (PDCs) that escape their confining channels are among the most dangerous of volcanic hazards. These unconfined PDCs are capable of inundating inhabited areas that may be unprepared for these hazards, resulting in significant loss of life and damage to infrastructure. Despite their ability to cause serious impacts, unconfined PDCs have previously only been described [...]
Use of multi-spectral visible and near-infrared satellite data for timely estimates of the Earth's surface reflectance in cloudy conditions: Part 2 - image restoration with HICO satellite data in overcast conditions
Published: 2021-06-08
Subjects: Physical Sciences and Mathematics
Satellite-based visible and near-infrared imaging of the Earth's surface is generally not performed in moderate to highly cloudy conditions; images that look visibly cloud covered to the human eye are typically discarded. Here, we expand upon previous work that employed machine learning (ML) to estimate underlying land surface reflectances at red, green, and blue (RGB) wavelengths in cloud [...]
On the statistical learning analysis of rain gauge data over the Natuna Islands
Published: 2021-06-08
Subjects: Applied Statistics, Atmospheric Sciences, Longitudinal Data Analysis and Time Series, Meteorology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Statistics and Probability
This article presents state-of-the-art statistical learning methods for analyzing rain gauge data over the Natuna Islands. By using shape preserving piecewise cubic interpolation, we managed to interpolate 671 null values from the daily precipitation data. Dominant periodicity analysis of daily precipitation signals using Lomb-Scargle Power Spectral Density shows annual, intraseasonal, and [...]