Preprints
There are 6976 Preprints listed.
An optimization method for paleomagnetic Euler pole analysis
Published: 2021-11-15
Subjects: Geology, Geophysics and Seismology
Owing to the axial symmetry of the Earth’s magnetic field, paleomagnetic data only directly record the latitudinal and azimuthal positions of crustal blocks in the past, and paleolongitude cannot be constrained. An ability to overcome this obstacle is thus of fundamental importance to paleogeographic reconstruction. Paleomagnetic Euler pole (PEP) analysis presents a unique means to recover such [...]
Emergence of anthropogenic fire regimes in the southern boreal of Canada
Published: 2021-10-29
Subjects: Biogeochemistry, Earth Sciences, Ecology and Evolutionary Biology, Environmental Sciences, Forest Sciences, Life Sciences, Plant Sciences
While radiative forcing and thus land surface temperatures have been shown to positively correlate with fire severity, precipitation, and lightning strike frequency, the effects of human activity on fire regimes remain difficult to disentangle from geophysical drivers given co-variation between these factors. Here, I analyze fire regimes in the 1919-2012 period across Canada and compare national [...]
Simulated decline of a northern forest due to anthropogenic controls on the regeneration-mortality balance
Published: 2021-10-29
Subjects: Biodiversity, Biogeochemistry, Earth Sciences, Ecology and Evolutionary Biology, Environmental Sciences, Forest Sciences, Life Sciences, Physical Sciences and Mathematics, Plant Sciences
The population structure of forests is shaped by balancing the opposing forces of regeneration and mortality, each of which influence C turnover rates and are sensitive to climate. Regeneration underlies the migrational potential of forests to climatic change and remains underserved in modeling studies. Our objective was to test the hypothesis that warming may reduce tree regeneration rates while [...]
Bridging knowledge gaps with hybrid machine-learning forest ecosystem models (ML-FEMs): inferential simulation of past understory light regimes
Published: 2021-10-29
Subjects: Artificial Intelligence and Robotics, Biodiversity, Biogeochemistry, Computer Sciences, Earth Sciences, Ecology and Evolutionary Biology, Forest Sciences, Life Sciences, Physical Sciences and Mathematics, Plant Sciences
Soil moisture is a key limiting factor of plant productivity in boreal and montane regions, producing additional climate feedbacks through evaporation, regeneration, mortality, and respiration. Understory solar irradiation – the primary driver of surface temperature and evaporative demand – remains poorly represented in vegetation models due to a lack of 3-D canopy geometry. Existing models are [...]
Airborne laser scanning proxies of canopy light transmission in forests
Published: 2021-10-29
Subjects: Biodiversity, Biogeochemistry, Computer Sciences, Earth Sciences, Ecology and Evolutionary Biology, Environmental Sciences, Forest Sciences, Life Sciences, Physical Sciences and Mathematics, Plant Sciences, Software Engineering, Statistics and Probability
Reliable estimates of canopy light transmission are critical to understanding the structure and function of vegetation communities but are difficult and costly to attain by traditional field inventory methods. Airborne laser scanning (ALS) data uniquely provide multi-angular vertically resolved representation of canopy geometry across large geographic areas. While previous studies have proposed [...]
Potency density tensor inversion of complex body waveforms with time-adaptive smoothing constraint
Published: 2021-10-28
Subjects: Physical Sciences and Mathematics
Large earthquakes are often accompanied by complex fault rupture, but it has been difficult to reliably estimate such a complex rupture process with conventional waveform analysis tools due to modelling errors originating from limited accuracy of the fault geometry. Recently, a potency density tensor inversion method has been developed to solve this problem; allowing any types of faulting [...]
Constraints on the behaviour and content of volatiles in Galápagos magmas from melt inclusions and nominally anhydrous minerals
Published: 2021-10-30
Subjects: Physical Sciences and Mathematics
Despite their relatively low concentration in most oceanic basalts, volatile species (e.g. H2O, CO2 and S) have a disproportionately large influence on a wide range of mantle and magmatic processes. However, constraining the concentration of H2O (and other volatiles) in basaltic magmas is not straightforward as submarine glass analyses are influenced by assimilation of hydrothermal brines, and [...]
Vertical Deformation and Residual Altimeter Systematic Errors around Continental Australia Inferred from a Kalman-Based Approach
Published: 2021-11-15
Subjects: Earth Sciences, Environmental Monitoring, Other Earth Sciences
We further developed a space-time Kalman approach to estimate time-variable signals in residual altimeter systematic errors and vertical land motion (VLM) around the Australian coast since the 1990s, through combining multi-mission absolute sea-level (ASL), relative sea-level (RSL) from tide gauges (TGs) and GPS heights records. Our results confirmed continent-wide subsidence and TG-specific VLMs [...]
On the impact of urbanisation on CO2 emissions
Published: 2021-11-01
Subjects: Physical Sciences and Mathematics
We use a globally consistent, time-resolved data set of CO2 emission proxies to quantify urban CO2 emissions in 91 cities. We decompose emission trends into contributions from changes in urban extent, population density and per capita emission. We find that urban CO2 emissions are increasing everywhere but that the dominant contributors differ according to development level. A cluster analysis of [...]
Hemispheric geochemical dichotomy of the mantle is a legacy of austral supercontinent assembly and deep subduction of continental crust
Published: 2021-11-01
Subjects: Physical Sciences and Mathematics
Oceanic hotspots with extreme enriched mantle radiogenic isotopic signatures—including high 87Sr/86Sr and low 143Nd/144Nd indicative of ancient subduction of continental crust—are restricted to the southern hemispheric mantle. However, the mechanisms responsible for concentrating subducted continental crust in the austral mantle are unknown. We show subduction of sediments and subduction eroded [...]
From offshore to onshore probabilistic tsunami hazard assessment via efficient Monte-Carlo sampling
Published: 2021-11-01
Subjects: Earth Sciences, Other Earth Sciences
Offshore Probabilistic Tsunami Hazard Assessments (offshore PTHAs) provide large-scale analyses of earthquake-tsunami frequencies and uncertainties in the deep ocean, but do not provide high-resolution onshore tsunami hazard information as required for many risk-management applications. To understand the implications of an offshore PTHA for the onshore hazard at any site, in principle the tsunami [...]
Introducing StreamProfilerApp, a web application for near-global, exploratory, longitudinal river profile analysis
Published: 2021-11-03
Subjects: Earth Sciences, Education
Stream profile analysis has been used extensively in the earth sciences. In the past, exploration of stream profiles has required downloading and processing Digital Elevation Models (DEMs) for specific areas, which limits the scope of exploratory analysis. Presented here is a web application designed to analyze stream profiles at 90m resolution at a near-global scale. Based on the Hydrosheds [...]
Toward the understanding of saline water intrusion and nutrient flushing in Lake Nokoué
Published: 2021-11-03
Subjects: Life Sciences
To understand the salinity dynamic at the outlet of Lake Nokoué and to simulate the nutrient flushing from this lake into the Atlantic Ocean, a 2D hydrodynamic model was designed with Mike 21. The choice of the Mike 21 was motivated by the long practice that decision-makers in Benin have with this software. The Hydrodynamics (HD) module simulated water level variations and flows in response, [...]
Subsurface temperature from seismic reflections: application to the post break up sequence offshore Namibia
Published: 2021-11-05
Subjects: Earth Sciences, Geology, Geophysics and Seismology
Accurate estimations of present-day subsurface temperatures are of critical importance to the energy industry, in particular with regards to geothermal energy and petroleum exploration. In frontier basins, the subsurface temperature regime can give an indication of the hydrocarbon potential of source horizons. The Lüderitz Basin, offshore Namibia, is a frontier deep water basin located on a [...]
Regional analysis of climate projections using Bias Corrected spatial disaggregated super-resolution convolutional neural networks
Published: 2021-11-04
Subjects: Engineering, Life Sciences, Physical Sciences and Mathematics
Climate change is very crucial for ecological systems and society. But Global climate models run at coarse spatial resolution which is difficult to do regional analysis. Regional-scale projections can be obtained by a technique called statistical downscaling which uses past data to find out the high resolution and low-resolution mapping. There are many methods for statistical downscaling of [...]