Preprints
There are 4725 Preprints listed.
Phosphorus supply affects long-term carbon accumulation in mid-latitude ombrotrophic peatlands
Published: 2021-03-12
Subjects: Earth Sciences, Environmental Sciences
Ombrotrophic peatlands are a globally important carbon store and depend on atmospheric nutrient deposition to balance ecosystem productivity and microbial decomposition. Human activities have increased atmospheric nutrient fluxes, but the impacts of variability in phosphorus supply on carbon sequestration in ombrotrophic peatlands are unclear. Here, we synthesise phosphorus, nitrogen and carbon [...]
The Ca and Mg isotope record of the Cryogenian Trezona carbon isotope excursion
Published: 2021-03-11
Subjects: Earth Sciences, Geochemistry, Geology, Sedimentology, Stratigraphy
The Trezona carbon isotope excursion is recorded on five different continents in platform carbonates deposited prior to the end-Cryogenian Marinoan glaciation (>635 Ma) and represents a change in carbon isotope values of 16-18 per mill. Based on the spatial and temporal reproducibility, the excursion previously has been interpreted as tracking the carbon isotopic composition of dissolved [...]
The imprint of erosion by glacial lake outburst floods in the topography of central Himalayan rivers
Published: 2021-03-11
Subjects: Earth Sciences, Geomorphology
In steep landscapes, river incision sets the pace of landscape evolution. Transport of coarse sediment controls incision by evacuating material delivered to river channels by landslides. However, large landslide-derived boulders that impede bedrock erosion are immobile even in major runoff-driven floods. Glacial lake outburst floods (GLOFs) mobilize these boulders and drive incision, yet their [...]
Local and global controls on carbon isotope chemostratigraphy
Published: 2021-03-11
Subjects: Earth Sciences
Over million-year timescales, the geologic cycling of carbon controls long-term climate and the oxidation of Earth's surface. Inferences about the carbon cycle can be made from time series of carbon isotopic ratios measured from sedimentary rocks. The foundational assumption for carbon isotope chemostratigraphy is that carbon isotope values reflect dissolved inorganic carbon in a well-mixed ocean [...]
Rise and fall of vegetation primary production resilience to climate variability anticipated by a large ensemble of Earth System Models’ simulations
Published: 2021-03-09
Subjects: Life Sciences
Climate change is affecting many aspects of natural ecosystems and society. Anticipating the changes in vegetation resilience – the plants’ capacity to cope with disturbances and shocks such as those related to climate variability and extremes – is critical to understand and project ecosystems’ responses to global change and the impacts on the related ecosystem services, to support mitigation [...]
Magma pathways in sill-complexes
Published: 2021-03-09
Subjects: Physical Sciences and Mathematics
The Loch Scridain Sill-complex on the Isle of Mull affords an opportunity to examine how magma moves through and builds sill-complexes (Holness & Humphreys 2003). For example, field and petrological evidence indicates the Tràigh Bhàn na Sgùrra Sill is segmented and comprised several thick channels, separated by thin sill portions, that facilitated longer-lived magma flow (Holness & Humphreys [...]
Segment tip geometry of sheet intrusions, I: Theory and numerical models for the role of tip shape in controlling propagation pathways.
Published: 2021-03-09
Subjects: Physical Sciences and Mathematics
Inferences about sheet intrusion emplacement mechanisms have been built largely on field observations of intrusion tip zones: magmatic systems that did not grow beyond their observed state. Here we use finite element simulation of elliptical to superelliptical crack tips, representing observed natural sill segments, to show the effect of sill tip shape in controlling local stress concentrations, [...]
Climate change risks to push one-third of global food production outside Safe Climatic Space
Published: 2021-03-09
Subjects: Agriculture, Earth Sciences, Environmental Sciences
Climate change will alter key climatic conditions which human societies directly rely on and which, for example, food production is adjusted to. Here, using Holdridge Life Zones, we define Safe Climatic Space (SCS), a concept that incorporates the decisive climatic characteristics of precipitation, temperature and aridity. This allows us first to define the climatic niche of current food [...]
Decadal shoreline erosion and recovery of beaches in modified and natural estuaries
Published: 2021-03-08
Subjects: Geomorphology, Physical Sciences and Mathematics
Sandy beaches in estuaries and bays (BEBs) are common landforms on the coasts of many major cities. They exist under a wide range of settings and their morphology is controlled by their distance from the estuary/bay entrance, exposure to different types of waves (e.g., ocean swells vs locally generated wind waves), proximity to flood-tide delta/shoals, and anthropogenic interventions (e.g., [...]
Recrystallization of ice enhances the creep and vulnerability to fracture of ice shelves
Published: 2021-03-08
Subjects: Earth Sciences, Geophysics and Seismology, Glaciology, Physical Sciences and Mathematics
The initiation of fractures and fast flow in floating regions of Antarctica have the potential to destabilize large regions of the grounded ice sheet, leading to significant sea-level rise. While observations have shown rapid, localized deformation and damage in the margins of fast-flowing glaciers, there remain gaps in our understanding of how rapid deformation affects the viscosity and [...]
A Regional Semi-Distributed Streamflow Model Using Deep Learning
Published: 2021-03-08
Subjects: Civil and Environmental Engineering, Engineering, Environmental Studies, Hydrology
Recent studies have shown that deep learning models in hydrological applications significantly improved streamflow predictions at multiple stations compared to traditional machine learning approaches. However, most studies lack generalization; i.e. researchers are training separate models for each location. The spatial and temporal generalization ability of deep learning models in hydrology that [...]
fv3gfs-wrapper: a Python wrapper of the FV3GFS atmospheric model
Published: 2021-03-06
Subjects: Atmospheric Sciences, Software Engineering
Simulation software in geophysics is traditionally written in Fortran or C++ due to the stringent performance requirements these codes have to satisfy. As a result, these codes are often hard to understand, hard to modify and hard to interface with high-productivity languages used for exploratory work. \texttt{fv3gfs-wrapper} is an open-source Python-wrapped version of NOAA's FV3GFS global [...]
Topographic response to Neogene variations in slab geometry, climate and drainage reorganization in the Northern Andes of Colombia
Published: 2021-03-06
Subjects: Physical Sciences and Mathematics
The tropical Northern Andes of Colombia are one the world's most biodiverse places, offering an ideal location for unraveling the linkages between the geodynamic forces that build topography and the evolution of the biota that inhabit it. In this study, we utilize geomorphic analysis to characterize the topography of the Western and Central Cordilleras of the Northern Andes. We supplement our [...]
Mechanical properties of quartz sand and gypsum powder (plaster) mixtures: implications for laboratory model analogues for the Earth’s upper crust
Published: 2021-03-06
Subjects: Physical Sciences and Mathematics
Granular materials are a useful analogue for the Earth’s crust in laboratory models of deformation. Constraining their mechanical properties is critical for such model’s scaling and interpretation. Much information exists about monomineralic granular materials, such as quartz sand, but the mechanical characteristics of bimineralic mixtures, such as commonly-used quartz sand mixed with gypsum [...]
Land-tenure regimes determine tropical deforestation rates across socio-environmental contexts
Published: 2021-03-06
Subjects: Environmental Studies
Many tropical forestlands are experiencing changes in land-tenure regimes, but how these changes may affect deforestation rates remains ambiguous. Using Brazil’s uniquely comprehensive land-tenure and deforestation data and quasi-experimental methods, we analyzed causal effects of six alternative tenure regimes on deforestation across 49 spatiotemporal scales corresponding to distinct [...]