Preprints
Filtering by Subject: Physical Sciences and Mathematics
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 [...]
Fast anisotropic Mg and H diffusion in wet forsterite
Published: 2021-10-29
Subjects: Physical Sciences and Mathematics
Mg diffusion, which is important for properties of forsterite such as conductivity and deformation, is a strong function of water content. The mechanism behind this effect, however, has not been fully elucidated. In this study we use Density Functional Theory to predict the diffusivity of 〖(2H)〗_Mg^X and we find that they are around 1000 times slower than H-free Mg vacancies V_Mg^''. In most [...]
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 [...]
A 18,000 yr record of tropical land temperature, convective activity and rainfall seasonality from the maritime continent
Published: 2021-10-27
Subjects: Biogeochemistry, Climate, Earth Sciences, Geology, Physical Sciences and Mathematics, Planetary Hydrology
The maritime continent exports an enormous amount of heat and moisture to the rest of the globe via deep atmospheric convection. How this export has changed through time during the last deglacial period and through the Holocene, is hardly known yet critical for the understanding of global climate dynamics. Here we present a continuous paleoclimate record from southern Thailand covering the last [...]
Carbon dioxide emissions rebound from the COVID-19 pandemic
Published: 2021-10-27
Subjects: Physical Sciences and Mathematics
Global CO2 emissions have rebounded strongly from the historic decrease caused by the COVID 19 pandemic in 2020. We project 2021 emissions will be only 0.9% less than the record levels of 2019. In particular, power- and industry-related emissions in China and India have increased relative to 2019, and the carbon intensity of electricity used worldwide has returned to its pre-pandemic level. Is [...]
Feasibility of Afforestation as an Equitable Nature-Based Solution in Urban Areas
Published: 2021-10-23
Subjects: Physical Sciences and Mathematics
Although nature-based solutions for urban heat mitigation have gained momentum, it is important to quantitatively assess the feasibility of such strategies to utilize space efficiently and prioritize lower-income communities, who have fewer options for climate change adaptation. Here we combine data from US census estimates, satellites, and satellite-derived products to develop a framework to [...]
Late Eocene-early Oligocene paleoenvironmental changes recorded at Lühe, Yunnan, southwestern China
Published: 2021-10-23
Subjects: Physical Sciences and Mathematics
During the late Eocene to the early Oligocene, marine records document a globally congruent record of declining carbon dioxide concentrations, Antarctic icesheet growth, and associated reorganisation of the global climate system. In contrast, the few existing terrestrial records demonstrate high heterogeneity of environmental change and are difficult to reconcile with those of the oceanic realm. [...]
Sharp-based, mixed carbonate-siliciclastic shallow-marine deposits (upper Miocene, Betic Cordillera, Spain): the record of ancient transgressive shelf ridges?
Published: 2021-10-23
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Isolated sharp-based sedimentary bodies in shelf settings can develop via the reworking of regressive deposits during transgressions. An example of these are shelf ridges, formed under a wide range of processes, and widely studied due to their high reservoir potential. However, there is still a lack of examples in mixed (carbonate-siliciclastic) successions. This study presents an outcrop example [...]
Constraints on the ice composition of carbonaceous chondrites from their magnetic mineralogy
Published: 2021-10-22
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Planetary Sciences
Carbonaceous chondrites experienced varying degrees of aqueous alteration on their parent asteroids, which influenced their mineralogies, textures, and bulk chemical and isotopic compositions. Although this alteration was a crucial event in the history of these meteorites, their various alteration pathways are not well understood. One phase that formed during this alteration was magnetite, and [...]
Fe5S2 identified as a host for sulfur in Earth and planetary cores
Published: 2021-10-22
Subjects: Physical Sciences and Mathematics
Cosmochemical considerations suggest that sulfur is a candidate light alloying element in rocky planetary cores, such that the high pressure-temperature (P-T) Fe-S phase relations likely play a key role in planetary core crystallization thermodynamics. The iron-saturated Fe-S phase relations were investigated to 200 GPa and 3250 K using combined powder and single-crystal X-ray diffraction [...]
The seismic wavefield as seen by Distributed Acoustic Sensing (DAS) arrays: local, regional and teleseismic sources
Published: 2021-10-20
Subjects: Earth Sciences, Physical Sciences and Mathematics
Distributed acoustic sensing (DAS) exploiting fibre optic cables provides a means for high-density sampling of the seismic wavefield. The scattered returns from multiple laser pulses provide local averages of strain rate over a finite gauge length, and the nature of the signal depends on the orientation of the cable with respect to the passing seismic waves. The properties of the wavefield in [...]
Linking technical geothermal potential from borehole heat exchangers and heating demand scenarios on a regional scale
Published: 2021-10-20
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Natural Resources Management and Policy, Other Earth Sciences, Physical Sciences and Mathematics
Extracting shallow geothermal energy using borehole heat exchangers (BHEs) can help decarbonising the residential heating sector. To assist urban planers and policy makers in developing carbon-neutral heating plans the regional technical shallow geothermal potential must be analysed. Here, we propose a methodology to estimate the technical geothermal potential of BHE fields on a regional scale [...]
Ocean model response to stochastically perturbed momentum fluxes
Published: 2021-10-20
Subjects: Physical Sciences and Mathematics
In climate model configurations, standard approaches to the representation of unresolved, or subgrid scales, via deterministic closure schemes are being challenged by stochastic approaches inspired by statistical dynamical theory. Despite gaining popularity, studies of various stochastic subgrid scale parameterizations applied to atmospheric climate and weather prediction systems have revealed a [...]
Improving the reliability of Fe- and S-XANES measurements in silicate glasses: Correcting beam damage and identifying Fe-oxide nanolites in hydrous and anhydrous melt inclusions
Published: 2021-10-19
Subjects: Geochemistry, Geology, Mineral Physics, Physical Sciences and Mathematics, Volcanology
The redox state of silicate melts influences crystallization, element partitioning, and degassing behavior. Synchrotron-based micro-X-ray absorption near edge structure (μXANES) spectroscopy has emerged as a powerful tool for determining redox conditions through the direct measurement of speciation of multivalent elements such as iron and sulfur in silicate glasses. In particular, the high [...]
Evolution of seafloor pockmarks along the Northern Orange Basin, Offshore South Africa: Interplay between fluid flow and bottom current activities
Published: 2021-10-19
Subjects: Physical Sciences and Mathematics
Pockmarks are pervasive geomorphologic features identified along continental margins resulting from fluid expulsion on the seafloor. However, the understanding of the underlying geological mechanism/control in relation to their evolution, distribution, and morphology is limited, especially along data-starved continental margins such as the Northern Orange Basin. Analysis of a high-quality 3D [...]