Preprints
Filtering by Subject: Earth Sciences
A linear dynamical systems approach to streamflow reconstruction reveals history of regime shifts in northern Thailand
Published: 2017-11-01
Subjects: Applied Mathematics, Dynamic Systems, Earth Sciences, Hydrology, Physical Sciences and Mathematics
Catchment dynamics is not often modeled in streamflow reconstruction studies; yet, the streamflow generation process depends on both catchment state and climatic inputs. To explicitly account for this interaction, we contribute a linear dynamic model, in which streamflow is a function of both catchment state (i.e., wet/dry) and paleo-climatic proxies. The model is learned using a novel variant of [...]
Determining geophysical responses from burials in graveyards and cemeteries
Published: 2017-10-31
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Graveyards and cemeteries around the world are increasingly designated as full. There is therefore a requirement to identify vacant spaces for new burials or to identify existing ones to exhume and then re-inter if necessary. Geophysical methods offer a potentially non-invasive target detection solution; however, there has been limited research to identify optimal geophysical detection methods [...]
Multi-scale Analysis of Topographic Surface Roughness in the Midland Valley, Scotland
Published: 2017-10-31
Subjects: Earth Sciences, Geographic Information Sciences, Geography, Geomorphology, Other Earth Sciences, Physical Sciences and Mathematics, Remote Sensing, Social and Behavioral Sciences, Spatial Science, Tectonics and Structure
Surface roughness is an important geomorphological variable which has been used in the earth and planetary sciences to infer material properties, current/past processes and the time elapsed since formation. No single definition exists, however within the context of geomorphometry we use surface roughness as a expression of the variability of a topographic surface at a given scale, where the scale [...]
Constraining the sedimentology and stratigraphy of submarine intraslope lobe deposits using exhumed examples from the Karoo Basin, South Africa
Published: 2017-10-31
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology
Intraslope lobe deposits provide a record of the infill of accommodation on submarine slopes and their recognition enables the accurate reconstruction of the stratigraphic evolution of submarine slope systems. Extensive exposures of discrete sand-prone packages in Units D/E and E, Fort Brown Formation, Karoo Basin, South Africa, permit analysis of the sedimentology and stacking patterns of three [...]
Electromagnetic torques in the core and resonant excitation of decadal polar motion
Published: 2017-10-31
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Motion of the rotation axis of the Earth contains decadal variations with amplitudes on the order of 10 mas. The origin of these decadal polar motions is unknown. A class of rotational normal modes of the core–mantle system termed torsional oscillations are known to affect the length of day (LOD) at decadal periods and have also been suggested as a possible excitation source for the observed [...]
A general model for the helical structure of geophysical flows in channel bends
Published: 2017-10-31
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Engineering, Environmental Sciences, Fluid Dynamics, Geology, Geomorphology, Geophysics and Seismology, Hydrology, Life Sciences, Natural Resources and Conservation, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Oil, Gas, and Energy, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics, Physics, Risk Analysis, Sedimentology
Meandering channels host geophysical flows that form the most extensive sediment transport systems on Earth (i.e. rivers and submarine channels). Measurements of helical flow structures in bends have been key to understanding sediment transport in rivers. Turbidity currents differ from rivers in both density and velocity profiles. These differences, and the lack of field measurements of turbidity [...]
Análise digital de terreno e evolução de longo-termo de relevo do centro-leste brasileiro
Published: 2017-10-31
Subjects: Earth Sciences, Geographic Information Sciences, Geography, Geomorphology, Physical Sciences and Mathematics, Social and Behavioral Sciences, Spatial Science, Tectonics and Structure
Geomorphological theories for long-term relief evolution postulate the existence of planation surfaces, created by the con- tinuous work of erosion/deposition during periods of tectonic quiescence and recognized as extensive areas of very gentle relief disturbed only locally by residual elevations, or by the apparent leveling of summit heights in a given region. After decades since the [...]
Quantificação da Deformação Finita nos Metagranitoides Cariris Velhos na Região de Alagoa Grande (PB)
Published: 2017-10-31
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
The Cariris Velhos Metagranitoids are considered an important geological unit of the Transversal Zone (Borborema Province – NE Brazil). We evaluated the use of raw and processed digital images to obtain the deformation ellipsoid for the Cariris Velhos Metagranitoids using the Inertia Tensor and Intercepts methods. The ellipsoid symmetry of the deformed fabric was very similar for both methods, [...]
Comparison of roving-window and search-window techniques for characterising landscape morphometry
Published: 2017-10-31
Subjects: Computer Sciences, Earth Sciences, Geographic Information Sciences, Geography, Geomorphology, Physical Sciences and Mathematics, Social and Behavioral Sciences, Spatial Science, Theory and Algorithms
Neighbourhood analysis in a Geographical Information System (GIS) calculates the value of a given raster cell from the values of its neighboring cells. Common operations include filtering (high-pass, low-pass, etc) and smoothing (mean, mode) of data, operations that can be done by means of roving-windows or search-windows. Digital terrain analysis (or geomorphometry) relies on neighbourhood [...]
SRTM resample with short distance-low nugget kriging
Published: 2017-10-31
Subjects: Earth Sciences, Geographic Information Sciences, Geography, Geomorphology, Other Earth Sciences, Physical Sciences and Mathematics, Social and Behavioral Sciences, Spatial Science, Tectonics and Structure
The Shuttle Radar Topography Mission (SRTM), was flow on Space Shuttle Endeavour in February 2000, with the objective of acquire a digital elevation model of all land between 60º north latitude and 56º south latitude, using Interferometric Synthetic Aperture Radar (InSAR) techniques. SRTM data is distributed at horizontal resolution of 1 arc-second (aprox. 30m) for areas within the USA and at 3 [...]
Aplicações dos modelos de elevação SRTM em geomorfologia
Published: 2017-10-31
Subjects: Earth Sciences, Geographic Information Sciences, Geography, Geomorphology, Other Earth Sciences, Physical Sciences and Mathematics, Remote Sensing, Social and Behavioral Sciences, Spatial Science
A missão Shuttle Radar Topography Mission (SRTM) foi realizada para mapear o relevo da área continental da Terra com interferometria de radar entre 60º de latitude norte e 54º de latitude sul. A utilização de Modelos Digitais de Elevação (MDEs) em geomorfologia permite o cálculo de variáveis associadas ao relevo com rapidez e precisão. Neste artigo, apresenta-se uma visão geral de aplicações dos [...]
Nature, origin and evolution of a Late Pleistocene incised valley-fill, Sunda Shelf, Southeast Asia
Published: 2017-10-31
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Understanding the stratigraphic fill and reconstructing the palaeo-hydrology of incised valleys can help to constrain those factors that controlled their origin, evolution and regional significance. This condition is addressed through the analysis of a large (up to 18 km wide by 80 m deep) and exceptionally well-imaged Late Pleistocene incised valley from the Sunda Shelf (South China Sea) based [...]
Fluctuation Analysis of Redox Potential to Distinguish Microbial Fe(II) Oxidation
Published: 2017-10-30
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Physical Sciences and Mathematics
We developed a novel method for distinguishing abiotic and biological iron oxidation in liquid media using oxidation-reduction (redox) potential time series data. The instrument and processing algorithm were tested by immersing the tip of a Pt electrode with an Ag-AgCl reference electrode, into an active iron-oxidizing biofilm in a groundwater discharge zone, as well as in two abiotic systems: a [...]
Bacterial Fe(II)-oxidation Distinguished by Long-Range Correlation in Redox Potential
Published: 2017-10-30
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Physical Sciences and Mathematics
The kinetics of bacterial Fe(II) oxidation was investigated 297m underground at the Äspö Hard Rock Laboratory (near Oskarshamn, Sweden) under steady state groundwater flow conditions in a flow-through cell containing well-developed flocculent mats of bacteriogenic iron oxides (BIOS). Pseudo first-order rate constants of 0.004 min^-1 and 0.009 min^-1 were obtained for chemical and bacterial [...]
Spatially explicit spectral analysis of point clouds and geospatial data
Published: 2017-10-30
Subjects: Civil and Environmental Engineering, Civil Engineering, Computer Sciences, Earth Sciences, Engineering, Geomorphology, Geophysics and Seismology, Numerical Analysis and Scientific Computing, Physical Sciences and Mathematics, Sedimentology
The increasing use of spatially explicit analyses of high-resolution spatially distributed data (imagery and point clouds) for the purposes of characterising spatial heterogeneity in geophysical phenomena necessitates the development of custom analytical and computational tools. In recent years, such analyses have become the basis of, for example, automated texture characterisation and [...]