Preprints
Filtering by Subject: Geomorphology
A dimensionless statistical analysis of logjam form and process
Published: 2017-11-01
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Engineering, Environmental Sciences, Geomorphology, Hydrology, Natural Resources Management and Policy, Physical Sciences and Mathematics, Sedimentology, Water Resource Management
Large wood in rivers and logjams are linked to the presence of varied riverine morphologies and increased abundance and diversity of aquatic biota. Current research into the ecohydrological, morphological and geochemical effects of logjams is restricted by difficulties in comparing findings between river systems. The problem is exacerbated by a lack of standardised metrics for recording and [...]
The Planform Mobility of River Channel Confluences: Insights from Analysis of Remotely Sensed Imagery
Published: 2017-11-01
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics, Sedimentology
River channel confluences are widely acknowledged as important geomorphological nodes that control the downstream routing of water and sediment, and which are locations for the preservation of thick fluvial deposits overlying a basal scour. Despite their importance, there has been little study of the stratigraphic characteristics of river junctions, or the role of confluence morphodynamics in [...]
Influence of cell size on volume calculation using digital terrain models: A case of coastal dune fields
Published: 2017-11-01
Subjects: Earth Sciences, Geographic Information Sciences, Geography, Geomorphology, Other Earth Sciences, Physical Sciences and Mathematics, Remote Sensing, Sedimentology, Social and Behavioral Sciences, Spatial Science
In this work, we analyze how variation in cell size influences the volume calculated from Digital Terrain Models (DTMs) derived from a LiDAR (Light Detection and Ranging) survey in two coastal Late Holocene dune fields in southern Brazil. Cell size varied from 1 to 100 m. The RMSE (Root Mean Square Error) of the resampled DTMs from the original LiDAR (with 0.5 m resolution) increases linearly [...]
Multi-scale Analysis of Topographic Surface Roughness in the Midland Valley, Scotland
Published: 2017-11-01
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 [...]
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 [...]
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 [...]
Spatially explicit spectral analysis of point clouds and geospatial data
Published: 2017-10-31
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 [...]
Shallow water benthic imaging and substrate characterization using recreational-grade sidescan-sonar
Published: 2017-10-31
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geomorphology, Hydraulic Engineering, Physical Sciences and Mathematics, Sedimentology
In recent years, lightweight, inexpensive, vessel-mounted ‘recreational grade’ sonar systems have rapidly grown in popularity among aquatic scientists, for swath imaging of benthic substrates. To promote an ongoing ‘democratization’ of acoustical imaging of shallow water environments, methods to carry out geometric and radiometric correction and georectification of sonar echograms are presented, [...]
Development of cutoff-related knickpoints during early evolution of submarine channels
Published: 2017-10-31
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics
Submarine channels are often thought of as having relatively simple geometries, with significant along-channel morphologic and stratigraphic continuity. Using high-resolution seismic reflection data from offshore Angola and a kinematic model of channel evolution, we present evidence that channels on the seafloor can develop slope variability as a result of meander cutoff events. When cutoffs [...]
SRTM-based morphotectonic analysis of the Poços de Caldas Alkaline Massif, southeastern Brazil
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
An evaluation of SRTM 03” data applicability in geomorphology and morphotectonics analysis is proposed, considering the morphometric parameters slope, aspect, surface roughness and isobase surface. The study area, in southeastern Brazil, comprises the Poços de Caldas Alkaline Massif, a 33km-diameter Late Cretaceous collapsed volcanic caldera. Morphometric indices evaluated showed the correlation [...]
Resampling SRTM 03”-data with kriging
Published: 2017-10-31
Subjects: Computer Sciences, Earth Sciences, Geographic Information Sciences, Geography, Geomorphology, Physical Sciences and Mathematics, Social and Behavioral Sciences, Spatial Science
The purpose of this article is to present the steps necessary to improve the resolution of a DEM us- ing variogram modelling and kriging, as well as a brief comparison of the results with those obtained with interpolation by Regularised Splines with Ten- sion (RST).