Preprints
Filtering by Subject: Physical Sciences and Mathematics
Prognostic validation of a neural network unified physics parameterization
Published: 2018-05-18
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Weather and climate models approximate diabatic and sub-grid-scale processes in terms of grid-scale variables using parameterizations. Current parameterizations are de- signed by humans based on physical understanding, observations and process modeling. As a result, they are numerically efficient and interpretable, but potentially over-simplified. However, the advent of global high-resolution [...]
Metabolite cycling indicated by long-range correlation in a sediment bioreactor mixed microbial community
Published: 2018-05-17
Subjects: Biogeochemistry, Earth Sciences, Environmental Sciences, Geochemistry, Physical Sciences and Mathematics
Geophysical surveys add value to biogeochemical studies because of their ability to characterize systems remotely, and their precise time resolution. One limitation, however, is their lack of biogeochemical process specificity. Here, electrochemical time series from an oxic-anoxic cyclical bioreactor experiment were reanalyzed with detrended fluctuation analysis (DFA) to distinguish dominant [...]
Surface albedo as a proxy for land-cover clearing in seasonally dry forests: evidence from the Brazilian Caatinga
Published: 2018-05-17
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Natural Resources and Conservation, Other Environmental Sciences, Physical Sciences and Mathematics
Ongoing increase in human and climate pressures, in addition to the lack of monitoring initiatives, makes the Caatinga one of the most vulnerable forests in the world. The Caatinga is located in the semi-arid region of Brazil and its vegetation phenology is highly dependent on precipitation, which has a high spatial and temporal variability. Under these circumstances, satellite image-based [...]
Dynamics of settling-driven convection beneath a sediment laden buoyant overflow: implications for the length-scale of deposition in lakes and the coastal ocean
Published: 2018-05-16
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology
The length-scale of deposition beneath a buoyant sediment-laden river plume can be strongly influenced by enhanced settling-driven convection, and is directly related to the horizontal velocity of the plume and a sedimentation time-scale. In our experiments, a buoyant plume of fresh water and sediment spreads over a denser saline layer. The speed of the plume increases with the net density [...]
Fish species classification in underwater video monitoring using Convolutional Neural Networks
Published: 2018-05-16
Subjects: Animal Sciences, Aquaculture and Fisheries Life Sciences, Computer Sciences, Environmental Monitoring, Environmental Sciences, Life Sciences, Other Life Sciences, Physical Sciences and Mathematics, Software Engineering
This report presents a case study for automatic fish species classification in underwater video monitoring of fish passes. Although the presented approach is based on the FishCam monitoring system, it can be used with any video-based monitoring system. The presented classification scheme in this study, is based on Convolutional Neural Networks that do not require the calculation of any [...]
Extrusion dynamics of deep-water volcanoes
Published: 2018-05-15
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Volcanology
Submarine volcanism accounts for c. 75% of the Earths volcanic activity. Yet difficulties with imaging their exteriors and interiors mean the extrusion dynamics and erupted volumes of deep water volcanoes remain poorly understood. Here, we use high-resolution 3-D seismic reflection data to examine the external and internal geometry, and extrusion dynamics of two Late Miocene-Quaternary, [...]
The land ice contribution to sea level during the satellite era
Published: 2018-05-14
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Since 1992, there has been a revolution in our ability to quantify the land ice contribution to SLR using a variety of satellite missions and technologies. Each mission has provided unique, but sometimes conflicting, insights into the mass trends of land ice. Over the last decade, over fifty estimates of land ice trends have been published, providing a confusing and often inconsistent picture. [...]
Increasingly Powerful Tornadoes in the United States
Published: 2018-05-11
Subjects: Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Storm reports show an upward trend in the power of tornadoes from longer and wider paths and higher damage ratings. Quantifying the magnitude of the increase is difficult given diurnal and seasonal influences on tornadoes embedded within natural variations and made worse by changes for rating damage. Here the authors solve this problem by fitting a statistical model to a metric of power during [...]
On the timing and nature of the multiple phases of slope instability on eastern Rockall Bank, Northeast Atlantic
Published: 2018-05-11
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology
One of the most challenging tasks when studying large submarine landslides is determining whether the landslide was initiated as a single large event, a chain of events closely spaced in time or multiple events separated by long periods of time as all have implications in risk assessments. In this study we combine new multichannel seismic profiles and new sediment cores with bathymetric data to [...]
Regional-scale paleobathymetry controlled location, but not magnitude, of tidal dynamics in the Late Cretaceous Western Interior Seaway, USA.
Published: 2018-05-11
Subjects: Earth Sciences, Life Sciences, Other Earth Sciences, Physical Sciences and Mathematics
Despite extensive outcrop and previous sedimentologic study, the role of tidal processes along sandy, wave- and river-dominated shorelines of the North American Cretaceous Western Interior Seaway remains uncertain, particularly for the extensive mid-Campanian (c. 75-77.5 Ma) tidal deposits of Utah and Colorado, USA. Herein paleotidal modelling, paleogeographic reconstructions, and interpretation [...]
Determination of the Lithosphere-Asthenosphere Boundary using program LABWA2015
Published: 2018-05-10
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Lithosphere-Asthenosphere Boundary (LAB) is a lower boundary of the lithospheric plate, so, it is an important tectonic boundary. We present the package of numerical program LABWA2015 developed for simple calculations of position of LAB. It assumes isostatic state and uses gravity as well as topographic data. However, program provides better results if additional geophysical data are used, e.g. [...]
The Mesozoic and Palaeozoic granitoids of north-western New Guinea
Published: 2018-05-09
Subjects: Earth Sciences, Geochemistry, Geology, Other Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
A large portion of the Birds Head Peninsula of NW New Guinea is an inlier that reveals the pre-Cenozoic geological history of the northern margin of eastern Gondwana. The peninsula is dominated by a regional basement high exposing Gondwanan (Australian) Palaeozoic metasediments intruded by Palaeozoic and Mesozoic granitoids. Here, we present the first comprehensive study of these granitoids, [...]
Growing forced bars determine non-ideal estuary planform
Published: 2018-05-09
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
The planform of estuaries is often described with an ideal shape, which exponentially converges in landward direction. We show how growing topographically forced nonmigratory (i.e., anchored) bars determine the large-scale estuary planform, which explains the deviations observed in the planform of natural estuaries filled with bars compared to the ideal planform. Experiments were conducted in a [...]
Combined geophysical measurements provide evidence for unfrozen water in permafrost in the Adventdalen valley in Svalbard
Published: 2018-05-07
Subjects: Earth Sciences, Geophysics and Seismology, Hydrology, Other Earth Sciences, Physical Sciences and Mathematics
Quantifying the unfrozen water content of permafrost is critical for assessing impacts of surface warming on the reactivation of groundwater flow and release of greenhouse gasses from degrading permafrost. Unfrozen water content was determined along a ~12 km transect in the Adventdalen valley in Svalbard, an area with continuous permafrost, using surface nuclear magnetic resonance and controlled [...]
Identifying causes of ground-penetrating radar reflections using time-domain reflectometry and sedimentological analyses
Published: 2018-05-07
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Sedimentology
Ground-penetrating radar (GPR) is a geophysical technique widely used to study the shallow subsurface and identify various sediment features that reflect electromagnetic waves. However, little is known about the exact cause of GPR reflections because few studies have coupled wave theory to petrophysical data. In this study, a 100- and 200-MHz GPR survey was conducted on aeolian deposits in a [...]