Preprints
Filtering by Subject: Engineering
Comparison of estimation methods for a nonstationary index-flood model in flood frequency analysis using peaks over threshold
Published: 2019-04-05
Subjects: Civil and Environmental Engineering, Engineering, Other Civil and Environmental Engineering
Accurate estimation of flood frequency is crucial for designing safe infrastructures. To reduce model uncertainty, threshold modeling techniques are often useful in bringing more valuable flood information into the analysis than traditional models based on annual maximum discharges. Due to climatic or anthropogenic causes, changes in flood magnitudes in many parts of the world have been observed [...]
Matlab/R workflows to assess critical choices in Global Sensitivity Analysis using the SAFE toolbox
Published: 2019-04-05
Subjects: Applied Mathematics, Civil and Environmental Engineering, Computer Sciences, Earth Sciences, Engineering, Environmental Sciences, Physical Sciences and Mathematics, Risk Analysis, Statistics and Probability
Global Sensitivity Analysis (GSA) is a set of statistical techniques to investigate the effects of the uncertainty in the input factors of a mathematical model on the model’s outputs. The value of GSA for the construction, evaluation, and improvement of earth system models is reviewed in a companion paper by Wagener and Pianosi [n.d.]. The present paper focuses on the implementation of GSA and [...]
The vulnerability of tidal flats and multi-channel estuaries to dredging and disposal
Published: 2019-04-05
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geomorphology, Other Civil and Environmental Engineering, Physical Sciences and Mathematics
Shipping fairways in estuaries are continuously dredged to maintain access for large vessels to major ports. However, several estuaries worldwide show adverse side effects to dredging activities, including a shift from multi-channel systems to single-channel systems and the loss of ecologically valuable intertidal flats. We used a time series of bathymetry of the Western Scheldt estuary (the [...]
Poroelastic effects destabilize mildly rate-strengthening friction to generate stable slow slip pulses
Published: 2019-03-18
Subjects: Applied Mechanics, Earth Sciences, Engineering, Geology, Geophysics and Seismology, Mechanical Engineering, Physical Sciences and Mathematics, Physics, Statistical, Nonlinear, and Soft Matter Physics, Tribology
Slow slip events on tectonic faults, sliding instabilities that never accelerate to inertially limited ruptures or earthquakes, are one of the most enigmatic phenomena in frictional sliding. While observations of slow slip events continue to mount, a plausible mechanism that permits instability while simultaneously limiting slip speed remains elusive. Rate-and-state friction has been successful [...]
Average daily flow of microplastics through a tertiary wastewater treatment plant over a ten-month period
Published: 2019-03-12
Subjects: Civil and Environmental Engineering, Engineering, Environmental Engineering, Environmental Sciences, Physical Sciences and Mathematics
Microplastics (MPs, <5 mm in size) are classified as emerging contaminants but treatment processes are not designed to remove these small particles. Wastewater treatment systems have been proposed as pathways for MPs pollution to receiving waters but quantitative and qualitative data on MP occurrence and transport remains limited, hindering risk assessment and regulation. Here, for the first [...]
Machine Learning Reveals the State of Intermittent Frictional Dynamics in a Sheared Granular Fault
Published: 2019-03-05
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geophysics and Seismology, Geotechnical Engineering, Physical Sciences and Mathematics
The seismogenic plate boundaries are presumed to behave similarly to a densely packed granular medium, where fault and blocks systems rapidly rearrange the distribution of forces within themselves, as particles do in slowly sheared granular systems. We use machine learning and show that statistical features of velocity signals from individual particles in a simulated sheared granular fault [...]
Hydrodynamic control of gas-exchange velocity in small streams
Published: 2019-03-02
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Fluid Dynamics, Hydraulic Engineering, Physical Sciences and Mathematics, Physics, Planetary Sciences
Gas exchange is a critical component of any biogeochemical mass balance model of dissolved gases in aquatic systems, yet the magnitude and drivers of spatial and temporal variations of air-water exchange rates in shallow streams are poorly understood. We investigated the relationships between gas exchange velocity of carbon dioxide and methane and flow hydraulics at different sections along a [...]
Lithological, petrophysical and seal properties of mass-transport complexes (MTCs), northern Gulf of Mexico
Published: 2019-02-22
Subjects: Earth Sciences, Engineering, Engineering Science and Materials, Geology, Physical Sciences and Mathematics, Sedimentology
Mass transport complexes (MTCs) are one of the most sedimentologically and seismically distinctive depositional elements in deep-water depositional systems. Seismic reflection data provide spectacular images of their structure, size, and distribution, although a lack of borehole data means there is limited direct calibration between MTC lithology and petrophysical expression, or knowledge of how [...]
Heavy rainfall in Paraguay during the 2015-2016 austral summer: causes and sub-seasonal-to-seasonal predictive skill
Published: 2019-02-11
Subjects: Atmospheric Sciences, Civil and Environmental Engineering, Climate, Earth Sciences, Engineering, Environmental Engineering, Environmental Sciences, Hydrology, Meteorology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Water Resource Management
During the austral summer 2015/16, severe flooding displaced over 170 000 people on the Paraguay River system in Paraguay, Argentina, and southern Brazil. These floods were driven by repeated heavy rainfall events in the lower Paraguay River basin. Alternating sequences of enhanced moisture inflow from the South American low-level jet and local convergence associated with baroclinic systems were [...]
Factor Analysis by R Programming to Assess Variability Among Environmental Determinants of the Mariana Trench
Published: 2019-01-28
Subjects: Computer Sciences, Earth Sciences, Education, Engineering, Environmental Monitoring, Environmental Sciences, Environmental Studies, Geographic Information Sciences, Geography, Geology, Geomorphology, Geophysics and Seismology, Graphics and Human Computer Interfaces, Life Sciences, Marine Biology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Other Earth Sciences, Other Geography, Other Oceanography and Atmospheric Sciences and Meteorology, Physical and Environmental Geography, Physical Sciences and Mathematics, Programming Languages and Compilers, Remote Sensing, Science and Mathematics Education, Sedimentology, Social and Behavioral Sciences, Spatial Science, Tectonics and Structure, Water Resource Management
The aim of this work is to identify main impact factors affecting variations in the geomorphology of the Mariana Trench which is the deepest place of the Earth, located in the west Pacific Ocean: steepness angle and structure of the sediment compression. The Mariana Trench presents a complex ecosystem with highly interconnected factors: geology (sediment thickness and tectonics including four [...]
Topology, homogeneity and scale factors for object detection: application of eCognition software for urban mapping using multispectral satellite image
Published: 2019-01-25
Subjects: Computer Sciences, Earth Sciences, Education, Educational Methods, Engineering, Environmental Education, Environmental Monitoring, Environmental Sciences, Environmental Studies, Geographic Information Sciences, Geography, Graphics and Human Computer Interfaces, International and Area Studies, Life Sciences, Natural Resources Management and Policy, Other Computer Sciences, Other Earth Sciences, Other Environmental Sciences, Other Physical Sciences and Mathematics, Physical and Environmental Geography, Physical Sciences and Mathematics, Remote Sensing, Science and Mathematics Education, Social and Behavioral Sciences, Spatial Science, Sustainability
The research scope of this paper is to apply spatial object based image analysis (OBIA) method for processing panchromatic multispectral image covering study area of Brussels for urban mapping. The aim is to map different land cover types and more specifically, built-up areas from the very high resolution (VHR) satellite image using OBIA approach. A case study covers urban landscapes in the [...]
Utilising the flexible generation potential of tidal range power plants to optimise economic value
Published: 2019-01-08
Subjects: Civil and Environmental Engineering, Computational Engineering, Engineering, Hydraulic Engineering, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Tidal range renewable power plants have the capacity to deliver predictable energy to the electricity grid, subject to the known variability of the tides. Tidal power plants inherently feature advantages that characterise hydro-power more generally, including a lifetime exceeding alternative renewable energy technologies and relatively low Operation & Maintenance costs. Nevertheless, the [...]
A test case for application of convolutional neural networks to spatio-temporal climate data: Re-identifying clustered weather patterns
Published: 2019-01-01
Subjects: Applied Mathematics, Computer Sciences, Earth Sciences, Engineering, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Planetary Sciences
Convolutional neural networks (CNNs) can potentially provide powerful tools for classifying and identifying patterns in climate and environmental data. However, because of the inherent complexities of such data, which are often spatio-temporal, chaotic, and non-stationary, the CNN algorithms must be designed/evaluated for each specific dataset and application. Yet to start, CNN, a supervised [...]
Land surface temperature estimation at the global scale using satellite observations
Published: 2018-12-19
Subjects: Ecology and Evolutionary Biology, Electrical and Computer Engineering, Engineering, Life Sciences, Physical Sciences and Mathematics
Aim of this paper is to offer a brief overview of satellite based LST estimation fundamentals, discuss the main design principles of the corresponding algorithms, present some examples of the global scale LST and land surface emissivity products from the literature that were derived using satellite observations, and finally highlight different challenges in the described measurement process. [...]
Intensity-Duration-Frequency curves at the global scale
Published: 2018-12-18
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Hydraulic Engineering, Hydrology, Meteorology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Water Resource Management
Intensity-Duration-Frequency (IDF) curves usefully quantify extreme precipitation over various durations and return periods for engineering design. Unfortunately, sparse, infrequent or short observations hinder the creation of robust IDF curves in many locations. This paper presents the first global, multi-temporal (1 to 360 hours) dataset of Generalized Extreme Value (GEV) parameters at 31 km [...]