Preprints
There are 5725 Preprints listed.
A mixed $RT_0 - P_0$ Raviart-Thomas finite element implementation of Darcy Equation in GNU Octave
Published: 2020-04-13
Subjects: Applied Mathematics, Bioresource and Agricultural Engineering, Chemical Engineering, Computational Engineering, Earth Sciences, Engineering, Environmental Sciences, Hydrology, Numerical Analysis and Computation, Partial Differential Equations, Physical Sciences and Mathematics, Water Resource Management
In this paper we shall describe mixed formulations -differential and variational- of Darcys flow equation, an important model of elliptic problem. We describe * Galerkin method with finite dimensional spaces; * Local matrices and assembling; * Raviart-Thomas $RT_0 - P_0$ elements; * Edge basis and local matrices for $RT_0 - P_0$ FEM; * Model problem with corresponding local matrices, right hand [...]
Machine Learning on Greenest Pixels for Crop Mapping
Published: 2020-04-13
Subjects: Geography, Remote Sensing, Social and Behavioral Sciences
Remotely sensed signals from crop fields are full of variabilities due to the complex interactions among the environment, seeds, climate, market, and farmers. It is a common phenomenon that the crops in neighbouring fields are in different growing stages, e.g., the corns are in the V5 leaf stage in one field and V10 stage in another neighbouring field. The phenomenon results in remote sensing [...]
SymAE: an autoencoder with embedded physical symmetries for passive time-lapse monitoring
Published: 2020-04-13
Subjects: Applied Mathematics, Computer Sciences, Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
We introduce SymAE, an auto-encoder architecture that learns to separate multichannel passive-seismic datasets into qualitatively interpretable components: one component corresponds to path-specific effects associated with subsurface properties while the other component corresponds to the spectral signature of the passive sources. This information is represented by two latent codes produced by [...]
Enhanced secondary pollution offset reduction of primary emissions during COVID-19 lockdown in China
Published: 2020-04-13
Subjects: Atmospheric Sciences, Environmental Health and Protection, Environmental Monitoring, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
To control the spread of the 2019 novel coronavirus (COVID-19), China imposed nationwide restrictions on the movement of its population (lockdown) after the Chinese New Year of 2020, leading to large reductions in economic activities and associated emissions. Despite such large decreases in primary pollution, there were nonetheless several periods of heavy haze pollution in East China, raising [...]
Success at the farm-level in payments for ecosystem services: monetary incentives, participatory processes and institutional adaptation all matter
Published: 2020-04-13
Subjects: Earth Sciences, Environmental Sciences, Life Sciences, Natural Resources and Conservation, Physical Sciences and Mathematics
While payments for ecosystem services (PES) schemes are increasingly common, in most cases, their effectiveness has lagged behind initial expectations. A major debate exists around whether performance can be improved by prioritising project design features that align with the theoretical, economistic model of PES, or whether, where necessary, it is more important for projects to depart from this [...]
Social as much as environmental: the drivers of tree biomass in smallholder forest landscape restoration programmes
Published: 2020-04-13
Subjects: Environmental Sciences, Life Sciences, Natural Resources and Conservation, Physical Sciences and Mathematics
A major challenge for forest landscape restoration initiatives is the lack of quantitative evidence on how social factors drive environmental outcomes. Here we conduct a transdisciplinary quantitative analysis of the environmental and social drivers of tree biomass accumulation across 639 smallholder farms restoring native tree species in Mexico, Uganda and Mozambique. We use environmental and [...]
Cascading Failure Phenomenon in the Multi-Stage Hydraulically Fractured Wells
Published: 2020-04-13
Subjects: Environmental Sciences, Oil, Gas, and Energy, Physical Sciences and Mathematics
The phenomenon of cascading fracture failure during flowback and initial production from a horizontal multistage hydraulically fractured well is introduced, described, and investigated. First, a simplified analytical model of production from such well is built. This model allows evaluating a range of systems parameters through which the cascading failure evolves and performing a sensitivity study [...]
Weak influence of paleoenvironmental conditions on the subsurface biosphere of lake Ohrid in the last 515 ka
Published: 2020-04-13
Subjects: Earth Sciences, Environmental Microbiology and Microbial Ecology Life Sciences, Environmental Sciences, Life Sciences, Microbiology, Other Earth Sciences, Paleobiology, Physical Sciences and Mathematics
Understanding the response of geo- and biosystems to past climatic disturbance is primordial to assess the short to long terms effects of current global change. Lacustrine sediments are commonly used to investigate the impact of climatic change on biogeochemical cycling. In these sediments, subsurface microbial communities play a primordial role in nutrient, organic matter and elemental cycling, [...]
Global heat uptake by inland waters
Published: 2020-04-12
Subjects: Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics
Heat uptake is a key variable for understanding the Earth system response to greenhouse gas forcing. Despite the importance of this heat budget, heat uptake by inland waters has so far not been quanti?ed. Here we use a unique combination of global-scale lake models, global hydrological models and Earth system models to quantify global heat up take by natural lakes, reservoirs and rivers. The [...]
A new approach to inferring basal drag and ice rheology in ice streams, with applications to West Antarctic ice streams
Published: 2020-04-12
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Drag at the bed and along the lateral margins are the primary forces resisting flow in outlet glaciers. Simultaneously inferring these parame- ters is challenging since basal drag and ice viscosity are coupled in the momen- tum balance, which governs ice flow. Here, we test the ability of adjoint-based inverse methods to infer the slipperiness coefficient in a power-law sliding law and the [...]
Aquifer deformation and active faulting in Salt Lake Valley, Utah, USA
Published: 2020-04-12
Subjects: Earth Sciences, Geophysics and Seismology, Hydrology, Physical Sciences and Mathematics
Aquifers and fault zones may interact through groundwater flow and stress redistribution, yet their spatiotemporal relationship remains enigmatic. Here we quantify changes in water storage and associated stress along the Wasatch Fault Zone in Salt Lake Valley, recently shaken by a M5.7 earthquake on March 18th, 2020. Ground deformation mapped by Sentinel-1 SAR imagery (2014-2019) reveals an [...]
InSAR Time Series Analysis of L-band Wide- Swath SAR Data Acquired by ALOS-2
Published: 2020-04-12
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Environmental Sciences, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mining Engineering, Other Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Operating at L-band (~24 cm wavelength) in wide-swath modes is one of the characteristics of the new and next generation satellite synthetic aperture radar (SAR) missions. After 3 years of operation, the Japan Aerospace Exploration Agency Advanced Land Observing Satellite-2 (ALOS-2) satellite has acquired a wealth of L-band wide-swath SAR data over many areas using its ScanSAR mode. We present [...]
Fault seal modelling – the influence of fluid properties on fault sealing capacity in hydrocarbon and CO2 systems
Published: 2020-04-12
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Fault seal analysis is a key part of understanding the hydrocarbon trapping mechanisms in the petroleum industry. Fault seal research has also been expanded to CO2-brine systems for the application to Carbon Capture and Storage (CCS). The wetting properties of rock-forming minerals in the presence of hydrocarbons or CO2 are a source of uncertainty in the calculations of capillary threshold [...]
Concepts of space, time and scale
Published: 2020-04-11
Subjects: Forest Sciences, Geographic Information Sciences, Geography, Life Sciences, Social and Behavioral Sciences
Concepts of space, time and scale as well as their underpinning theories are crucial for understanding geospatial data. Space can be defined as a boundless, three-dimensional (3D) extent in which objects and events occur and have relative position and direction. Space has been considered to be absolute, meaning that it exists permanently and independently regardless of any matter in space. [...]
Fundamental laws and principles in geoinformation science
Published: 2020-04-11
Subjects: Forest Sciences, Geographic Information Sciences, Geography, Life Sciences, Social and Behavioral Sciences
Scientific laws are empirical statements, based on repeated experiments or observations, that describe or predict a range of natural phenomena. There are scientific laws and law-like statements also in the field of geoinformation sciences. Based on the Tobler’s first law of geography, “everything is related to everything else, but near things are more related than distant things”. This first law [...]