Preprints
Filtering by Subject: Physical Sciences and Mathematics
Stronger Atlantic hurricanes: Validating Elsner et al. (2008)
Published: 2019-12-04
Subjects: Climate, Earth Sciences, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Using satellite derived wind speed estimates from tropical cyclones over the 25-year period 1981--2006, Elsner et al. (2008) showed the strongest tropical cyclones getting stronger. They related the increasing intensity to rising ocean temperatures consistent with theory. Oceans continued to warm since that paper was published so the intensity of the strongest cyclones should have continued [...]
Estimation of surface and deep flows from sparse SSH observations of geostrophic ocean turbulence using Deep Learning
Published: 2019-12-04
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Satellite altimeters provide global observations of sea surface height (SSH) and present a unique dataset for advancing our theoretical understanding of upper ocean dynamics and monitoring its variability. Considering that mesoscale SSH patterns of 50--300 km in size can evolve on timescales comparable to or shorter than satellite return periods, it is challenging to accurately reconstruct the [...]
A machine learning approach to tungsten prospectivity modelling using knowledge-driven feature extraction and model confidence
Published: 2019-12-04
Subjects: Earth Sciences, Geology, Other Earth Sciences, Physical Sciences and Mathematics
Novel mineral prospectivity modelling presented here applies knowledge-driven feature extraction to a data-driven machine learning approach for tungsten mineralisation. The method emphasises the importance of appropriate model evaluation and develops a new Confidence Metric to generate spatially refined and robust exploration targets. The data-driven Random Forest™ algorithm is employed to model [...]
An interpreted language implementation of the Vaganov-Shashkin tree-ring proxy system model
Published: 2019-12-04
Subjects: Climate, Earth Sciences, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
We describe the implementation of the Vaganov-Shashkin tree-ring growth model (VSM) in MATLAB. VSM, originally written in Fortran, mimics subdaily and daily resolution processes of cambial growth as a function of soil moisture, air temperature, and insolation, with environmental forcing modeled as the principle of limiting factors. The re-implementation in a high level interpreted language, [...]
Evaluation and comparison of a machine learning cloud identification algorithm for the SLSTR in polar regions
Published: 2019-12-04
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
A Feed Forward Neural Net (NN) approach to distinguish between clouds and the surface has been applied to the Sea and Land Surface Temperature Radiometer in polar regions. The masking algorithm covers the Arctic, Antarctic and regions typically classified as the cryosphere such as northern hemisphere permafrost. The mask has been trained using collocations with the CALIOP active lidar, which in [...]
Climate driven Holocene erosion in central Ukraine
Published: 2019-12-04
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
The younger Quaternary erosion history was reconstructed in a catchment close to the Chalcolithic giant settlement Maidanetske, central Ukraine based on dated sediment sequences. Four trenches and a long percussion drill-core were analyzed in a valley grading from a Loess covered plateau towards the Talianky River. The sediments were dated via a combination of radiocarbon dating, optical [...]
Scaling Laws for Regional Stratification at the top of Earth’s Core
Published: 2019-12-04
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Seismic and geomagnetic observations have been used to argue both for and against a global stratified layer at the top of Earth’s outer core. Recently, we used numerical models of turbulent thermal convection to show that imposed lateral variations in core-mantle boundary (CMB) heat flow can give rise to regional lenses of stratified fluid at the top of the core while the bulk of the core remains [...]
Advanced ML and AI Approaches for Proxy-based Optimization of CO2-Enhanced Oil Recovery in Heterogeneous Clastic Reservoirs
Published: 2019-12-04
Subjects: Artificial Intelligence and Robotics, Computer Sciences, Design of Experiments and Sample Surveys, Earth Sciences, Multivariate Analysis, Other Earth Sciences, Physical Sciences and Mathematics, Programming Languages and Compilers, Statistics and Probability
Constructing a simpler model to represent a complex reservoir simulation that will be employed to define the optimum future development plans have been achieved through the use of different simulation techniques that include EOS-compositional reservoir simulation, Proxy Modeling as well as Design of Experiments. Once reliable history matching was achieved, the key five operational decision [...]
Quantifying Computational Efficiency of Adaptive Mesh Refinement for Shallow Water Solvers
Published: 2019-12-04
Subjects: Computer Sciences, Numerical Analysis and Scientific Computing, Physical Sciences and Mathematics
Non-uniform, dynamically adaptive meshes are a useful tool for reducing computational complexities for geophysical simulations that exhibit strongly localised features such as is the case for example for tsunami, hurricane or typhoon prediction. Theoretical insight for mesh-based numerical methods, however, is largely restricted to uniform meshes as they allow for a traditional definition of [...]
Spatiotemporal correlation analysis of noise-derived seismic body waves with ocean wave climate and microseism sources
Published: 2019-12-04
Subjects: Earth Sciences, Geophysics and Seismology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Seismic signals can be extracted from ambient noise wavefields by the correlation technique. Recently, a prominent P‐type phase was observed from teleseismic noise correlations in the secondary microseism period band. The phase is named Pdmc in this paper, corresponding to its origin from the interference between the direct P waves transmitting through the deep mantle and the core (P and PKPab [...]
Dreibrodt et al.- Holocene erosion history in central Ukraine
Published: 2019-12-04
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
The younger Quaternary erosion history was reconstructed in a catchment close to the Chalcolithic giant settlement Maidanetske, central Ukraine based on dated sediment sequences. Four trenches and a long percussion drill-core were analyzed in a valley grading from a Loess covered plateau towards the Talianky River. The sediments were dated via a combination of radiocarbon dating, optical [...]
No support for carbon storage of >1000 GtC in northern peatlands
Published: 2019-12-04
Subjects: Biogeochemistry, Earth Sciences, Physical Sciences and Mathematics
Northern peatlands store large amounts of carbon (C) and have played an important role in the global carbon cycle since the Last Glacial Maximum. Most northern peatlands have established since the end of the deglaciation and accumulated C over the Holocene, leading to a total present-day stock of 500 ± 100 GtC. This is a consolidated estimate, emerging from a diversity of methods. Recently, [...]
Local and remote influences on the heat content of Southern Ocean mode water formation regions.
Published: 2019-12-04
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The Southern Ocean (SO) is a crucial region for the global ocean uptake of heat and carbon. There are large uncertainties in the observations of fluxes of heat and carbon between the atmosphere and the ocean mixed layer, which leads to large uncertainties in the amount entering into the global overturning circulation. In order to better understand where and when fluxes of heat and momentum have [...]
Accelerating numerical wave-propagation using wavefield adapted meshes, Part I: Forward and adjoint modelling
Published: 2019-12-04
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
An order of magnitude speed-up in finite-element modelling of wave propagation can be achieved by adapting the mesh to the anticipated space-dependent complexity and smoothness of the waves. This can be achieved by designing the mesh not only to respect the local wavelengths, but also the propagation direction of the waves depending on the source location, hence by anisotropic adaptive mesh [...]
The economic implications of using a truly preindustrial climate baseline
Published: 2019-12-04
Subjects: Climate, Geography, Human Geography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Social and Behavioral Sciences
The pervasive impacts of climate change can result in scientific decisions having unforeseen societal implications. To demonstrate this, we explore the global and regional economic implications of adopting an earlier preindustrial baseline of 1400-1800 for climate policy targets instead of the commonly used early industrial period of 1850-1900 for which we have observational data. Because of [...]