Preprints

Filtering by Subject: Oceanography

Forecasting the localized bilateral effects of ocean acidification on the counter carbonate pump using recurrent neural networks

Eshan Ramesh

Published: 2020-07-08
Subjects: Artificial Intelligence and Robotics, Chemistry, Computer Sciences, Environmental Chemistry, Numerical Analysis and Scientific Computing, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

The counter carbonate pump(CCP) is responsible for carbon dioxide sequestration and cycling forms of carbon in the ocean. It is primarily driven by calcifying plankton, such as foraminifera, coccolithophores, and pteropods. These organisms are particularly vulnerable to ocean acidification, which can have disastrous effects on their skeletons and productivity, upsetting the marine carbon cycle in [...]

Application of the tilt derivative transform to bathymetric data for structural lineament mapping

Christopher Mark Yeomans, Matthew Head, Jordan James Lindsay

Published: 2020-07-08
Subjects: Computer Sciences, Earth Sciences, Geomorphology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Tectonics and Structure

High-resolution bathymetry surveys provide an opportunity to analyse local geological structure where onshore areas afford limited exposure. Semi-automated lineament detection methods are necessary for areas of large coverage where a manual analysis would be subjective and time-consuming. However, semi-automated approaches are dependent on effective feature extraction methods to identify genuine [...]

Ekman-Inertial Instability

Nicolas Grisouard, Varvara E. Zemskova

Published: 2020-07-05
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

We report on an instability, arising in sub-surface, laterally-sheared flows in rotation. When the lateral shear of a horizontal flow in geostrophic balance is of opposite sign as the Coriolis parameter, and exceeds it in magnitude, embedded perturbations are subjected to inertial instability, albeit modified by viscosity. When the perturbation arises from the surface of the fluid, the initial [...]

Adjoint-based sensitivity analysis for a numerical storm surge model

Simon Charles Warder, Kevin Horsburgh, Matthew Piggott

Published: 2020-06-29
Subjects: Applied Mathematics, Numerical Analysis and Computation, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

Numerical storm surge models are essential to forecasting coastal flood hazard and informing the design of coastal defences. However, such models rely on a variety of inputs, many of which will carry uncertainty, and an awareness and understanding of the sensitivity of the model outputs with respect to those uncertain inputs is necessary when interpreting model results. Here, we use an [...]

A comparison of Bayesian inference and gradient-based approaches for friction parameter estimation

Simon Charles Warder, Athanasios Angeloudis, Stephan C. Kramer, et al.

Published: 2020-06-29
Subjects: Applied Mathematics, Numerical Analysis and Computation, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

Numerical tidal models are essential to the study of a variety of coastal ocean processes, but typically rely on uncertain inputs, including a bottom friction parameter which can in principle be spatially varying. Here we employ an adjoint-capable numerical ocean model, Thetis, and apply it to the Bristol Channel and Severn Estuary, using a spatially varying Manning coefficient within the bottom [...]

Tropical cyclone response to anthropogenic warming as simulated by a mesoscale-resolving global coupled earth system model

Axel Timmermann, Jung-Eun Chu, Sun-Seon Lee, et al.

Published: 2020-06-19
Subjects: Atmospheric Sciences, Climate, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

Tropical cyclones (TCs) are extreme storm systems that form over warm tropical oceans. Along their track TCs can mix up cold water which can further impact their development. Due to the adoption of lower ocean model resolutions, previous modeling studies on the TC response to greenhouse warming underestimate such oceanic feedbacks. To address the robustness of TC projections in the presence of [...]

Global wave-driven beach evolution; consequences for observation strategies

Erwin Bergsma, Rafael Almar, Thierry Garlan, et al.

Published: 2020-06-12
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Life Sciences, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

It is an illusion to think that one can observe monthly beach behaviour with monthly surveys. Current coastal observation strategies restrict understanding of beach evolution, preventing effective risk mitigation. In this article, we quantify the global spatiotemporal scales of coastal wave changes, which are the known dominant driver of beach evolution. Consequences and recommendations for beach [...]

A novel rules-based shoreface translation model for predicting future coastal change: ShoreTrans

Robert Jak McCarroll, Gerd Masselink, Nieves G. Valiente, et al.

Published: 2020-06-05
Subjects: Earth Sciences, Engineering, Geomorphology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Other Engineering, Physical Sciences and Mathematics

Predicting change to global shorelines presents an increasing challenge as sea-level rise (SLR) accelerates. Many shoreline prediction models use variations of the ‘Bruun-rule’, failing to account for relevant processes and morphologic complexity. To address this, we introduce a simple rules-based model (ShoreTrans) designed for complex, real-world profiles that predicts change across a wide [...]

Advective sorting of silt by currents: a laboratory study

Jeff Culp, Kyle Strom, Andrew Parent, et al.

Published: 2020-05-28
Subjects: Earth Sciences, Geomorphology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sedimentology

Accumulations of fine sediments along continental shelf and deep-sea bathymetric contours, known as contourite drifts, form a sedimentary record that is dependent on oceanographic processes such as ocean-basin-scale circulation. A tool used to aid in interpretation of such deposits is the sortable silt hypothesis, which suggests that the mean size of the sortable silt (silt from 10-63 µm) within [...]

Kilometer-scale sound speed structure that affects GNSS-A observation: Case study off the Kii channel

Yusuke Yokota, Tadashi Ishikawa, Shun-ichi Watanabe, et al.

Published: 2020-05-28
Subjects: Earth Sciences, Geophysics and Seismology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

The Global Navigation Satellite System-Acoustic ranging combination technique (GNSS-A) is a recently developed technology to precisely detect seafloor crustal deformation. This method can also estimate km-scale underwater sound speed structure (SSS) as a by-product of monitoring seafloor crustal deformation. This paper evaluates the validity of the spatial gradient and its temporal variation of [...]

Recent water mass changes reveal mechanisms of ocean warming

Jan David Zika, Jonathan Gregory, Elaine McDonagh, et al.

Published: 2020-05-19
Subjects: Climate, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

Over 90% of the build up of additional heat in the earth system over recent decades is contained in the ocean. Since 2006 new observational programs have revealed heterogeneous patterns of ocean heat content change. It is unclear how much of this heterogeneity is due to heat being added to and mixed within the ocean leading to material changes in water mass properties or due to changes in [...]

Human Health Benefits of the Minamata Convention on Mercury

Yanxu Zhang, Stephanie Dutkiewicz, Huanxin Zhang, et al.

Published: 2020-05-17
Subjects: Atmospheric Sciences, Biogeochemistry, Climate, Earth Sciences, Environmental Health and Protection, Environmental Sciences, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

The Minamata Convention is a legally-binding international treaty aimed at reducing the anthropogenic release of mercury, a potent neurotoxin. However, its human health benefit has not been quantified on a global scale. Here we evaluate the Convention’s benefit by a coupled climate-atmosphere-land-ocean-ecosystem model and a human mercury exposure component that considers all food categories. We [...]

Projections of global delta land loss from sea-level rise in the 21st century

Jaap H. Nienhuis

Published: 2020-05-06
Subjects: Earth Sciences, Geomorphology, Hydrology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sedimentology

River deltas will likely experience significant land loss because of relative sea-level rise (RSLR), but predictions have not been tested against observations. Here, we use global data of RSLR and river sediment supply to build a model of delta response to RSLR for 6,402 deltas, representing 86% of global delta land. We validate this model against delta land area change observations from [...]

Unexpected meteotsunamis prior to the Typhoon Wipha

Li-Ching Lin, Chin H. Wu

Published: 2020-03-24
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

On October 15, 2013, unexpected meteotsunamis occurred prior to Typhoon Wipha located the distance of ~1,100 km from the center of the cyclone to the Tokyo bay. The occurrences were observed around the east coast of Japan coincidentally with atmospheric pressure disturbances induced by this typhoon. The observed wave height of meteotsunamis was up to ~0.5 m with the pressure fluctuation of ~2 hPa [...]

Rapid Tidal Marsh Development in Anthropogenic Backwaters

Brian Yellen, Jonathon Woodruff, David Ralston, et al.

Published: 2020-03-21
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Fresh Water Studies, Geomorphology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sustainability, Water Resource Management

Tidal marsh restoration and creation has been proposed as a tool to build coastal resilience in the face of rising sea level and increasing intensity of coastal storms. However, it is unclear what conditions within constructed settings will lead to the successful establishment of tidal marsh. We used sediment cores and historical geospatial data in the tidal freshwater Hudson River to identify [...]

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