Preprints
Filtering by Subject: Oceanography and Atmospheric Sciences and Meteorology
A Statistical Evaluation of WRF-LES Trace Gas Dispersion Using Project Prairie Grass Measurements
Published: 2020-08-17
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
In recent years, new measurement systems have been deployed to monitor and quantify methane emissions from the natural gas sector. Large-eddy simulation (LES) has complemented measurement campaigns by serving as a controlled environment in which to study plume dynamics and sampling strategies. However, with few comparisons to controlled-release experiments, the accuracy of LES for modeling [...]
Changes in temperature and rainfall extremes across East Asia in the CMIP5 ensemble
Published: 2020-07-22
Subjects: Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
We analyze annual extremes of daily maximum and minimum surface air temperature and of daily rainfall in East Asia and the Korean peninsula. This study made intensive use of the simulation data available from the CMIP5 (Coupled Model intercomparison Project Phase 5) multimodels in historical and future experiments up to year 2100, employing three different radiative forcings: RCP2.6, RCP4.5, [...]
A general expression for wave-induced sediment bypassing of an isolated headland
Published: 2020-07-21
Subjects: Earth Sciences, Engineering, Geomorphology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Other Engineering, Physical Sciences and Mathematics
Accurate knowledge of the sediment budget of a coastal cell is necessary for coastal management and predicting long-term coastal change. An important component in the sediment budget of many wave-dominated embayed coastlines is the amount of sediment that bypasses rocky headlands, which present partial barriers to alongshore transport. Despite a recent surge in research interest in headland [...]
An Eddy-Zonal Flow Feedback Model for Propagating Annular Modes
Published: 2020-07-20
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The variability of the zonal-mean large-scale extratropical circulation is often studied using individual modes obtained from empirical orthogonal function (EOF) analyses. The prevailing reduced-order model of the leading EOF (EOF1) of zonal-mean zonal wind, called the annular mode, consists of an eddy-mean flow interaction mechanism that results in a positive feedback of EOF1 onto itself. [...]
Modelling an energetic tidal strait: investigating implications of common numerical configuration choices
Published: 2020-07-16
Subjects: Applied Mathematics, Civil and Environmental Engineering, Civil Engineering, Engineering, Numerical Analysis and Computation, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Characterising tidal hydrodynamics in the vicinity of submerged features can be demanding given the hostility of the marine environment. Logistical challenges in the measurement of such flows has promoted research on wake studies through physical and numerical modelling. In this study, site measurements and modelled data are combined to provide an insight into the regional hydrodynamics within a [...]
Rapid heat discharge during deep-sea eruptions generates megaplumes and disperses tephra
Published: 2020-07-16
Subjects: Earth Sciences, Fluid Dynamics, Geology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics, Physics, Volcanology
Deep-marine volcanism drives Earth’s most energetic transfers of heat and mass between the crust and the oceans. Seafloor magmatic activity has been correlated in time with the appearance of massive enigmatic plumes of hydrothermal fluid, known as megaplumes, yet little is known of the primary source and intensity of the hydrothermal energy release that occurs during [...]
Variational Ensemble-Transform Filtering of HFR & ADCP velocities in the ice-free Chukchi Sea
Published: 2020-07-15
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Other Oceanography and Atmospheric Sciences and Meteorology, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics
The Chukchi Sea (CS) is the gateway to the Arctic Ocean (AO) for Pacific waters entering from Bering Strait (BS) and also a potential location for future offshore oil extraction. Since 2010, regional CS data has become more plentiful with acoustic Doppler current profilers (ADCP) moored throughout the northwestern portion of the shelf along with coastal high-frequency radar (HFR) surface [...]
Alkenone isotopes show evidence of active carbon concentrating mechanisms in coccolithophores as aqueous carbon dioxide concentrations fall below 7 µmolL-1
Published: 2020-07-15
Subjects: Biogeochemistry, Climate, Earth Sciences, Geochemistry, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Coccolithophores and other haptophyte algae acquire the carbon required for metabolic processes from the water in which they live. Whether carbon is actively moved across the cell membrane via a carbon concentrating mechanism, or passively through diffusion, is important for haptophyte biochemistry. The possible utilisation of carbon concentrating mechanisms also has the potential to overprint [...]
Forecasting the localized bilateral effects of ocean acidification on the counter carbonate pump using recurrent neural networks
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
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 [...]
Mass independent fractionation of even and odd mercury isotopes during atmospheric mercury redox reactions
Published: 2020-07-08
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Mass independent fractionation (MIF) of even mass number mercury (Hg) stable isotopes is observed in rainfall and gaseous elemental Hg0 globally, and is used to quantify atmospheric Hg deposition pathways. The chemical reaction and underlying even-Hg MIF mechanism are unknown however, and speculated to be caused by Hg photo-oxidation on aerosols at the tropopause. Here we investigate the Hg [...]
Surprising Changes in Aerosol Loading over India Amid COVID-19 Lockdown
Published: 2020-07-06
Subjects: Atmospheric Sciences, Climate, Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Using ground-based and satellite observation along with aerosol reanalysis products, we show a widespread reduction in aerosol loading over the Indian subcontinent during the COVID-19 (COronaVIrus Disease 2019) lockdown. The pre-lockdown and lockdown period considered in the present study is 20th February–20th March 2020 and 24th March–22nd April 2020. In terms of aerosol optical depth (AOD), [...]
Deep spatial transformers for autoregressive data-driven forecasting of geophysical turbulence
Published: 2020-07-05
Subjects: Artificial Intelligence and Robotics, Atmospheric Sciences, Climate, Computer Sciences, Dynamical Systems, Earth Sciences, Environmental Sciences, Fluid Dynamics, Geophysics and Seismology, Mathematics, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Physics
A deep spatial transformer based encoder-decoder model has been developed to autoregressively predict the time evolution of the upper layers stream function of a two-layered quasi-geostrophic (QG) system without any information about the lower layers stream function. The spatio-temporal complexity of QG flow is comparable to the complexity of 500hPa Geopotential Height (Z500) of fully coupled [...]
Ekman-Inertial Instability
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
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 [...]