Preprints
Filtering by Subject: Oceanography
CO2 capture by pumping surface acidity to the deep ocean
Published: 2021-04-30
Subjects: Chemical Engineering, Climate, Engineering, Environmental Engineering, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The majority of IPCC scenarios call for active CO2 removal (CDR) to remain below 2oC of warm- ing. On geological timescales, ocean uptake regulates atmospheric CO2 concentration, with two homeostats driving CO2 uptake: dissolution of deep ocean calcite deposits and terrestrial weathering of silicate rocks, acting on 1ka to 100ka timescales, respectively. Many current ocean-based CDR proposals [...]
Note on the bulk estimate of the energy dissipation rate in the oceanic bottom boundary layer
Published: 2021-04-26
Subjects: Oceanography, Physical Sciences and Mathematics
The dissipation of the kinetic energy (KE) associated with oceanic flows is believed to occur primarily in the oceanic bottom boundary layer (BBL) where bottom drag converts the KE from mean flows to heat loss through irreversible mixing at molecular scales. Due to the practical difficulties associated with direct observations on small-scale turbulence close to the seafloor, most up-to-date [...]
Optimal experiment design for bottom friction parameter estimation
Published: 2021-04-23
Subjects: Design of Experiments and Sample Surveys, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
It is common practice within numerical coastal ocean modelling to perform model calibration with respect to a bottom friction parameter. While many modelling studies employ a spatially uniform coefficient, within the parameter estimation literature the coefficient is typically taken to be spatially (or even temporally) varying. A parameter estimation experiment requires an appropriate set of [...]
A deep-learning estimate of the decadal trends in the Southern Ocean carbon storage
Published: 2021-04-21
Subjects: Atmospheric Sciences, Biogeochemistry, Climate, Earth Sciences, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Uptake of atmospheric carbon by the ocean, especially at high latitudes, plays an important role in offsetting anthropogenic emissions. At the surface of the Southern Ocean south of 30◦S, the ocean carbon uptake, which had been weakening in 1990s, strengthened in the 2000s. However, sparseness of in-situ measurements in the interior make it difficult to compute changes in carbon storage below [...]
A simplified palaeoceanography archiving system (PARIS) and GUI for storage and visualisation of marine sediment core proxy data vs age and depth.
Published: 2021-04-14
Subjects: Climate, Earth Sciences, Oceanography
Scientific discovery can be aided when data is shared following the principles of findability, accessibility, interoperability, reusability (FAIR) data (Wilkinson et al., 2016). Recent discussions in the palaeoclimate literature have focussed on defining the ideal database format for storing data and associated metadata. Here, we highlight an often overlooked primary process in widespread [...]
BENTHIC NUTRIENT FLUXES ACROSS A PRODUCTIVE SHELF ADJACENT TO AN OLIGOTROPHIC BASIN: CASE OF THE NORTHEASTERN MEDITERRANEAN SEA
Published: 2021-04-08
Subjects: Environmental Chemistry, Oceanography
The coastal ecosystem of the Northeastern (NE) Mediterranean has been affected by nutrient inputs originated from regional rivers and wastewater discharges leading to development of eutrophication. Atmospheric nutrient inputs have also remarkable contribution to marine nutrient pool in the NE Mediterranean, especially in dry periods. Sediment porewater nutrient fluxes into the deep waters are [...]
Shallow or deep? A reinterpretation of the Rifian Corridor’s unique sandy contourites
Published: 2021-02-25
Subjects: Climate, Earth Sciences, Geology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Paleontology, Sedimentology, Stratigraphy
This study proposes that sandstone layers exposed in the Fez-Meknes region of Northern Morocco (Ben Allou (Sidi Chaded) and El Adergha localities), have been misinterpreted as unique examples of geostrophically-driven, deep marine (150 - 400 m water depth) sandy contourites. Instead, our independent paleontological, sedimentological, and stratigraphic analyses show that these sandstones represent [...]
High-resolution observations of the North Pacific transition layer from a Lagrangian float
Published: 2021-02-11
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
A crucial region of the ocean surface boundary layer (OSBL) is the strongly-sheared and -stratified transition layer (TL) separating the mixed layer from the upper pycnocline, where a diverse range of waves and instabilities are possible. Previous work suggests that these different waves and instabilities will lead to different OSBL behaviours. Therefore, understanding which physical processes [...]
Modeling and SAR Imaging of the Sea Surface: a Review of the State-of-the-Art with Simulations
Published: 2021-02-10
Subjects: Oceanography
Among other remote sensing technologies, synthetic aperture radar (SAR) has become firmly established in the practice of oceanographic research. Despite solid experience in this field, comprehensive knowledge and interpretation of ocean/sea and vessel wave signatures on radar images are still very challenging. This is not only due to the complex mechanisms involved in the SAR imaging of moving [...]
Dynamical attribution of North Atlantic interdecadal predictability to oceanic and atmospheric turbulence under realistic and optimal stochastic forcing
Published: 2021-02-01
Subjects: Climate, Environmental Sciences, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Unpredictable variations in the ocean originate from both external atmospheric forcing and chaotic processes internal to the ocean itself, and are a crucial sink of predictability on interdecadal timescales. In a global ocean model, we present i.) an optimisation framework to compute the most efficient noise patterns to generate uncertainty and ii.) a uniquely inexpensive, dynamical method for [...]
The active and passive roles of the ocean in generating basin-scale heat content variability
Published: 2021-01-28
Subjects: Climate, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The role of ocean circulation in transforming surface forcing into interannual-to-multidecadal oceanic variability is an area of ongoing debate. Here, a novel method, establishing exact causal links, is used to quantitatively determine the role of ocean active and passive processes in transforming stochastic surface forcing into heat content variability. To this end, we use a global ocean model [...]
Vertical fluxes conditioned on vorticity and strain reveal submesoscale ventilation
Published: 2021-01-24
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology
It has been hypothesized that submesoscale flows play an important role in the vertical transport of climatically important tracers, due to their strong associated vertical velocities. However, the multi-scale, non-linear and Lagrangian nature of transport makes it challenging to attribute proportions of the tracer fluxes to certain processes, scales, regions or features. Here we show that [...]
The Rayleigh-Haring-Tayfun distribution of wave heights in deep water
Published: 2021-01-17
Subjects: Engineering, Fluid Dynamics, Hydraulic Engineering, Oceanography, Statistical Models
Regarding wave statistics, nearly every known exceeding probability distribution applied to rogue waves has shown disagreement with its peers. More often than not, models and experiments have shown a fair agreement with the Rayleigh distribution whereas others show that the latter underpredicts extreme heights by almost one order of magnitude. Virtually all previous results seem to be [...]
Near-inertial dissipation due to stratified flow over abyssal topography
Published: 2021-01-12
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Linear theory for steady stratified flow over topography sets the range for topographic wavenumbers over which freely propagating internal waves are generated, and the radiation and breaking of these waves contribute to energy dissipation away from the ocean bottom. However, previous numerical work demonstrated that dissipation rates can be enhanced by flow over large scale topographies with [...]
Enhanced hydrological cycle increases ocean heat uptake and moderates transient climate sensitivity
Published: 2020-11-25
Subjects: Climate, Oceanography, Oceanography and Atmospheric Sciences and Meteorology
The large-scale moistening of the atmosphere in response to increasing greenhouse gases amplifies the existing patterns of precipitation minus evaporation (P-E) which, in turn, amplifies the spatial contrast in sea surface salinity (SSS). Through a series of CO2 doubling experiments, we demonstrate that surface salinification driven by the amplified dry conditions (P-E < 0), primarily in the [...]