Preprints
Filtering by Subject: Oceanography
An Updated Parametrization of Algorithms to Retrieve the Diffuse Attenuation of Light in the Ocean from Remote Sensing and its Impact on Estimates of Net Primary Productivity
Published: 2023-02-10
Subjects: Climate, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Oil, Gas, and Energy, Other Environmental Sciences
We recently found a significant bias while validating frequently used ocean color algorithms retrieving the spectral diffuse attenuation coefficient (Kd(λ))(Begouen and Boss, 2022). Here we modify existing algorithms for Kd(λ) to remove the observed bias at Kd(490), and evaluate the impact on global and regional estimates of net primary production (NPP) using two different primary production [...]
Sand Shoal Dynamics of a Tide-Dominated Estuarine Embayment: Comparison of a Numerical Sediment Transport Model against Field Observations
Published: 2023-02-07
Subjects: Engineering, Environmental Engineering, Oceanography
This paper presents an innovative and detailed dataset of currents and sediment transport observations over a sand shoal system responsible for focusing wave energy on eroding coastline. The data are used to measure the performance of a detailed numerical sediment transport model of the sand shoal system. The predictive skill of the model is 0.96 for tidal elevations within Port Phillip Bay, 0.75 [...]
Internal gravity waves generated by subglacial discharge: implications for tidewater glacier melt
Published: 2023-02-03
Subjects: Climate, Oceanography
Submarine melting has been implicated in the accelerated retreat of marine-terminating glaciers globally. Energetic ocean flows, such as subglacial discharge plumes, are known to enhance submarine melting in their immediate vicinity. Using observations and a large eddy simulation, we demonstrate that discharge plumes emit high-frequency internal gravity waves that propagate along glacier termini [...]
How fine is fine enough? Effect of mesh resolution on hydrodynamic simulations in coral reef environments
Published: 2023-01-14
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Coral reef environments are biodiversity hotspots that provide many services to coastal communities. They are currently facing an increasing anthropogenic pressure that jeopardises their survival. Numerical ocean models are an important tool to understand the functioning of coral ecosystems and the mechanisms ensuring their resilience. However, simulating the water circulation through reef [...]
Improving Shoreline Forecasting Models with Multi-Objective Genetic Programming
Published: 2023-01-10
Subjects: Artificial Intelligence and Robotics, Climate, Environmental Engineering, Environmental Monitoring, Geomorphology, Hydrology, Numerical Analysis and Scientific Computing, Oceanography, Sedimentology, Statistical Models
Given the current context of climate change and increasing population densities at coastal zones, there is an increasing need to be able to predict the development of our coasts. Recent advances in artificial intelligence allow for automatic analysis of observational data. This work makes use of Symbolic Regression, a type of Machine Learning algorithm, to evolve interpretable shoreline [...]
Weakening of the Indian Ocean Dipole in the mid-Holocene due to the mean oceanic climatology change
Published: 2023-01-10
Subjects: Atmospheric Sciences, Climate, Meteorology, Oceanography
The Indian Ocean Dipole (IOD) is one of the leading modes of interannual climate variability in the tropical Indian Ocean (IO). Paleoclimate provides real climate scenarios to examine IOD behaviors and the linkage to basic states. Based on 18 models from the Paleoclimate Modelling Intercomparison Project phase 3 and 4 (PMIP 3/4), the IOD change from the preindustrial period to mid-Holocene is [...]
Historical & future maximum ocean temperatures
Published: 2022-12-16
Subjects: Oceanography
Marine heatwaves impact ocean ecosystems and are expected to become more frequent and intense with continued global warming. The ability of Earth system models to reproduce the statistical characteristics of extreme ocean temperatures has not yet been tested quantitatively, making the reliability of their future projections of marine heatwaves uncertain. We demonstrate that annual maxima of [...]
Extracting information from ocean color
Published: 2022-12-09
Subjects: Oceanography, Other Oceanography and Atmospheric Sciences and Meteorology
Products derived from remote sensing reflectances ($R_{rs}(\lambda)$), e.g. chlorophyll, phytoplankton carbon, euphotic depth, or particle size, are widely used in oceanography. Problematically, $R_{rs}(\lambda)$ may have fewer degrees of freedom (DoF) than measured wavebands or derived products. A global sea surface hyperspectral $R_{rs}(\lambda)$ dataset has DoF=4. MODIS-like multispectral [...]
Global climate change trends detected in indicators of ocean ecology
Published: 2022-12-07
Subjects: Oceanography
Climate change-driven trends in phytoplankton populations, as viewed by Earth-observing satellites, were thought to be masked by strong natural variability, so that >30 years of continuous data was needed to detect a climate trend. Here we show that climate change trends emerge more rapidly in ocean color (remote sensing reflectance, Rrs), as Rrs is multivariate and some wavebands have low [...]
Atmospheric carbon emissions from benthic trawling depend on water depth and ocean circulation
Published: 2022-10-28
Subjects: Biogeochemistry, Earth Sciences, Oceanography, Oceanography and Atmospheric Sciences and Meteorology
Through its vastness, resilience and biogeochemical complexity, the ocean offers humanity some of the largest potential natural pathways for removing carbon dioxide from the atmosphere while avoiding new sources of anthropogenic emissions. In proposing a network of new marine protected areas in service of global ocean conservation, Sala et al. describe a potentially large climate benefit of such [...]
Efficiently Simulating Lagrangian Particles in Large-Scale Ocean Flows – Data Structures and their Impact on Geophysical Applications
Published: 2022-10-26
Subjects: Fluid Dynamics, Numerical Analysis and Scientific Computing, Oceanography
Studying oceanography by using Lagrangian simulations has been adopted for a range of scenarios, such as the determining the fate of microplastics in the ocean, simulating the origin locations of microplankton used for palaeoceanographic reconstructions, for studying the impact of fish aggregation devices on the migration behaviour of tuna. These simulations are complex and represent a [...]
Energy and Momentum of a Density-Driven Overflow in the Samoan Passage
Published: 2022-10-22
Subjects: Oceanography
The energy and momentum balance of an abyssal overflow across a major sill in the Samoan Passage is estimated from two highly resolved towed sections, set 16 months apart, and results from a two-dimensional numerical simulation. Driven by the density anomaly drop across the sill, the flow is relatively steady. The system gains energy from divergence of horizontal pressure work O(5) kW/m and flux [...]
Trait-based modeling revealed higher microbial diversity leads to greater ecological resilience in response to an ecosystem disturbance
Published: 2022-10-15
Subjects: Biogeochemistry, Earth Sciences, Environmental Microbiology and Microbial Ecology Life Sciences, Microbiology, Oceanography, Oil, Gas, and Energy, Physical Sciences and Mathematics, Sustainability, Terrestrial and Aquatic Ecology
To quantitatively understand the ecological resilience of an ecosystem with specialized habitats, we focused on deep-sea microbial communities and simulated the response of diverse microbes in specialized habitats to a pulse ecosystem disturbance - the Deepwater Horizon Oil Spill in the Gulf of Mexico. Two microbial communities with equivalent metabolic libraries were acclimated to the presence [...]
Tsunami Early Warning from Global Navigation Satellite System Data using Convolutional Neural Networks
Published: 2022-09-29
Subjects: Earth Sciences, Geophysics and Seismology, Hydrology, Oceanography
We investigate the potential of using Global Navigation Satellite System (GNSS) observations to directly forecast full tsunami waveforms in real time. We train convolutional neural networks (CNNs) to use less than 9 minutes of GNSS data to forecast the full tsunami waveforms over 6 hours at select locations, and obtain accurate forecasts on a test dataset. Our training and test data consists of [...]
Improved estimation of phytoplankton abundance and fine-scale water quality features via simultaneous discrete and semi-continuous surveys
Published: 2022-08-06
Subjects: Biogeochemistry, Environmental Monitoring, Fresh Water Studies, Oceanography, Water Resource Management
The abundance and distribution of phytoplankton is driven by light and nutrient availability which in turn is controlled by larger-scale regional processes such as climatic variability and global teleconnections. However, such estimates are largely built on evidence gathered from coarse (on the order of kilometers), discrete grab sampling networks where the overall set of measured parameters is [...]