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Ocean Dynamics, Gregg Jacobs, Baylor Fox-Kemper

Journal of Marine Research

Operational prediction systems must balance conflicting considerations involved in representing the widest possible range of ocean physics, limited by computational constraints. Choices must be made in prediction systems that exclude particular dynamics to enable feasible solutions within defined resources. We examine some of the basic ocean dynamics that ocean prediction systems intend to represent. The two most basic simplifications are the Boussinesq and hydrostatic. Even with these limitations, ocean models represent a vast range of physical processes, and this enables application to many problems. We examine a succinct range of basic dynamics and consider how these affect operational ocean prediction …

Observations Of The East Madagascar Current System: Dynamics And Volume Transports, Aksel Voldsund, Borja Aguiar-González, Tor Gammelsrød, Jens-Otto Krakstad, Jenny Ullgren

Journal of Marine Research

The South Equatorial Current (SEC) in the Indian Ocean bifurcates when it reaches Madagascar leading, respectively, to the North East Madagascar Current (NEMC), which contours the island flowing northwestward, and to the South East Madagascar Current (SEMC), which flows southwestward. Both branches eventually contribute to the greater Agulhas Current system and thus play a part in the global ocean circulation. In addition, these currents have important effects on the local conditions for marine life. In this study, the NEMC and the SEMC are investigated based on a comprehensive, multidisciplinary survey of the east coast of Madagascar in 2008. Results from …

Reconstructing The Recent Past Ocean Variability: Status And Perspective, Simona Masina, Andrea Storto

Journal of Marine Research

In the last two decades, climate research has benefited from the continuous development of analysis systems dedicated to operational monitoring and forecasting, which opened up the possibility of exploiting the state of the art modeling and data assimilation tools to reconstruct and study the ocean during the past decades. This activity became feasible also thanks to the increasing availability of long time series of high-quality in situ and remotely-sensed observations. Retrospective analyses (or simply reanalyses or ocean syntheses), indeed combine quality controlled reprocessed ocean observations with a state-of-the-art ocean general circulation model (OGCM) using data assimilation methods to estimate the …

The North Icelandic Jet And Its Relationship To The North Icelandic Irminger Current, Robert S. Pickart, Michael A. Spall, Daniel J. Torres, Kjetil Våge, Hedinn Valdimarsson, C. Nobre, G. W. K. Moore, Steingrimur Jonsson, Dana Mastropole

Journal of Marine Research

Shipboard hydrographic and velocity sections are used to quantify aspects of the North Icelandic Jet (NIJ), which transports dense overflow water to Denmark Strait, and the North Icelandic Irminger Current (NIIC), which imports Atlantic water to the Iceland Sea. The mean transports of the two currents are comparable, in line with previous notions that there is a local overturning cell in the Iceland Sea that transforms the Atlantic water to dense overflow water. As the NIJ and NIIC flow along the north side of Iceland, they appear to share a common front when the bottom topography steers them close together, …

A Future For Intelligent Autonomous Ocean Observing Systems, P. F.J. Lermusiaux, D. N. Subramani, J. Lin, C. S. Kulkarni, A. Gupta, A. Dutt, T. Lolla, P. J. Haley Jr., W. H. Ali, C. Mirabito, S. Jana

Journal of Marine Research

Ocean scientists have dreamed of and recently started to realize an ocean observing revolution with autonomous observing platforms and sensors. Critical questions to be answered by such autonomous systems are where, when, and what to sample for optimal information, and how to optimally reach the sampling locations. Definitions, concepts, and progress towards answering these questions using quantitative predictions and fundamental principles are presented. Results in reachability and path planning, adaptive sampling, machine learning, and teaming machines with scientists are overviewed. The integrated use of differential equations and theory from varied disciplines is emphasized. The results provide an inference engine and …

Oil Spill Forecasting (Prediction), George Zodiatis, Robin Lardner, Tiago M. Alves, Yiannis Krestenitis, Leonidas Perivoliotis, Sarantis Sofianos, Katerina Spanoudaki

Journal of Marine Research

Oil spills in the ocean are a matter of concern due to the damaging effect they can have on coastal and offshore resources. This work presents a review of present-day modeling techniques used in the mitigation of oil spills by booms, skimmers, chemical dispersants, and other equipment and the importance of the controlling parameters of these techniques. Three basic questions need to be addressed by oil spill models: (1) where the spill will move, (2) when will the spill get to the modeled endpoints, and (3) what will be its state when it arrives. The first two questions are relatively …

Coupled Ocean-Atmosphere Forecasting At Short And Medium Time Scales, Julie Pullen, Richard Allard, Hyodae Seo, Arthur J. Miller, Shuyi Chen, Luciano Ponzi Pezzi, Travis Smith, Philip Chu, José Alves, Rui Caldeira

Journal of Marine Research

Recent technological advances over the past few decades have enabled the development of fully coupled atmosphere-ocean modeling prediction systems that are used today to support short-term (days to weeks) and medium-term (10–21 days) needs for both the operational and research communities. We overview the coupling framework, including model components and grid resolution considerations, as well as the coupling physics by examining heat fluxes between atmosphere and ocean, momentum transfer, and freshwater fluxes. These modeling systems can be run as fully coupled atmosphere-ocean and atmosphere-ocean-wave configurations. Examples of several modeling systems applied to complex coastal regions including Madeira Island, Adriatic Sea, …

The Generation Of Rossby Waves And Wake Eddies By Small Islands, R. C. Musgrave, G. Flierl, T. Peacock

Journal of Marine Research

The influence of small islands on zonal geostrophic currents is examined in a two-layer configuration. An analytic solution for steady quasigeostrophic flow is derived under the assumption of no upstream influence and is validated numerically in a time-dependent quasigeostrophic model. Under these conditions solutions are the sum of two eigenmodes, which are either arrested Rossby waves or evanescent depending on background flow conditions (layer speeds, stratification, and latitude). In contrast to homogeneous flows, arrested Rossby waves in two layers can occur even when the depth mean flow is westward and can be generated both to the east and west of …

Distribution Of Selenium In The Plume Of The Gediz River, Izmir Bay, Aegean Sea, Nihayet Bizsel, Murat V. Ardelan, Kemal C. Bizsel, Ayşin Suzal, Aylin Demirdaǧ, Deniz Y. Sarica, Eiliv Steinnes

Journal of Marine Research

Selenium (Se) variations in the water column, suspended particulate matter, and sediment through the salinity gradient, together with water-quality parameters, were investigated over four different river conditions: lowest–highest runoff and high–low production period between November 2004 and August 2005 in the plume of the Gediz River, Aegean Sea, Turkey. The drainage basin of the Gediz delta is predominantly agricultural and industrial in character. Dissolved Se exceeded the water-quality standard of 5 μg L^–1 during high flow and varied from 9.4 μg L^–1 to 0.02 μg L^–1 through the salinity gradient during the study period. Particulate Se ranged …

From Weather To Ocean Predictions: An Historical Viewpoint, Nadia Pinardi, L. Cavaleri, G. Coppini, P. De Mey, C. Fratianni, J. Huthnance, P. F. J. Lermusiaux, A. Navarra, R. Preller, S. Tibaldi

Journal of Marine Research

This paper reviews the historical development of concepts and practices in the science of ocean predictions. It begins with meteorology, which conducted the first forecasting experiment in 1950, followed by wind waves, and continuing with tidal and storm surge predictions to arrive at the first successful ocean mesoscale forecast in 1983. The work of Professor A. R. Robinson of Harvard University, who produced the first mesoscale ocean predictions for the deep ocean regions is documented for the first time. The scientific and technological developments that made accurate ocean predictions possible are linked with the gradual understanding of the importance of …

Modeling And Forecasting The “Weather Of The Ocean” At The Mesoscale, Anne Marie Treguier, Eric P. Chassignet, Arnaud Le Boyer, Nadia Pinardi

Journal of Marine Research

We present a historical perspective on ocean mesoscale variability and turbulence, from the physical basis and the first numerical models to recent simulations and forecasts. In the mesoscale range (typically, spatial scales of 100 km and time scales of a month), nonlinearity, and energy cascades were well understood in the 1970s, but the emergence of coherent vortices took place much later. New challenges have arisen with the exploration of the submesoscale regime, where frontal dynamics play a key role and the range of flow instabilities is wider than in the quasi-geostrophic regime. Special focus is placed on the interaction of …

Ocean Forecasting For Wave Energy Production, Alexis Mérigaud, Victor Ramos, Francesco Paparella, John V. Ringwood

Journal of Marine Research

There are a variety of requirements for future forecasts in relation to optimizing the production of wave energy. Daily forecasts are required to plan maintenance activities and allow power producers to accurately bid on wholesale energy markets, hourly forecasts are needed to warn of impending inclement conditions, possibly placing devices in survival mode, while wave-by-wave forecasts are required to optimize the real-time loading of the device so that maximum power is extracted from the waves over all sea conditions. In addition, related hindcasts over a long time scale may be performed to assess the power production capability of a specific …

Coupled Ocean–Atmosphere Modeling And Predictions, Arthur J. Miller, Mat Collins, Silvio Gualdi, Tommy G. Jensen, Vasu Misra, Luciano Ponzi Pezzi, David W. Pierce, Dian Putrasahan, Hyodae Seo, Yu-Heng Tseng

Journal of Marine Research

Key aspects of the current state of the ability of global and regional climate models to represent dynamical processes and precipitation variations are summarized. Interannual, decadal, and global-warming timescales, wherein the influence of the oceans is relevant and the potential for predictability is highest, are emphasized. Oceanic influences on climate occur throughout the ocean and extend over land to affect many types of climate variations, including monsoons, the El Niño Southern Oscillation, decadal oscillations, and the response to greenhouse gas emissions. The fundamental ideas of coupling between the ocean-atmosphere-land system are explained for these modes in both global and regional …

Issues In Stochastic Ocean Modeling, Cecile Penland, Antonio Navarra

Journal of Marine Research

The general theory of stochastic differential equations is presented in this chapter, including the theoretical background on how measured statistics from time series can be used to develop a stochastic parameterization. The general rules of stochastic calculus, including the important and often overlooked differences between Ito and Stratonovich calculus, are mentioned, and references are provided in which more detail may be found. We discuss how Stratonovich calculus is usually appropriate for fluid systems, whereas Ito calculus is often appropriate for data assimilation. We also discuss some common numerical pitfalls awaiting the unwary modeler, and warn against unsophisticated random number generators. …

Advanced Wave Modeling, Including Wave-Current Interaction, Alexander V. Babanin, Andre Van Der Weshuijsen, Dmitry Chalikov, W. Erick Rogers

Journal of Marine Research

The paper outlines principles of phase-resolving and phase-average wave models, with emphasis on the state of the art of wave-current interaction physics. We argue that these interactions are the least well-developed part of such models. Linear and nonlinear dynamics of waves on currents are discussed; depth-integrated and depth-varying approaches are described. Finally, examples of numerical model performance for waves on currents in realistic oceanic scenarios are presented.

Tidal Prediction, Gary D. Egbert, Richard D. Ray

Journal of Marine Research

Tides are the most predictable of oceanographic phenomena, due both to the simplicity and predictability of the astronomical forcing and to the near linearity of the ocean's dynamical response. In the classical and simplest scenario, tidal prediction is based on harmonic analysis of past measurements at a fixed location. Limits to predictability arise because isolated astronomical spectral lines are broadened into "cusps" of incoherent energy, for example through interactions with non-tidal flows. Tidal prediction at locations without past measurements has historically been a major challenge, but, owing to near-global observations of modern satellite altimeters, the empirical harmonic approach now yields …

Modeling And Forecasting Ocean Acoustic Conditions, Timothy F. Duda

Journal of Marine Research

Modeling acoustic conditions in an oceanic environment is a multiple-step process. The environmental conditions (features) in the area first must be measured or estimated; relevant features include seabed geometry, seabed composition, and four-dimensionally (4D) variable sound-speed and density variations related to evolving or wave motions. Often the dynamical wave modeling depends on first obtaining correct seabed and mean stratification conditions (for example, nonlinear internal wave modeling). Next, this information must be included in sound propagation modeling. A selection of the many methods and tools available for these tasks are described, with a focus on modeling sounds of 20 to 1000 …

Aabw-Transport Variation And Its Effect On Internal Wave Motions Between Top And Bottom Of The Puerto Rico Trench, Hans Van Haren

Journal of Marine Research

Slow subinertial variations in Antarctic Bottom Water (AABW) are investigated interacting with internal waves and associated turbulent mixing in the Puerto Rico Trench (PRT), northwest Atlantic. Just below the PRT's top at 5,500 m, a deep-sea mooring was deployed for 14 months. Around 6,100 m, the line held a 200 m long string of 101 high-resolution temperature sensors and a current meter. Around 8,250 m, a similar string held 102 sensors, of which the lowest was 9 m above the bottom. As was measured with shipborne conductivity-temperature-depth profiling down to 7,150 m, PRT waters are very weakly stratified, with local …

Measurement And Modeling Of Volume Scattering Functions For Phytoplankton From Norwegian Coastal Waters, Endre Marken, Nicolausi Ssebiyonga, Jon K. Lotsberg, Jakob J. Stamnes, Børge Hamre, Øyvind Frette, Arne Skodvin Kristoffersen, Svein Rune Erga

Journal of Marine Research

The volume scattering function (VSF) describes the angular distribution of scattered light, and the VSF of phytoplankton is one of the most important inherent optical properties of oceanic water. Despite its importance, relatively few measurements of the VSF have been carried out in aquatic environments, and we present here data and analyses of measured VSFs at 442, 490, and 550 nm for 15 representative phytoplankton species from Norwegian coastal waters. In addition, the analytic scattering phase functions Henyey-Greenstein (HG) and Fournier-Forand, as well as Mie theory, were fitted and compared to the measured VSFs. The measured VSFs for all the …

Numerical Modelling In A Multiscale Ocean, Dale B. Haidvogel, Enrique N. Curchitser, Sergey Danilov, Baylor Fox-Kemper

Journal of Marine Research

Systematic improvement in ocean modelling and prediction systems over the past several decades has resulted from several concurrent factors. The first of these has been a sustained increase in computational power, as summarized in Moore's Law, without which much of this recent progress would not have been possible. Despite the limits imposed by existing computer hardware, however, significant accruals in system performance over the years have been achieved through novel innovations in system software, specifically the equations used to represent the temporal evolution of the oceanic state as well as the numerical solution procedures employed to solve them. …

Coupled Ice-Ocean Modeling And Predictions, Laurent Bertino, Marika M. Holland

Journal of Marine Research

We review the coupled ice-ocean modeling activities aimed at predictions, both in the near term (days to a week) and in the long term (seasonal to decadal) of the polar oceans. First the state of the knowledge of potential predictability is exposed, then an overview is given of the tools available for carrying out such predictions: the observations that can be used to initialize actual predictions, the coupled ice-ocean–modeling, including the fully-coupled Earth System Models for long-term predictions, and data-assimilation techniques. Finally, the performance of existing prediction systems is reviewed, showing that, although more predictive capability remains than what is …

Seasonal Fish And Invertebrate Communities In Three Northern California Estuaries, Katherine Osborn

Cal Poly Humboldt theses and projects

The majority of Northern California estuaries are small, flooded, river valleys that are largely unstudied due to their small sizes and remote locations. Yet these estuaries serve as important nursery areas for many marine fish species including rockfish, flatfish, smelt, and herring, and they are vital to anadromous species such as Chinook Salmon (Oncorhynchus tshawytscha) and Steelhead (O. mykiss). I sampled the summer and winter fish and invertebrate communities of the Big, Mad, and Ten Mile river estuaries. Fish were sampled via beach seine or fyke net and invertebrates were sampled via benthic cores, June 2014-June …

Twenty-First Century Climate Change And Submerged Aquatic Vegetation In A Temperate Estuary: The Case Of Chesapeake Bay, Thomas M. Arnold, Richard C. Zimmerman, Katharina A.M. Engelhardt, J. Court Stevenson

OES Faculty Publications

Introduction: The Chesapeake Bay was once renowned for expansive meadows of submerged aquatic vegetation (SAV). However, only 10% of the original meadows survive. Future restoration effortswill be complicated by accelerating climate change, including physiological stressors such as a predicted mean temperature increase of 2-6°C and a 50-160% increase in CO2 concentrations.

Outcomes: As the Chesapeake Bay begins to exhibit characteristics of a subtropical estuary, summer heat waves will become more frequent and severe. Warming alone would eventually eliminate eelgrass (Zostera marina) from the region. It will favor native heat-tolerant species such as widgeon grass (Ruppia maritima) while facilitating colonization by …

Data Assimilation For Initialization Of Seasonal Forecasts, Magdalena A. Balmaseda

Journal of Marine Research

This article reviews the requirements for a data assimilation system from the perspective of initializing seasonal forecasts. It provides a historical perspective of the developments in ocean data assimilation and ocean observing systems. It also discusses the differences between state estimation and initialization, and presents a brief assessment of different initialization strategies. The value of assimilating ocean data to estimate the ocean state and to initialize seasonal forecasts is demonstrated. However, it is also shown that the assumption of unbiased models in conventional data assimilation methods is not suitable for the production of long temporal records of ocean initial states. …

Ocean Acidification Accelerates The Growth Of Two Bloom-Forming Macroalgae, Craig S. Young, Christopher J. Gobler

School of Marine & Atmospheric Sciences Faculty Publications

While there is growing interest in understanding how marine life will respond to future ocean acidification, many coastal ecosystems currently experience intense acidification in response to upwelling, eutrophication, or riverine discharge. Such acidification can be inhibitory to calcifying animals, but less is known regarding how non-calcifying macroalgae may respond to elevated CO2. Here, we report on experiments performed during summer through fall with North Atlantic populations of Gracilaria and Ulva that were grown in situ within a mesotrophic estuary (Shinnecock Bay, NY, USA) or exposed to normal and elevated, but environmentally realistic, levels of pCO2 and/or nutrients (nitrogen and phosphorus). …

A New Multispectral Imaging Instrument For In-Situ Characterization Of Flocs And Colloidal Aggregates In Natural Waters, Charles R. Bostater

Ocean Engineering and Marine Sciences Faculty Publications

No abstract provided.

A Literature Review Of The Beneficial Use Of Dredged Material And Sediment Management Plans And Strategies, Portland State University. Hatfield School Of Government. Center For Public Service, Michelle Welch, Eric Thomas Mogren, Lauren Beeney

Center for Public Service Publications and Reports

This report identifies lessons learned from the body of existing literature on dredge sediment beneficial uses. It also examines the constructive role collaborative processes can play in development of sediment management plans. The authors reviewed approximately 100 documents and reports for this project. Seventeen of those were reviewed in detail based on their relevance in identifying sediment beneficial uses and/or the use of collaborative processes in the development of sediment management plans. A number of these documents were sediment management plans and strategies for specific projects and programs in other locations. The report presents findings and lessons for the consideration …

Western North Pacific Integrated Physical-Biogeochemical Ocean Observation Experiment (Inbox): Part 1.Specifications And Chronology Of The S1-Inbox Floats, Ryuichiro Inoue, Toshio Suga, Shinya Kouketsu, Toshiyuki Kita, Shigeki Hosoda, Taiyo Kobayashi, Kanako Sato, Hiroyuki Nakajima, Takeshi Kawano

Journal of Marine Research

An interdisciplinary project called the Western North Pacific Integrated Physical-Biogeochemical Ocean Observation Experiment (INBOX) has been conducted since 2011. In the oligotrophic subtropics south of the Kuroshio Extension near biogeochemical mooring S1 (30° N, 145° E), 18 floats, each with a dissolved oxygen sensor, have been deployed in a 150 × 150 km square area. With the horizontal (30 km) and temporal (2 days) resolution of the data, we observed an upper ocean structure associated with mesoscale eddies and ocean responses to atmospheric forcing. The data set obtained from the S1-INBOX study was used to elucidate the impacts of physical …

Western North Pacific Integrated Physical-Biogeochemical Ocean Observation Experiment (Inbox): Part 3. Mesoscale Variability Of Dissolved Oxygen Concentrations Observed By Multiple Floats During S1-Inbox, Shinya Kouketsu, Ryuichiro Inoue, Toshio Suga

Journal of Marine Research

As part of the interdisciplinary project S1-INBOX (Western North Pacific Integrated Physical-Biogeochemical Ocean Observation Experiment conducted around the S1 biogeochemical mooring site), we used data from more than 18 floats and a biogeochemical mooring S1 (near 30° N, 145° E) to investigate temporal and spatial changes in the shallow oxygen maximum (SOM) associated with a mesoscale cyclonic eddy. On the northern edge of the cyclonic eddy, patches (linear dimensions of 20–40 km) with relatively high oxygen concentrations were observed around the SOM. The patterns of the oxygen concentrations reflected the fact that changes of the depths of the isopycnal surfaces …

Baroclinic Instability Over Topography: Unstable At Any Wave Number, Joseph Pedlosky

Journal of Marine Research

The instability of an inviscid, baroclinic vertically sheared current of uniform potential vorticity, flowing along a uniform topographic slope, becomes linearly unstable at all wave numbers if the flow is in the direction of propagation of topographic waves. The parameter region of instability in the plane of scaled topographic slope versus wave number then extends to arbitrarily large wave numbers at large slopes. The weakly nonlinear treatment of the problem reveals the existence of a nonlinear enhancement of the instability close to one of the two boundaries of this parametrically narrow unstable region. Because the domain of instability becomes exponentially …