Ocean Observing System Research Articles

A review of the impacts of fisheries on open-ocean ecosystems

Abstract Open‐ocean fisheries expanded rapidly from the 1960s through the 1980s, when global fish catches peaked, plateaued and possibly began to decline. While catches remain at best stagnant, fishing effort globally continues to increase. The likelihood of ecosystem impacts occurring due to fishing is related to fishing effort and is thus also expected to be increasing. Despite this rapid growth, ecological research into the impacts of fisheries on open‐ocean environments has lagged behind coastal and deep-sea environments. This review addresses this knowledge gap by considering the roles fisheries play in controlling the open-ocean at three ecological scales: (i) species (population or stock); (ii) biological community; and (iii) ecosystem. We find significant evidence for top-down control at the species and community scales. While evidence of ecosystem-level impacts in the open-ocean were not explicit in the literature, we provide examples of these impacts in several marine pelagic systems and encourage further research at this ecological scale. At the species level, fishing can reduce abundance, and alter physiology and life history traits, which, in turn, affect the functional role of the species within the biological community. Fishing may also induce changes to open-ocean community trophodynamics, and reduce biodiversity and resilience in open-ocean ecosystems. Our ability to manage open-ocean ecosystems has significant implications for provisioning of ecosystem services and food security. However, we posit that the monitoring required to assure the sustainability of open-ocean ecosystems is not being undertaken, and will require coordination with the Global Ocean Observing System, industry, and academia.

Developing an essential ocean variable for the acoustic environment

The ocean science community has invested heavily in coordinating systems developed to make ocean observations. The Global Ocean Observing System (GOOS) is a research program developed to coordinate ocean observing systems. Expert panels identify requirements for the systems in terms of Essential Ocean Variables (EOVs). The absence of sound in the list of EOVs should be striking to most ocean acousticians. Sound propagates so well in the ocean that it is the best way to probe the marine environment over long distances. Marine organisms have evolved ways to use the physics of underwater sound for biosonar, to communicate, and to orient. During the industrial age, humans have developed similar tools, and sources such as commercial shipping have elevated ocean noise. A working group of the Partnership for Observation of the Global Oceans and linked to the International Quiet Ocean Experiment has developed a description of an Essential Ocean Variable for the Acoustic Environment designed to facilitate monitoring of the sound field of the oceans globally over decades, to model how human and natural sources create the sound field, and to define effects of changes in sound fields on marine life at the individual, population, and ecosystem levels.

Integrated Ocean Observing Systems as a source of scientific information for supporting oil spill response – From Gulf of Mexico to Gulf of Guinea

ABSTRACT As of 2013, the Gulf of Guinea produces about 5.5 million barrels of oil per day – more than 60% of the total daily crude oil production in sub-Saharan Africa. Potential oil spills and their impact on the environment and the economy are of concern. As was seen in the Deepwater Horizon oil spill in 2010, information from the United States Integrated Ocean Observing Systems (IOOS®) was key in the response. A robust IOOS-like system in the Gulf of Guinea could support oil spill response and enhance the existing Global Ocean Observing System for Africa (GOOS for Africa). There is great potential within the Gulf of Guinea for regional stakeholder resources to coordinate systematic metocean and coastal data, and share these data across the West, Central and Southern African countries. Through such coordinated efforts, the society benefits from the development of a “blue economy” and from improved disaster response more than from individual observations. Drawing from the examples in the Gulf of Mexico, the paper integrates the lessons from IOOS types of assets into useful response efforts for the Gulf of Guinea area. Responders, decision makers, scientists and the public all benefit from improved access to environmental information and forecasts. We include a “mock up” of how an IOOS asset would support scientific spill response in the Gulf of Guinea.

Advancing coastal ocean modelling, analysis, and prediction for the US Integrated Ocean Observing System

ABSTRACTThis paper outlines strategies that would advance coastal ocean modelling, analysis and prediction as a complement to the observing and data management activities of the coastal components of the US Integrated Ocean Observing System (IOOS®) and the Global Ocean Observing System (GOOS). The views presented are the consensus of a group of US-based researchers with a cross-section of coastal oceanography and ocean modelling expertise and community representation drawn from Regional and US Federal partners in IOOS. Priorities for research and development are suggested that would enhance the value of IOOS observations through model-based synthesis, deliver better model-based information products, and assist the design, evaluation, and operation of the observing system itself. The proposed priorities are: model coupling, data assimilation, nearshore processes, cyberinfrastructure and model skill assessment, modelling for observing system design, evaluation and operation, ensemble prediction, and fast predictors. Approaches are suggested to accomplish substantial progress in a 3–8-year timeframe. In addition, the group proposes steps to promote collaboration between research and operations groups in Regional Associations, US Federal Agencies, and the international ocean research community in general that would foster coordination on scientific and technical issues, and strengthen federal–academic partnerships benefiting IOOS stakeholders and end users.

Oceanic data assimilation study in northern Chile: use of a 3DVAR method

We report the use of a 3-dimensional variational (3DVAR) data assimilation method as part of a numerical model off northern Chile. The numerical model is part of an ocean forecasting project that aims to understand the impact of environmental variability on the distribution of biological species in the area. We assimilated data from a simulated ocean observing system to recover a known state, obtaining a significantly smaller error when compared to a numerical run with no assimilation. Our results validate the computational implementation of the code, and allow us to evaluate the impact of the choice of data in the assimilation process: the assimilation of sea surface height being particularly important. We note that the assimilation of surface data propagates properly to greater depths and reduces the error with reference to the known state. This was possible by using covariance error matrices calculated previously for the California coastal area. The implementation of the data assimilation module is relatively simple and permits its use in operational forecasting systems, and for the design and evaluation of future ocean observational systems.

Fifteen years progress of the TRITON array in the Western Pacific and Eastern Indian Oceans

The Triangle Trans‐Ocean Buoy Network (TRITON) project by the Japan Agency for Marine-Earth Science and Technology began with deployment in the western tropical Pacific Ocean in 1998 and has shifted to steady, long-term observations since 1999. After on-site inter-comparison with the Autonomous Temperature Line Acquisition System mooring system of the Tropical Atmosphere and Ocean (TAO) array by the National Oceanic and Atmospheric Administration, the TRITON array became the international TAO/TRITON array in 2000 as a key component of the Global Ocean and Climate Observing Systems. The TAO/TRITON array took over from the TAO array, which was developed during the Tropical Ocean and Global Atmosphere program (1985–1994), and replaced the western part of TAO with new additional real-time measurements of salinity and ocean currents. In 2001, two TRITON moorings were deployed in the eastern Indian Ocean for capturing the eastern pole of the Indian Ocean Dipole. From this initiative, the Indian Ocean Observing System (IndOOS) was designed, and the Indian Ocean mooring array (Research Moored Array for Africa–Asian–Australian Monsoon Analysis and Prediction) was developed as a key component of IndOOS. In this paper, 15 years of progress in the TRITON project in the western Pacific and eastern Indian Oceans is reviewed with regards to scientific outcomes, technological development, and collaborations with international and domestic partners. Future directions for sustainable observation in the Pacific and Indian Oceans are also discussed.

A Global Ocean Observing System for Measuring Sea Level Atmospheric Pressure: Effects and Impacts on Numerical Weather Prediction

Abstract Since 1994 the U.S. Global Drifter Program (GDP) and its international partners cooperating within the Data Buoy Cooperation Panel (DBCP) of the World Meteorological Organization (WMO) and the United Nations Education, Scientific and Cultural Organization (UNESCO) have been deploying drifters equipped with barometers primarily in the extratropical regions of the world’s oceans in support of operational weather forecasting. To date, the impact of the drifter data isolated from other sources has never been studied. This essay quantifies and discusses the effect and the impact of in situ sea level atmospheric pressure (SLP) data from the global drifter array on numerical weather prediction using observing system experiments and forecast sensitivity observation impact studies. The in situ drifter SLP observations are extremely valuable for anchoring the global surface pressure field and significantly contributing to accurate marine weather forecasts, especially in regions where no other in situ observations are available, for example, the Southern Ocean. Furthermore, the forecast sensitivity observation impact analysis indicates that the SLP drifter data are the most valuable per-observation contributor of the Global Observing System (GOS). All these results give evidence that surface pressure observations of drifting buoys are essential ingredients of the GOS and that their quantity, quality, and distribution should be preserved as much as possible in order to avoid any analysis and forecast degradations. The barometer upgrade program offered by the GDP, under which GDP-funded drifters can be equipped with partner-funded accurate air pressure sensors, is a practical example of how the DBCP collaboration is executed. Interested parties are encouraged to contact the GDP to discuss upgrade opportunities.

Atlantic waters inflow north of Svalbard: Insights from IAOOS observations and Mercator Ocean global operational system during N-ICE2015

As part of the N-ICE2015 campaign, IAOOS (Ice Atmosphere Ocean Observing System) platforms gathered intensive winter data at the entrance of Atlantic Water (AW) inflow to the Arctic Ocean north of Svalbard. These data are used to examine the performance of the 1/12° resolution Mercator Ocean global operational ice/ocean model in the marginal ice zone north of Svalbard. Modeled sea-ice extent, ocean heat fluxes, mixed layer depths, and AW mass characteristics are in good agreement with observations. Model outputs are then used to put the observations in a larger spatial and temporal context. Model outputs show that AW pathways over and around the Yermak Plateau differ in winter from summer. In winter, the large AW volume transport of the West Spitsbergen Current (WSC) (∼4 Sv) proceeds to the North East through 3 branches: the Svalbard Branch (∼0.5 Sv) along the northern shelf break of Svalbard, the Yermak Branch (∼1.1 Sv) along the western slope of the Yermak Plateau and the Yermak Pass Branch (∼2.0 Sv) through a pass in the Yermak Plateau at 80.8°N. In summer, the AW transport in the WSC is smaller (∼2 Sv) and there is no transport through the Yermak Pass. Although only eddy-permitting in the area, the model suggests an important mesoscale activity throughout the AW flow. The large differences in ice extent between winters 2015 and 2016 follow very distinct atmospheric and oceanic conditions in the preceding summer and autumn seasons. Convection-induced upward heat fluxes maintained the area free of ice in winter 2016. This article is protected by copyright. All rights reserved.

HF Radar Activity in European Coastal Seas: Next Steps toward a Pan-European HF Radar Network

High Frequency radar (HFR) is a land-based remote sensing instrument offering a unique insight to coastal ocean variability, by providing synoptic, high frequency and high resolution data at the ocean atmosphere interface. HFRs have become invaluable tools in the field of operational oceanography for measuring surface currents, waves and winds, with direct applications in different sectors and an unprecedented potential for the integrated management of the coastal zone. In Europe, the number of HFR networks has been showing a significant growth over the past ten years, with over 50 HFRs currently deployed and a number in the planning stage. There is also a growing literature concerning the use of this technology in research and operational oceanography. A big effort is made in Europe towards a coordinated development of coastal HFR technology and its products within the framework of different European and international initiatives. One recent initiative has been to make an up-to-date inventory of the existing HFR operational systems in Europe, describing the characteristics of the systems, their operational products and applications. This paper offers a comprehensive review on the present status of European HFR network, and discusses the next steps towards the integration of HFR platforms as operational components of the European Ocean Observing System, designed to align and integrate Europe’s ocean observing capacity for a truly integrated end-to-end observing system for the European coasts.

Dake Chen: unraveling the secrets of ocean–climate interaction

Abstract The ocean is a complex and mysterious system that attracts scientists around the world to unravel its secrets. Dake Chen, a distinguished physical oceanographer and an academician of the Chinese Academy of Sciences, is one of them. Since the mid-1980s, he has been studying ocean dynamics and ocean–atmosphere interaction, and has made seminal contributions to the understanding and prediction of short-term climate variability, especially the El Niño phenomenon. In a recent interview with NSR, Professor Dake Chen says that China has made significant progress in recent years in ocean research, but, in order to make breakthroughs in the field of oceanography, China needs to further expand the scope of research programs from coastal seas to open oceans, to greatly increase the investment in global ocean-observing systems and to pay more attention to fundamental scientific problems in addition to practical applications. He also calls for a better-defined national strategic plan for ocean science and technology.

El Niño, La Niña, and the global sea level budget

Abstract. Previous studies show that nonseasonal variations in global-mean sea level (GMSL) are significantly correlated with El Niño–Southern Oscillation (ENSO). However, it has remained unclear to what extent these ENSO-related GMSL fluctuations correspond to steric (i.e., density) or barystatic (mass) effects. Here we diagnose the GMSL budget for ENSO events observationally using data from profiling floats, satellite gravimetry, and radar altimetry during 2005–2015. Steric and barystatic effects make comparable contributions to the GMSL budget during ENSO, in contrast to previous interpretations based largely on hydrological models, which emphasize the barystatic component. The steric contributions reflect changes in global ocean heat content, centered on the Pacific. Distributions of ocean heat storage in the Pacific arise from a mix of diabatic and adiabatic effects. Results have implications for understanding the surface warming slowdown and demonstrate the usefulness of the Global Ocean Observing System for constraining Earth's hydrological cycle and radiation imbalance.

Observations of open-ocean deep convection in the northwestern Mediterranean Sea: Seasonal and interannual variability of mixing and deep water masses for the 2007-2013 Period

We present here a unique oceanographic and meteorological data set focus on the deep convection processes. Our results are essentially based on in situ data (mooring, research vessel, glider, and profiling float) collected from a multiplatform and integrated monitoring system (MOOSE: Mediterranean Ocean Observing System on Environment), which monitored continuously the northwestern Mediterranean Sea since 2007, and in particular high-frequency potential temperature, salinity, and current measurements from the mooring LION located within the convection region. From 2009 to 2013, the mixed layer depth reaches the seabed, at a depth of 2330m, in February. Then, the violent vertical mixing of the whole water column lasts between 9 and 12 days setting up the characteristics of the newly formed deep water. Each deep convection winter formed a new warmer and saltier “vintage” of deep water. These sudden inputs of salt and heat in the deep ocean are responsible for trends in salinity (3.3 ± 0.2 × 10−3/yr) and potential temperature (3.2 ± 0.5 × 10−3 C/yr) observed from 2009 to 2013 for the 600–2300 m layer. For the first time, the overlapping of the three “phases” of deep convection can be observed, with secondary vertical mixing events (2–4 days) after the beginning of the restratification phase, and the restratification/spreading phase still active at the beginning of the following deep convection event.

Dynamic Reusable Workflows for Ocean Science

Digital catalogs of ocean data have been available for decades, but advances in standardized services and software for catalog searches and data access now make it possible to create catalog-driven workflows that automate—end-to-end—data search, analysis, and visualization of data from multiple distributed sources. Further, these workflows may be shared, reused, and adapted with ease. Here we describe a workflow developed within the US Integrated Ocean Observing System (IOOS) which automates the skill assessment of water temperature forecasts from multiple ocean forecast models, allowing improved forecast products to be delivered for an open water swim event. A series of Jupyter Notebooks are used to capture and document the end-to-end workflow using a collection of Python tools that facilitate working with standardized catalog and data services. The workflow first searches a catalog of metadata using the Open Geospatial Consortium (OGC) Catalog Service for the Web (CSW), then accesses data service endpoints found in the metadata records using the OGC Sensor Observation Service (SOS) for in situ sensor data and OPeNDAP services for remotely-sensed and model data. Skill metrics are computed and time series comparisons of forecast model and observed data are displayed interactively, leveraging the capabilities of modern web browsers. The resulting workflow not only solves a challenging specific problem, but highlights the benefits of dynamic, reusable workflows in general. These workflows adapt as new data enter the data system, facilitate reproducible science, provide templates from which new scientific workflows can be developed, and encourage data providers to use standardized services. As applied to the ocean swim event, the workflow exposed problems with two of the ocean forecast products which led to improved regional forecasts once errors were corrected. While the example is specific, the approach is general, and we hope to see increased use of dynamic notebooks across geoscience domains.

Winter ocean‐ice interactions under thin sea ice observed by IAOOS platforms during N‐ICE2015: Salty surface mixed layer and active basal melt

AbstractIAOOS (Ice Atmosphere Arctic Ocean Observing System) platforms, measuring physical parameters at the atmosphere‐snow‐ice‐ocean interface deployed as part of the N‐ICE2015 campaign, provide new insights on winter conditions North of Svalbard. The three regions crossed during the drifts, the Nansen Basin, the Sofia Deep, and the Svalbard northern continental slope featured distinct hydrographic properties and ice‐ocean exchanges. In the Nansen Basin, the quiescent warm layer was capped by a stepped halocline (60 and 110 m) and a deep thermocline (110 m). Ice was forming and the winter mixed layer salinity was larger by ∼0.1 g/kg than previously observed. Over the Svalbard continental slope, the Atlantic Water (AW) was very shallow (20 m from the surface) and extended offshore from the 500 m isobath by a distance of about 70 km, sank along the slope (40 m from the surface) and probably shed eddies into the Sofia Deep. In the Sofia Deep, relatively warm waters of Atlantic origin extended from 90 m downward. Resulting from different pathways, these waters had a wide range of hydrographic characteristics. Sea‐ice melt was widespread over the Svalbard continental slope and ocean‐to‐ice heat fluxes reached values of 400 W m−2 (mean of ∼150 W m−2 over the continental slope). Sea‐ice melt events were associated with near 12 h fluctuations in the mixed‐layer temperature and salinity corresponding to the periodicity of tides and near‐inertial waves potentially generated by winter storms, large barotropic tides over steep topography, and/or geostrophic adjustments.

Guest Editorial Sensor Systems for a Changing Ocean

The papers in this special section focus on sensor system deployment in the field of oceanography. Oceans regulate the Earth's climate and are integral to all known sources of life. Ocean processes are of biological, geological, chemical, or physical nature, occurring at micro- to kilometer scales, from less than seconds to centuries, turning the understanding and the sustainable management of the ocean into a multiscale and multidisciplinary effort. Collection of in situ observation of a volume that covers over 70% of the planet is also inherently challenging and remains generally difficult and costly in time and resources, with so far a rather unsatisfactory result, in particular with respect to space-time resolution. Over the past decade, there has been a steady crescendo of interest to support the development of a truly integrated and sustainably funded Ocean Observing System. This will be achieved with more long-term measurements of key parameters but is impaired by the costs and lack of reliability of ocean sensors in general.

Initial skill assessment of the California Harmful Algae Risk Mapping (C-HARM) system

Toxic algal events are an annual burden on aquaculture and coastal ecosystems of California. The threat of domoic acid (DA) toxicity to human and wildlife health is the dominant harmful algal bloom (HAB) concern for the region, leading to a strong focus on prediction and mitigation of these blooms and their toxic effects. This paper describes the initial development of the California Harmful Algae Risk Mapping (C-HARM) system that predicts the spatial likelihood of blooms and dangerous levels of DA using a unique blend of numerical models, ecological forecast models of the target group, Pseudo-nitzschia, and satellite ocean color imagery. Data interpolating empirical orthogonal functions (DINEOF) are applied to ocean color imagery to fill in missing data and then used in a multivariate mode with other modeled variables to forecast biogeochemical parameters. Daily predictions (nowcast and forecast maps) are run routinely at the Central and Northern California Ocean Observing System (CeNCOOS) and posted on its public website. Skill assessment of model output for the nowcast data is restricted to nearshore pixels that overlap with routine pier monitoring of HABs in California from 2014 to 2015. Model lead times are best correlated with DA measured with solid phase adsorption toxin tracking (SPATT) and marine mammal strandings from DA toxicosis, suggesting long-term benefits of the HAB predictions to decision-making. Over the next three years, the C-HARM application system will be incorporated into the NOAA operational HAB forecasting system and HAB Bulletin.

A sea of potential: The politics of global ocean observations

The Global Ocean Observing System (GOOS) is creating a new understanding of the world ocean. With a vast and heterogeneous network of sensors, it converts the ocean's properties into flows of information, creating a “data double” of a dynamic sea. This view of the ocean underlies not only international geopolitics but also more broadly emergent modes of government. This paper analyzes changing strategies for governing global ocean observations to better understand the shifting coconstitution of nature, technology, and politics. In particular, I inquire into the GOOS's recent developments, which indicate a new conception of the ocean as a space of potentiality. I argue that this emergent understanding poses problems for our conventional political analytics, particularly that of biopolitics. To account for this shift, I draw on and extend Elizabeth Povinelli's offering of geontopolitics, which identifies a departure from the fundamental distinctions between life and nonlife made by biopolitics, seeing instead the potential for unpredictable changes not only in human subjects but also in geophysical systems and the contemporary planetary environmental conditions they shape. Emphasizing how geontopolitics both names a new mode of government and signifes its limits, Povinelli suggests three figures, following Foucault's four figures of biopolitics. I conclude by suggesting the world ocean as a fourth figure of geonotopolitics, as that which is so imbricated with life as to be indistinct from it. Throughout, I maintain that like Foucault's figures of biopolitics, the world ocean must be understood as inseparable from the knowledge relations that make it legible.

Ocean Observing: Serving Stakeholders in the Pacific Islands

AbstractOperating an ocean observing system in a region as vast and diverse as the Exclusive Economic Zone of the U.S. Pacific Islands poses common and unique challenges that require tailored solutions. In order to address stakeholder needs for ocean data and information in a cost-effective and impactful manner, the Pacific Islands Ocean Observing System (PacIOOS) functions under a framework of stakeholder-driven priority setting. This strategy employs an innovative categorization of stakeholders into four general categories for the purpose of delineating levels of engagement: (a) data super users, (b) industry and natural resource managers, (c) informed public ocean users, and (d) the general public. Stakeholder needs are continuously gathered through many avenues, including staff dedicated to communications and engagement throughout the region and a higher-level governance framework composed of signatory partners. Principles of degree of need and potential for positive impact are utilized for prioritization. Although PacIOOS cannot engage with all stakeholders in the region, the approach taken to identify, engage, and respond to stakeholders serves as an effective and efficient method to ensure that both specific ocean stakeholders and stakeholders, writ large, benefit from the resources and efforts expended to advance ocean observing in the region. Two case studies from separate geographies and components of the PacIOOS program illustrate the value of this stakeholder-driven approach to users in the region. This approach may serve as a model for how to effectively address stakeholder needs and improve decision making through a regional ocean observing system.

India's Ocean Observation Network: Relevance to Society

AbstractSustained and real-time ocean observation systems using moored data buoys are vital for understanding ocean dynamics and the variability required for improving oceanographic services, including weather prediction, ocean state forecast, and climate change studies. This paper presents the effectiveness of India's moored data buoy network in capturing the response in the ocean during the cyclonic disturbances formed in the Bay of Bengal (BoB) and the Arabian Sea (AS) during the last 5-year period. The moored buoy network provided critical information about the evolution and intensification of low-pressure systems and supported the India Meteorological Department to improve prediction capabilities by incorporating real-time data. The lowest mean sea-level pressure of 920 hPa was recorded in the BoB during the very severe cyclonic storm Phailin. The warning systems adopted for the effective dissemination of the ocean forecast services to the user community have significantly reduced the loss of life and property in coastal states.

Optimizing observational networks combining gliders, moored buoys and FerryBox in the Bay of Biscay and English Channel

Designing optimal observation networks in coastal oceans remains one of the major challenges towards the implementation of future efficient Integrated Ocean Observing Systems to monitor the coastal environment. In the Bay of Biscay and the English Channel, the diversity of involved processes (e.g. tidally-driven circulation, plume dynamics) requires to adapt observing systems to the specific targeted environments. Also important is the requirement for those systems to sustain coastal applications.Two observational network design experiments have been implemented for the spring season in two regions: the Loire River plume (northern part of the Bay of Biscay) and the Western English Channel. The method used to perform these experiments is based on the ArM (Array Modes) formalism using an ensemble-based approach without data assimilation.The first experiment in the Loire River plume aims to explore different possible glider endurance lines combined with a fixed mooring to monitor temperature and salinity. Main results show an expected improvement when combining glider and mooring observations. The experiment also highlights that the chosen transect (along-shore and North–South, cross-shore) does not significantly impact the efficiency of the network. Nevertheless, the classification from the method results in slightly better performances for along-shore and North–South sections.In the Western English Channel, a tidally-driven circulation system, added value of using a glider below FerryBox temperature and salinity measurements has been assessed. FerryBox systems are characterised by a high frequency sampling rate crossing the region 2 to 3 times a day. This efficient sampling, as well as the specific vertical hydrological structure (which is homogeneous in many sub-regions of the domain), explains the fact that the added value of an associated glider transect is not significant.These experiments combining existing and future observing systems, as well as numerical ensemble simulations, highlight the key issue of monitoring the whole water column in and close to river plumes (using gliders for example) and the efficiency of the surface high frequency sampling from FerryBoxes in macrotidal regions.