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The European Ocean Observing Community (EOOC) integrates inputs from diverse entities dedicated to comprehensively monitoring and forecasting oceanic phenomena in European Seas. With increasing climate and anthropogenic pressures, the urgency of ensuring the EOOC's preparedness to observe Essential Ocean Variables (EOVs) is evident. This paper advocates for the adoption of a scoring approach designed to evaluate the readiness of the EOOC in observing and forecasting key ocean phenomena. The proposed scoring methodology can be applied at both European and potentially regional and/or national levels, and emerges as a transformative tool for scrutinizing the EOOC's capability to predict and monitor key ocean phenomena. Our findings, based on the application of the scoring approach, suggest that while the community demonstrates commendable readiness levels for certain oceanic phenomena, 83% remain in developing stages, oscillating between "Idea" and "Trial" readiness levels. A closer examination exposes critical shortages predominantly in the coordination and observational facets (Process), and data management and information products (Output). The implications of these identified gaps reach far beyond academic realms, profoundly affecting diverse sectors and societal resilience (e.g., energy sector). The suggested scoring approach serves as a clear call for strategic investments and heightened support for the European observing community. By adopting a regular and systematic scoring methodology, we not only measure progress at present but also pave the way for a resilient and future-ready EOOC. [ABSTRACT FROM AUTHOR]

The EU funded project EuroSea brought together key actors of the European ocean observing and forecasting communities with key users of the ocean observing products and services in order to better integrate existing ocean observation systems and tools, and to improve the delivery of ocean information to users. EuroSea was constructed around the ocean observing value chain that connects observations to users of ocean information, and, just as intended, the value chain concept was a useful prism to improve the system. In this article, we summarize some of the main take-home messages from EuroSea on the needs for developing the European Ocean Observing System and its links with modeling and forecasting systems. During the project, the challenges and gaps in the design and coordination of the European ocean observing and forecasting system were identified and mapped. Many gaps and challenges related to the observations of physical, chemical and biological Essential Ocean Variables were identified. Some of these gaps are related to technological developments, while others are caused by insufficient and shortterm funding leading to a not sustainable system, management, and cooperation between different entities, as well as limitations in foresight activities, policies and decisions. This article represents a compilation of the broader needs for advancing the observing and forecasting system, and is meant as a guide for the community, and to funders and investors to advance ocean observing and the delivery of ocean information in Europe. To enhance the sustainability of ocean observations, which is paramount for a reliable provision of quality oceanographic data and services, several recommendations were compiled for ocean observing networks, frameworks, initiatives, as well as the ocean observing funders within the European nations, and the European Commission. [ABSTRACT FROM AUTHOR]

The interdisciplinary community of ocean and coastal observers and modelers in Europe is driven by national observing needs for prediction and management of intricate processes shaping Europe's Seas. Not all observing needs can be addressed by nations alone and various coordination activities exist to overcome fragmentation and create cross benefit within the European Ocean Observing Community (EOOC). This way critical insights into impacts of climate change on European Waters and cross border marine resources management can be achieved. Based on a large number of published material, this article is identifying and addressing the current state of activities of the EOOC and states gaps that potentially prevent efficacy. Key challenges include spatial and temporal coverage in observations, data integration, accessibility, uncertainties in projections, technological hurdles, and engagement and communication gaps. Detailed recommendations are provided for identified gaps, offering valuable insights for stakeholders, funders, and supporters of the EOOC. These recommendations, extending beyond academic interest, carry significant implications for climate change mitigation, marine resource management efficiency, ecosystem resilience, disaster preparedness, economic benefits, and the broader scientific advancements in European marine science, thereby benefiting society at large. As the world undergoes transformative changes impacting all facets of European life, substantial investment and support for the EOOC are crucial for precise information, accurate predictions, supporting sustained services that contribute to business growth and community resilience, and a sustainable ocean. [ABSTRACT FROM AUTHOR]

The European Ocean Observing Community (EOOC) integrates inputs from diverse entities dedicated to comprehensively monitoring and forecasting oceanic phenomena in European Seas. With increasing climate and anthropogenic pressures, the urgency of ensuring the EOOC’s preparedness to observe Essential Ocean Variables (EOVs) is evident. This paper advocates for the adoption of a scoring approach designed to evaluate the readiness of the EOOC in observing and forecasting key ocean phenomena. The proposed scoring methodology can be applied at both European and potentially regional and/or national levels, and emerges as a transformative tool for scrutinizing the EOOC’s capability to predict and monitor key ocean phenomena. Our findings, based on the application of the scoring approach, suggest that while the community demonstrates commendable readiness levels for certain oceanic phenomena, 83% remain in developing stages, oscillating between “Idea” and “Trial” readiness levels. A closer examination exposes critical shortages predominantly in the coordination and observational facets (Process), and data management and information products (Output). The implications of these identified gaps reach far beyond academic realms, profoundly affecting diverse sectors and societal resilience (e.g., energy sector). The suggested scoring approach serves as a clear call for strategic investments and heightened support for the European observing community. By adopting a regular and systematic scoring methodology, we not only measure progress at present but also pave the way for a resilient and future-ready EOOC.

Polar systems are experiencing major changes that has significant implications for ocean circulation and global biogeochemistry. While these changes are accelerating, access to polar systems is decreasing as ships and logistical capabilities are declining. Autonomous underwater buoyancy gliders have proven to be robust technologies that are capable of filling sampling gaps. Gliders have also provided a more sustained presence in polar seas than ships are able. Along the West Antarctic Peninsula, one of the most rapidly warming regions on this planet, gliders have proven to be a useful tool being used by the international community to link land research stations without requiring major research vessel ship support. The gliders are capable of adaptive sampling of subsurface features not visible from satellites, sustained sampling to characterize seasonal dynamics, and they increasingly play a central role in themanagement of natural resources. Future challenges to expand their utility include: (A) developing robust navigation under ice, which would allow gliders to provide a sustained bridge between the research stations when ship support is declining, and (B) expanding online resources to provide the international community open access to quality data in near real time. These advances will accelerate the use of gliders to fill critical sampling gaps for these remote ocean environments. [ABSTRACT FROM AUTHOR]

The EU funded project EuroSea brought together key actors of the European ocean observing and forecasting communities with key users of the ocean observing products and services in order to better integrate existing ocean observation systems and tools, and to improve the delivery of ocean information to users. EuroSea was constructed around the ocean observing value chain that connects observations to users of ocean information, and, just as intended, the value chain concept was a useful prism to improve the system. In this article, we summarize some of the main take-home messages from EuroSea on the needs for developing the European Ocean Observing System and its links with modeling and forecasting systems. During the project, the challenges and gaps in the design and coordination of the European ocean observing and forecasting system were identified and mapped. Many gaps and challenges related to the observations of physical, chemical and biological Essential Ocean Variables were identified. Some of these gaps are related to technological developments, while others are caused by insufficient and short-term funding leading to a not sustainable system, management, and cooperation between different entities, as well as limitations in foresight activities, policies and decisions. This article represents a compilation of the broader needs for advancing the observing and forecasting system, and is meant as a guide for the community, and to funders and investors to advance ocean observing and the delivery of ocean information in Europe. To enhance the sustainability of ocean observations, which is paramount for a reliable provision of quality oceanographic data and services, several recommendations were compiled for ocean observing networks, frameworks, initiatives, as well as the ocean observing funders within the European nations, and the European Commission.

The interdisciplinary community of ocean and coastal observers and modelers in Europe is driven by national observing needs for prediction and management of intricate processes shaping Europe’s Seas. Not all observing needs can be addressed by nations alone and various coordination activities exist to overcome fragmentation and create cross benefit within the European Ocean Observing Community (EOOC). This way critical insights into impacts of climate change on European Waters and cross border marine resources management can be achieved. Based on a large number of published material, this article is identifying and addressing the current state of activities of the EOOC and states gaps that potentially prevent efficacy. Key challenges include spatial and temporal coverage in observations, data integration, accessibility, uncertainties in projections, technological hurdles, and engagement and communication gaps. Detailed recommendations are provided for identified gaps, offering valuable insights for stakeholders, funders, and supporters of the EOOC. These recommendations, extending beyond academic interest, carry significant implications for climate change mitigation, marine resource management efficiency, ecosystem resilience, disaster preparedness, economic benefits, and the broader scientific advancements in European marine science, thereby benefiting society at large. As the world undergoes transformative changes impacting all facets of European life, substantial investment and support for the EOOC are crucial for precise information, accurate predictions, supporting sustained services that contribute to business growth and community resilience, and a sustainable ocean.

Ocean acidification is a global issue with particular regional significance in the California Current System, where social, economic, and ecological impacts are already occurring. Although ocean acidification is a concern that unifies the entire West Coast region, managing for this phenomenon at a regional scale is complex and further complicated by the large scale and dynamic nature of the region. Currently, data collection relevant to ocean acidification on the West Coast is piecemeal, and cannot capture the primary sources of variability in ocean acidification through time and across the region, hindering collaboration among regional managers. We developed a tool to analyze gaps in the West Coast ocean acidification monitoring network. We describe this tool and discuss how it can enable scientists and marine managers in the California Current System to fill information gaps and better understand and thus respond to ocean acidification through the implementation of management solutions at the local level.

The formation of Subantarctic Mode Water SAMW in the Southern Ocean plays a key role in the global oceanic uptake and storage of anthropogenic heat and carbon. Wintertime ocean surface heat loss is a dominant driver of Subantarctic Mode Water formation and variability, but wintertime air-sea flux observations in the Southern Ocean are extremely sparse. Recent advances in our understanding of the role of air-sea fluxes in Subantarctic Mode Water Formation from novel ocean observations are summarized here, particularly the role of synoptic atmospheric extreme events, and the drivers of interannual variations in SAMW. These advances in understanding have important implications for variability in Southern Ocean heat and carbon uptake, and can inform future Southern Ocean observing system design. This article is part of a discussion meeting issue 'Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities'. [ABSTRACT FROM AUTHOR]

With the growth of the Blue Economy, the volume of data collection within the ocean environment has been rapidly increasing. Larger numbers of oceanographic, meteorological, and floating Light Detection And Ranging (LiDAR) buoys have been collecting high fidelity measurements while pushing against power budget limits. Power limitations lead to infrequent transmission of reduced data sets or recording data to local storage that must be physically collected when the buoy is serviced. Triton Systems, Inc. and its partners are developing a retrofittable wave energy converter (WEC) to provide auxiliary power to these observation buoys to increase mission duration and power budget, improve reliability, and reduce the need for service trips. One of the greatest challenges has been developing a method to interface Triton's WEC with these buoys without impacting measurement fidelity. This is especially critical for inertial wave and LiDAR wind measurements collected with sensors that could be adversely affected by additional buoy dynamics introduced by an integrated WEC. To address this, Triton and EOM Offshore developed a compliant tether to pair an observation buoy with a floating WEC while decoupling relative motion. Based on EOM's proven stretch hose technology, this compliant tether transmits power and data between the buoy-WEC system. Modeling shows that the system has the potential to minimally adversely affect oceanographic, meteorological, wind resource characterization, and other measurements, with future testing scheduled to validate modeling efforts. [ABSTRACT FROM AUTHOR]

Since the Argo program began, 568 floats returned almost 31,000 profiles, at high‐southern latitudes, with no measured position. These data are either disseminated with positions linearly interpolated between known positions, or with no geographic positions. Here, we present a simple method for estimating unknown Argo float trajectories. We try to identify trajectories that approximately follow contours along three different properties: potential vorticity (f/H), sea‐level, and density at 1,000 m. No single property‐constraint can be used to estimate trajectories for all position‐gaps. Each constraint fails for 9%–18% of gaps, where no continuous contour between the end‐points exists. But all constraints fail for the same position‐gap, for fewer than 1% of cases. For a given position‐gap, when a trajectory is identified using two or three different constraints, we select the shortest trajectory to be used to "fill the gap". This selection process could be performed better by an Expert Operator, inspecting each estimated trajectory, and selecting the trajectory that is most consistent with a priori knowledge of the circulation in the vicinity of the position‐gap. Nonetheless, using the objective metric for selection, we find that 41.2% of position‐gaps use the f/H‐constraint, 32.1% use density, and 25.8% use sea‐level. We assess the estimated trajectories for consistency, by comparing bottom depths beneath trajectories to the deepest measurements in each profile. We find inconsistencies for 11.6% of position‐gaps using our method, compared to 28.0% using linearly‐interpolated trajectories. Adoption of the estimated trajectories for measurements under ice may yield benefits to many applications. Plain Language Summary: Argo floats measure ocean properties between the surface and 2,000 m depth, providing an estimate of their position using satellite fixes when they're at the surface. When a float samples under ice, it cannot measure its position. When that happens, the float continues to sample, collecting profiles over time, and later sends data if and when it finally surfaces. While under ice, the geographic positions of the float's observations are unknown, making it hard for scientists and marine users to exploit the data. Here, we present a method for estimating the float's position, while under ice, by assuming that the float's path followed contours of some climatological ocean properties. The method won't always be accurate, because floats mostly move with ocean properties that change with time. But sometimes, we expect the new estimates will be accurate enough to make the data more useful. Key Points: Almost 31,000 Argo profiles have sampled under ice at high‐southern latitudes, and are disseminated without measured positionsWe present a method to estimate missing trajectories, constrained by multiple different oceanic propertiesNo single property works for all cases. But using multiple constraints, realistic trajectories are estimated for almost all position‐gaps [ABSTRACT FROM AUTHOR]

The Deep Ocean Observing Strategy (DOOS) is an international, communitydriven initiative that facilitates collaboration across disciplines and fields, elevates a diverse cohort of early career researchers into future leaders, and connects scientific advancements to societal needs. DOOS represents a global network of deep-ocean observing, mapping, and modeling experts, focusing community efforts in the support of strong science, policy, and planning for sustainable oceans. Its initiatives work to propose deep-sea Essential Ocean Variables; assess technology development; develop shared best practices, standards, and cross-calibration procedures; and transfer knowledge to policy makers and deep-ocean stakeholders. Several of these efforts align with the vision of the UN Ocean Decade to generate the science we need to create the deep ocean we want. DOOS works toward (1) a healthy and resilient deep ocean by informing science-based conservation actions, including optimizing data delivery, creating habitat and ecological maps of critical areas, and developing regional demonstration projects; (2) a predicted deep ocean by strengthening collaborations within the modeling community, determining needs for interdisciplinary modeling and observing system assessment in the deep ocean; (3) an accessible deep ocean by enhancing open access to innovative low-cost sensors and open-source plans, making deep-ocean data Findable, Accessible, Interoperable, and Reusable, and focusing on capacity development in developing countries; and finally (4) an inspiring and engaging deep ocean by translating science to stakeholders/end users and informing policy and management decisions, including in international waters. [ABSTRACT FROM AUTHOR]

Abstract Since the Argo program began, 568 floats returned almost 31,000 profiles, at high‐southern latitudes, with no measured position. These data are either disseminated with positions linearly interpolated between known positions, or with no geographic positions. Here, we present a simple method for estimating unknown Argo float trajectories. We try to identify trajectories that approximately follow contours along three different properties: potential vorticity (f/H), sea‐level, and density at 1,000 m. No single property‐constraint can be used to estimate trajectories for all position‐gaps. Each constraint fails for 9%–18% of gaps, where no continuous contour between the end‐points exists. But all constraints fail for the same position‐gap, for fewer than 1% of cases. For a given position‐gap, when a trajectory is identified using two or three different constraints, we select the shortest trajectory to be used to “fill the gap”. This selection process could be performed better by an Expert Operator, inspecting each estimated trajectory, and selecting the trajectory that is most consistent with a priori knowledge of the circulation in the vicinity of the position‐gap. Nonetheless, using the objective metric for selection, we find that 41.2% of position‐gaps use the f/H‐constraint, 32.1% use density, and 25.8% use sea‐level. We assess the estimated trajectories for consistency, by comparing bottom depths beneath trajectories to the deepest measurements in each profile. We find inconsistencies for 11.6% of position‐gaps using our method, compared to 28.0% using linearly‐interpolated trajectories. Adoption of the estimated trajectories for measurements under ice may yield benefits to many applications.

As climate change and other anthropogenic impacts on marine ecosystems accelerate in the 21st century, there is an increasing need for sustained ocean time series. A robust and collaborative network of regional monitoring programs can detect early signs of unanticipated changes, provide a more holistic understanding of ecosystem responses, and prompt faster management actions. Fisheries-related surveys that collect fisheries-independent data (hereafter referred to as “fisheries surveys”) are a key pillar of sustainable fisheries management and are ubiquitous in the United States and other countries. From the perspective of ocean observing, fisheries surveys offer three key strengths: (1) they are sustained due to largely consistent funding support from federal and state public sector fisheries agencies, (2) they collect paired physical, chemical, and biological data, and (3) they have large and frequently overlapping spatial footprints that extend into the offshore region. Despite this, information about fisheries survey data collection can remain poorly known to the broader academic and ocean observing communities. During the 2019 CalCOFI Symposium, marking the 70th anniversary of the California Cooperative Oceanic Fisheries Investigations (CalCOFI), representatives from 21 ocean monitoring programs on the North American West Coast came together to share the status of their monitoring programs and examine opportunities to leverage efforts to support regional ecosystem management needs. To increase awareness about collected ocean observing data, we catalog these ongoing ocean time series programs and detail the activities of the nine major federal or state fisheries surveys on the U.S. West Coast. We then present three case studies showing how fisheries survey data contribute to the understanding of emergent ecosystem management challenges: marine heatwaves, ocean acidification, and contaminant spills. Moving forward, increased cross-survey analyses and cooperation can improve regional capacity to address emerging challenges. Fisheries surveys represent a foundational blueprint for ecosystem monitoring. As the international community moves toward a global strategy for ocean observing needs, fisheries survey programs should be included as data contributors.

Over fifteen years ago, Ocean Networks Canada (ONC) began with the world’s first large-scale, interactive, real-time portal into the ocean, bringing continuous, real-time data to the surface for applications in scientific research, societal benefits, and supporting Canada’s ocean industry. This marked the dawn of the Internet-connected ocean, enabling a more fulsome understanding of the ocean through ocean intelligence. These open data have improved our ability to monitor and understand our changing ocean offshore all three coasts of Canada, thanks to diversity of sensor systems to monitor earthquakes and tsunamis, deep sea biodiversity, whales, hydrothermal vents, neutrinos, ocean noise, ocean acidification, forensics experiments, and the impact of climate change, including sea ice thinning in the Arctic. This pioneering approach began in the late 1990s, when scientists began developing a new way of doing ocean science that was no longer limited by weather and ship-time. They imagined a permanent presence in the ocean of sensors to allow a continuous flow of ocean data via the Internet. This big science began to take shape early this century, when a partnership between United States and Canadian institutions was established. ONC evolved out of this international collaboration with seed funding from the Canada Foundation for Innovation, while in the United States, the Ocean Observatories Initiative (OOI) was funded. ONC works closely with OOI on that span the countries’ west coast border. Recently similar observing initiatives in Europe have begun, led by EMSO, which now has a close collaboration with ONC as an Associate Member.

The Joint Task Force, Science Monitoring And Reliable Telecommunications (JTF SMART) Subsea Cables, is working to integrate environmental sensors for ocean bottom temperature, pressure, and seismic acceleration into submarine telecommunications cables. The purpose of SMART Cables is to support climate and ocean observation, sea level monitoring, observations of Earth structure, and tsunami and earthquake early warning and disaster risk reduction, including hazard quantification. Recent advances include regional SMART pilot systems that are the first steps to trans-ocean and global implementation. Examples of pilots include: InSEA wet demonstration project off Sicily at the European Multidisciplinary Seafloor and water column Observatory Western Ionian Facility; New Caledonia and Vanuatu; French Polynesia Natitua South system connecting Tahiti to Tubaui to the south; Indonesia starting with short pilot systems working toward systems for the Sumatra-Java megathrust zone; and the CAM-2 ring system connecting Lisbon, Azores, and Madeira. This paper describes observing system simulations for these and other regions. Funding reflects a blend of government, development bank, philanthropic foundation, and commercial contributions. In addition to notable scientific and societal benefits, the telecommunications enterprise’s mission of global connectivity will benefit directly, as environmental awareness improves both the integrity of individual cable systems as well as the resilience of the overall global communications network. SMART cables support the outcomes of a predicted, safe, and transparent ocean as envisioned by the UN Decade of Ocean Science for Sustainable Development and the Blue Economy. As a continuation of the OceanObs’19 conference and community white paper (Howe et al., 2019, doi: 10.3389/fmars.2019.00424), an overview of the SMART programme and a description of the status of ongoing projects are given.

In this article, we present Bio-GO-SHIP, a new ocean observing program that will incorporate sustained and consistent global biological ocean observations into the Global Ocean Ship-based Hydrographic Investigations Program (GO-SHIP). The goal of Bio-GO-SHIP is to produce systematic and consistent biological observations during global ocean repeat hydrographic surveys, with a particular focus on the planktonic ecosystem. Ocean plankton are an essential component of the earth climate system, form the base of the oceanic food web and thereby play an important role in influencing food security and contributing to the Blue Economy. Despite its importance, ocean biology is largely under-sampled in time and space compared to physical and chemical properties. This lack of information hampers our ability to understand the role of plankton in regulating biogeochemical processes and fueling higher trophic levels, now and in future ocean conditions. Traditionally, many of the methods used to quantify biological and ecosystem essential ocean variables (EOVs), measures that provide valuable information on the ecosystem, have been expensive and labor- and time-intensive, limiting their large-scale deployment. In the last two decades, new technologies have been developed and matured, making it possible to greatly expand our biological ocean observing capacity. These technologies, including cell imaging, bio-optical sensors and 'omic tools, can be combined to provide overlapping measurements of key biological and ecosystem EOVs. New developments in data management and open sharing can facilitate meaningful synthesis and integration with concurrent physical and chemical data. Here we outline how Bio-GO-SHIP leverages these technological advances to greatly expand our knowledge and understanding of the constituents and function of the global ocean plankton ecosystem.

Understanding and sustainably managing complex environments such as marine ecosystems benefits from an integrated approach to ensure that information about all relevant components and their interactions at multiple and nested spatiotemporal scales are considered. This information is based on a wide range of ocean observations using different systems and approaches. An integrated approach thus requires effective collaboration between areas of expertise in order to improve coordination at each step of the ocean observing value chain, from the design and deployment of multi-platform observations to their analysis and the delivery of products, sometimes through data assimilation in numerical models. Despite significant advances over the last two decades in more cooperation across the ocean observing activities, this integrated approach has not yet been fully realized. The ocean observing system still suffers from organizational silos due to independent and often disconnected initiatives, the strong and sometimes destructive competition across disciplines and among scientists, and the absence of a well-established overall governance framework. Here, we address the need for enhanced organizational integration among all the actors of ocean observing, focusing on the occidental systems. We advocate for a major evolution in the way we collaborate, calling for transformative scientific, cultural, behavioral, and management changes. This is timely because we now have the scientific and technical capabilities as well as urgent societal and political drivers. The ambition of the United Nations Decade of Ocean Science for Sustainable Development (2021–2030) and the various efforts to grow a sustainable ocean economy and effective ocean protection efforts all require a more integrated approach to ocean observing. After analyzing the barriers that currently prevent this full integration within the occidental systems, we suggest nine approaches for breaking down the silos and promoting better coordination and sharing. These recommendations are related to the organizational framework, the ocean science culture, the system of recognition and rewards, the data management system, the ocean governance structure, and the ocean observing drivers and funding. These reflections are intended to provide food for thought for further dialogue between all parties involved and trigger concrete actions to foster a real transformational change in ocean observing.

Forward-backward smoothing based unknown input and state estimation for dynamic systems is studied in this paper, motivated by reconstruction of an oceanographic flow field using a swarm of buoyancy-controlled drifters. The development is conducted in a Bayesian framework. A Bayesian paradigm is constructed first to offer a probabilistic view of the unknown quantities given the measurements. Then a maximum a posteriori is established to build a means for simultaneous input and state smoothing, which can be solved by the classical Gauss–Newton method in the nonlinear case. Application to reconstruction of a complex three-dimensional flow field is presented and investigated via simulation studies. Copyright © 2014 John Wiley & Sons, Ltd.

As the use of aerial tools such as unmanned aerial vehicles (UAVs) for mangrove monitoring gains in popularity, understanding who leads this research and where is critical for expanding efficient monitoring methods and achieving international commitments to sustainable development, technology transfer and reduced inequality. Between 2000 and 2019, mangrove research using aerial tools was largely conducted in and led by institutions in higher income countries, despite High-income countries accounting for only 9% of global mangrove coverage. Of studies where the country of the lead institution differed from that of the study site, only 38% of the studies included local co-authors. These results echo historical patterns of research conducted by researchers from higher income countries on biodiversity concentrated in lower income countries, frequently with limited involvement of local scientists—known as “helicopter research.” The disconnect between where mangroves are located and where aerial research is conducted may result from barriers such as government restrictions, limited financial and technical resources, language barriers hindering UAV deployment, or hampered findability of local research. Our findings suggest that expertise for aerial surveys currently lies in “High-income, Annex II” and “Upper-middle-income, Non-Annex” countries, and both groups could invest time and resources in building local, long-term technological capacity in Upper-middle, Lower-middle and Low-income countries. We identify strategic partnerships to expand aerial tools for mangrove research that also address commitments under the United Nations Framework Convention on Climate Change and potential international collaborations under the framework proposed by the UN Decade of Ocean Science for Sustainable Development.

Ocean observing systems are well-recognized as platforms for long-term monitoring of near-shore and remote locations in the global ocean. High-quality observatory data is freely available and accessible to all members of the global oceanographic community—a democratization of data that is particularly useful for early career scientists (ECS), enabling ECS to conduct research independent of traditional funding models or access to laboratory and field equipment. The concurrent collection of distinct data types with relevance for oceanographic disciplines including physics, chemistry, biology, and geology yields a unique incubator for cutting-edge, timely, interdisciplinary research. These data are both an opportunity and an incentive for ECS to develop the computational skills and collaborative relationships necessary to interpret large data sets. Here, we use observatory data to demonstrate the potential for these interdisciplinary approaches by presenting a case study on the water-column response to anomalous atmospheric events (i.e., major storms) on the shelf of the Mid-Atlantic Bight southwest of Cape Cod, United States. Using data from the Ocean Observatories Initiative (OOI) Pioneer Array, we applied a simple data mining method to identify anomalous atmospheric events over a four-year period. Two closely occurring storm events in late 2018 were then selected to explore the dynamics of water-column response using mooring data from across the array. The comprehensive ECS knowledge base and computational skill sets allowed identification of data issues in the OOI data streams and technologically sound characterization of data from multiple sensor packages to broadly characterize ocean-atmosphere interactions. An ECS-driven approach that emphasizes collaborative and interdisciplinary working practices adds significant value to existing datasets and programs such as OOI and has the potential to produce meaningful scientific advances. Future success in utilizing ocean observatory data requires continued investment in ECS education, collaboration, and research; in turn, the ECS community provides feedback, develops knowledge, and builds new tools to enhance the value of ocean observing systems. These findings present an argument for building a community of practice to augment ECS ocean scientist skills and foster collaborations to extend the context, reach, and societal utility of ocean science.

Identifying spatially shared dynamics is a key component of community ecology studies as they provide evidence of common responses to environmental factors. We apply co-prediction, an empirical dynamic modeling method (EDM), where values in one time series are predicted from another to quantify shared dynamics in the California Cooperative Fishery Oceanographic Investigation (CalCOFI) dataset composed of spatially explicit physical and biological measurements. Co-prediction can arise in the absence of correlation between two time series. The survey dates to 1951 and consists of a semi-regular, fixed-station design off the west coast of the USA. While the California Current is a dynamic system with multiple identified regimes, we found evidence of coherence measured in terms of spatially shared dynamics in salinity, temperature, Shannon index of ichthyoplankton abundance, and single-species ichthyoplankton abundance throughout the CalCOFI survey area. Leave-one-out hindcast skill, without including any knowledge of shared dynamics was significant in 27 stations for salinity data, 36 for temperature data, and 33 for Shannon index (out of 81 total stations). We then evaluated hindcast skill when including shared dynamics via composite libraries, in which correlated or co-predicted time series are concatenated to produce denser attractors. The number of correlated stations was generally higher than the number of co-predicted stations, but hindcast skill from composite libraries of correlated stations did not increase hindcast skill. Composite libraries of co-predicted stations had significant leave-one-out hindcast skill in 60 stations for salinity data, 60 for temperature, and 72 for Shannon index. Additionally, we found evidence of nonlinear relationships, as nonlinear hindcasts accounted for nearly all of these significant stations. While there were high levels of correlation among stations, co-prediction proved a more robust method of identifying shared dynamics. Shared dynamics were largely concentrated south of Point Conception, considered an oceanographic and biological breakpoint, although in some cases shared dynamics spanned this boundary. Taken together, we apply EDM to present the first, to our knowledge, evaluation of station-specific hindcast skill and provide a view of the realized spatial structure occurring in the physical and biological dynamics of the California Current system.

Multidisciplinary, integrated ocean observing programs provide critical data for monitoring the effects of climate change on marine ecosystems. California Cooperative Oceanic Fisheries Investigations (CalCOFI) samples along the US West Coast and is one of the world’s longest-running and most comprehensive time series, with hydrographic and biological data collected since 1949. The pairing of ecological and physical measurements across this long time series informs our understanding of how the California Current marine ecosystem responds to climate variability. By providing a baseline to monitor change, the CalCOFI time series serves as a Keeling Curve for the California Current. However, challenges remain in connecting the data collected from long-term monitoring programs with the needs of stakeholders concerned with climate change adaptation (i.e., resource managers, policy makers, and the public), including for the fisheries and aquaculture sectors. We use the CalCOFI program as a case study to ask: how can long-term ocean observing programs inform ecosystem based management efforts and create data flows that meet the needs of stakeholders working on climate change adaptation? Addressing this question and identifying solutions requires working across sectors and recognizing stakeholder needs. Lessons learned from CalCOFI can inform other regional monitoring programs around the world, including those done at a smaller scale in developing countries.

The Global Ocean Observing System (GOOS) and its partners have worked together over the past decade to break down barriers between open-ocean and coastal observing, between scientific disciplines, and between operational and research institutions. Here we discuss some GOOS successes and challenges from the past decade, and present ideas for moving forward, including highlights of the GOOS 2030 Strategy, published in 2019. The OceanObs’09 meeting in Venice in 2009 resulted in a remarkable consensus on the need for a common set of guidelines for the global ocean observing community. Work following the meeting led to development of the Framework for Ocean Observing (FOO) published in 2012 and adopted by GOOS as a foundational document that same year. The FOO provides guidelines for the setting of requirements, assessing technology readiness, and assessing the usefulness of data and products for users. Here we evaluate successes and challenges in FOO implementation and consider ways to ensure broader use of the FOO principles. The proliferation of ocean observing activities around the world is extremely diverse and not managed, or even overseen by, any one entity. The lack of coherent governance has resulted in duplication and varying degrees of clarity, responsibility, coordination and data sharing. GOOS has had considerable success over the past decade in encouraging voluntary collaboration across much of this broad community, including increased use of the FOO guidelines and partly effective governance, but much remains to be done. Here we outline and discuss several approaches for GOOS to deliver more effective governance to achieve our collective vision of fully meeting society’s needs. What would a more effective and well-structured governance arrangement look like? Can the existing system be modified? Do we need to rebuild it from scratch? We consider the case for evolution versus revolution. Community-wide consideration of these governance issues will be timely and important before, during and following the OceanObs’19 meeting in September 2019.

The ocean is key to understanding societal threats including climate change, sea level rise, ocean warming, tsunamis, and earthquakes. Because the ocean is difficult and costly to monitor, we lack fundamental data needed to adequately model, understand, and address these threats. One solution is to integrate sensors into future undersea telecommunications cables. This is the mission of the SMART subsea cables initiative (Science Monitoring And Reliable Telecommunications). SMART sensors would “piggyback” on the power and communications infrastructure of a million kilometers of undersea fiber optic cable and thousands of repeaters, creating the potential for seafloor-based global ocean observing at a modest incremental cost. Initial sensors would measure temperature, pressure, and seismic acceleration. The resulting data would address two critical scientific and societal issues: the long-term need for sustained climate-quality data from the under-sampled ocean (e.g., deep ocean temperature, sea level, and circulation), and the near-term need for improvements to global tsunami warning networks. A Joint Task Force (JTF) led by three UN agencies (ITU/WMO/UNESCO-IOC) is working to bring this initiative to fruition. This paper explores the ocean science and early warning improvements available from SMART cable data, and the societal, technological, and financial elements of realizing such a global network. Simulations show that deep ocean temperature and pressure measurements can improve estimates of ocean circulation and heat content, and cable-based pressure and seismic-acceleration sensors can improve tsunami warning times and earthquake parameters. The technology of integrating these sensors into fiber optic cables is discussed, addressing sea and land-based elements plus delivery of real-time open data products to end users. The science and business case for SMART cables is evaluated. SMART cables have been endorsed by major ocean science organizations, and JTF is working with cable suppliers and sponsors, multilateral development banks and end users to incorporate SMART capabilities into future cable projects. By investing now, we can build up a global ocean network of long-lived SMART cable sensors, creating a transformative addition to the Global Ocean Observing System.

Well-founded data management systems are of vital importance for ocean observing systems as they ensure that essential data are not only collected but also retained and made accessible for analysis and application by current and future users. Effective data management requires collaboration across activities including observations, metadata and data assembly, quality assurance and control (QA/QC), and data publication that enables local and interoperable discovery and access and secures archiving that guarantees long-term preservation. To achieve this, data should be findable, accessible, interoperable, and reusable (FAIR). Here, we outline how these principles apply to ocean data and illustrate them with a few examples. In recent decades, ocean data managers, in close collaboration with international organizations, have played an active role in the improvement of environmental data standardization, accessibility, and interoperability through different projects, enhancing access to observation data at all stages of the data life cycle and fostering the development of integrated services targeted to research, regulatory, and operational users. As ocean observing systems evolve and an increasing number of autonomous platforms and sensors are deployed, the volume and variety of data increase dramatically. For instance, there are more than 70 data catalogs that contain metadata records for the polar oceans, a situation that makes comprehensive data discovery beyond the capacity of most researchers. To better serve research, operational, and commercial users, more efficient turnaround of quality data in known formats and made available through Web services is necessary. In particular, automation of data workflows will be critical to reduce friction throughout the data value chain. Adhering to the FAIR principles with free, timely, and unrestricted access to ocean observation data is beneficial for the originators, has obvious benefits for users, and is an essential foundation for the development of new services made possible with big data technologies.

Recurrent blooms of harmful algae and cyanobacteria (HABs) plague many coastal and inland waters throughout the United States and have significant socioeconomic impacts to the adjacent communities. Notable HAB events in recent years continue to underscore the many remaining gaps in knowledge and increased needs for technological advances leading to early detection. This review summarizes the main research and management priorities that can be addressed through ocean observation-based approaches and technological solutions for harmful algal blooms, provides an update to the state of the technology to detect HAB events based on recent activities of the Alliance for Coastal Technologies (ACT), offers considerations for ensuring data quality, and highlights both ongoing challenges and opportunities for solutions in integrating HAB-focused technologies in research and management. Specifically, technological advances are discussed for remote sensing (both multispectral satellite and hyperspectral); deployable in situ detection of HAB species on fixed or mobile platforms (based on bulk or taxa-specific biomass, images, or molecular approaches); and field-based and/or rapid quantitative detection of HAB toxins (via molecular and analytical chemistry methods). Suggestions for addressing challenges to continued development and adoption of new technologies are summarized, based on a consensus-building workshop hosted by ACT, including dealing with the uncertainties in investment for HAB research, monitoring, and management. Challenges associated with choosing appropriate technologies for a given ecosystem and/or management concern are also addressed, and examples of programs that are leveraging and combining complementary approaches are highlighted.

Development of global ocean observing capacity for the biological EOVs is on the cusp of a step-change. Current capacity to automate data collection and processing and to integrate the resulting data streams with complementary data, openly available as FAIR data, is certain to dramatically increase the amount and quality of information and knowledge available to scientists and decision makers into the future. There is little doubt that scientists will continue to expand their understanding of what lives in the ocean, where it lives and how it is changing. However, whether this expanding information stream will inform policy and management or be incorporated into indicators for national reporting is more uncertain. Coordinated data collection including open sharing of data will help produce the consistent evidence-based messages that are valued by managers. The GOOS Biology and Ecosystems Panel is working with other global initiatives to assist this coordination by defining and implementing Essential Ocean Variables. The biological EOVs have been defined, are being updated following community feedback, and their implementation is underway. In 2019, the coverage and precision of a global ocean observing system capable of addressing key questions for the next decade will be quantified, and its potential to support the goals of the UN Decade of Ocean Science for Sustainable Development identified. Developing a global ocean observing system for biology and ecosystems requires parallel efforts in improving evidence-based monitoring of progress against international agreements and the open data, reporting and governance structures that would facilitate the uptake of improved information by decision makers.

Our civilization needs a clean, resilient, productive, safe, well-observed, documented and predicted ocean. “The ocean we need for the future we want” was the motto of the Intergovernmental Oceanographic Commission proposal to the United Nations to consider the merit of an Ocean Science Decade. By proclaiming the Decade, the UN General Assembly offered the oceanographic community a unique, once in a life-time, opportunity to change the way we do things, make oceanography fit for purpose of effectively supporting sustainable development, and energize the ocean sciences for future generations. The Decade is the chance to put in place a more complete and sustainable observing system and feed the resulting data into a science-based informed decision-making system allowing increased reliance of our civilization on the ocean, its ecosystem services and, at the same time, preserving ocean health. Strong and proactive engagement of the oceanographic community in the design of the Decade and its observing component and subsequent energetic implementation of the ideas are sought. Participants in OceanObs’19 are invited to consider the additional possibilities and requirements associated with the Decade in their contributions to and brainstorming at the Conference. It is essential to use collective wisdom of OceanObs’19 to help developing an ambitious and also realistic implementation plan for the Decade, with a strong observational component.

Plankton are the base of marine food webs, essential to sustaining fisheries and other marine life. Continuous Plankton Recorders (CPRs) have sampled plankton for decades in both hemispheres and several regional seas. CPR research has been integral to advancing understanding of plankton dynamics and informing policy and management decisions. We describe how the CPR can contribute to global plankton diversity monitoring, being cost-effective over large scales and providing taxonomically resolved data. At OceanObs09 an integrated network of regional CPR surveys was envisaged and in 2011 the existing surveys formed the Global Alliance of CPR Surveys (GACS). GACS first focused on strengthening the dataset by identifying and documenting CPR best practices, delivering training workshops, and developing an integrated database. This resulted in the initiation of new surveys and manuals that enable regional surveys to be standardized and integrated. GACS is not yet global, but it could be expanded into the remaining oceans; tropical and Arctic regions are a priority for survey expansion. The capacity building groundwork is done, but funding is required to implement the GACS vision of a global plankton sampling program that supports decision-making for the scientific and policy communities. A key step is an analysis to optimize the global sampling design. Further developments include expanding the CPR for multidisciplinary measurements via additional sensors, thus maximizing the ship-of-opportunity platform. For example, defining pelagic ecoregions based on plankton and ancillary data could support high seas Marine Protected Area design. Fulfillment of Aichi Target 15, the United Nation’s Sustainable Development Goals, and delivering the Essential Ocean Variables and Essential Biodiversity Variables that the Global Ocean Observing System and Group on Earth Observation’s Biodiversity Observation Network have, respectively, defined requires the taxonomic resolution, spatial scale and time-series data that the CPR approach provides. Synergies with global networks exploiting satellite data and other plankton sensors could be explored, realizing the Survey’s capacity to validate earth observation data and to ground-truth emerging plankton observing platforms. This is required for a fully integrated ocean observing system that can understand global ocean dynamics to inform sustainable marine decision-making.

The oceans play a key role in global issues such as climate change, food security, and human health. Given their vast dimensions and internal complexity, efficient monitoring and predicting of the planet’s ocean must be a collaborative effort of both regional and global scale. A first and foremost requirement for such collaborative ocean observing is the need to follow well-defined and reproducible methods across activities: from strategies for structuring observing systems, sensor deployment and usage, and the generation of data and information products, to ethical and governance aspects when executing ocean observing. To meet the urgent, planet-wide challenges we face, methods across all aspects of ocean observing should be broadly adopted by the ocean community and, where appropriate, should evolve into “Ocean Best Practices.” While many groups have created best practices, they are scattered across the Web or buried in local repositories and many have yet to be digitized. To reduce this fragmentation, we introduce a new open access, permanent, digital repository of best practices documentation (oceanbestpractices.org) that is part of the Ocean Best Practices System (OBPS). The new OBPS provides an opportunity space for the centralized and coordinated improvement of ocean observing methods. The OBPS repository employs user-friendly software to significantly improve discovery and access to methods. The software includes advanced semantic technologies for search capabilities to enhance repository operations. In addition to the repository, the OBPS also includes a peer reviewed journal research topic, a forum for community discussion and a training activity for use of best practices. Together, these components serve to realize a core objective of the OBPS, which is to enable the ocean community to create superior methods for every activity in ocean observing from research to operations to applications that are agreed upon and broadly adopted across communities. Using selected ocean observing examples, we show how the OBPS supports this objective. This paper lays out a future vision of ocean best practices and how OBPS will contribute to improving ocean observing in the decade to come.

Animal telemetry is a powerful tool for observing marine animals and the physical environments that they inhabit, from coastal and continental shelf ecosystems to polar seas and open oceans. Satellite-linked biologgers and networks of acoustic receivers allow animals to be reliably monitored over scales of tens of meters to thousands of kilometers, giving insight into their habitat use, home range size, the phenology of migratory patterns and the biotic and abiotic factors that drive their distributions. Furthermore, physical environmental variables can be collected using animals as autonomous sampling platforms, increasing spatial and temporal coverage of global oceanographic observation systems. The use of animal telemetry, therefore, has the capacity to provide measures from a suite of essential ocean variables (EOVs) for improved monitoring of Earth's oceans. Here we outline the design features of animal telemetry systems, describe current applications and their benefits and challenges, and discuss future directions. We describe new analytical techniques that improve our ability to not only quantify animal movements but to also provide a powerful framework for comparative studies across taxa. We discuss the application of animal telemetry and its capacity to collect biotic and abiotic data, how the data collected can be incorporated into ocean observing systems, and the role these data can play in improved ocean management.

The Ocean Observatories Initiative (OOI) is an integrated network that enables scientific investigation of interlinked physical, chemical, biological and geological processes throughout the global ocean. With near real-time data delivery via a common Cyberinfrastructure, the OOI instruments two contrasting ocean systems at three scales. The Regional Cabled Array instruments a tectonic plate and overlying ocean in the northeast Pacific, providing a permanent electro-optical cable connecting multiple seafloor nodes that provide high power and bandwidth to seafloor sensors and moorings with instrumented wire crawlers, all with speed-of-light interactive capabilities. Coastal arrays include the Pioneer Array, a relocatable system currently quantifying the New England shelf-break front, and the Endurance Array, a fixed system off Washington and Oregon with connections to the Regional Cabled Array. The Global Arrays host deep-ocean moorings and gliders to provide interdisciplinary measurements of the water column, mesoscale variability, and air-sea fluxes at critical high latitude locations. The OOI has unique aspects relevant to the international ocean observing community. The OOI uses common sensor types, verification protocols, and data formats across multiple platform types in diverse oceanographic regimes. OOI observing is sustained, with initial deployment in 2013 and 25 years of operation planned. The OOI is distributed among sites selected for scientific relevance based on community input and linked by important oceanographic processes. Scientific highlights include real-time observations of a submarine volcanic eruption, time-series observations of methane bubble plumes from Southern Hydrate Ridge off Oregon, observations of anomalous low-salinity pulses off Oregon, discovery of new mechanisms for intrusions of the Gulf Stream onto the shelf in the Middle Atlantic Bight, documentation of deep winter convection in the Irminger Sea, and observations of extreme surface forcing at the most southerly surface mooring in the world ocean.

Comprehensive and objective evaluation of all observing assets, tools, and services within an ocean observing system is essential to maximize effectiveness and efficiency; yet, it often eludes programs due to the complexity of such robust evaluation. In order to address this need, the Pacific Islands Ocean Observing System (PacIOOS) transformed an evaluation matrix developed for the energy sector to one suitable for ocean observing. The resulting innovation is a decision analysis methodology that factors in multiple attributes (market, risk, and performance factors) and allows for selective weighting of attributes based on system maturity, external forcing, and consumer demand. This evaluation process is coupled with an annual review of priorities with respect to stakeholder needs and the program’s 5-year strategic framework in order to assess the system’s components. The results provide information needed to assess the effectiveness, efficiency, and impact of each component within the system, and informs a decision-making process that determines additional investment, refinement, sustainment, or retirement of individual observing assets, services, or component groups. Regularly evaluating, and taking action to improve, modify, or terminate weak system components allows for the continuous improvement of PacIOOS services by ensuring resources are directed to the priorities of the stakeholder community. The methodology described herein is presented as an innovative opportunity for others looking for a systematic approach to evaluate their observing systems to inform program-level decision-making as they develop, refine, and distribute data and information products.

This paper reviews the design of the Tropical Pacific Observing System (TPOS) and its governance and takes a forward look at prospective change. The initial findings of the TPOS 2020 Project embrace new strategic approaches and technologies in a user-driven design and the variable focus of the Framework for Ocean Observing. User requirements arise from climate prediction and research, climate change and the climate record, and coupled modeling and data assimilation more generally. Requirements include focus on the upper ocean and air-sea interactions, sampling of diurnal variations, finer spatial scales and emerging demands related to biogeochemistry and ecosystems. One aim is to sample a diversity of climatic regimes in addition to the equatorial zone. The status and outlook for meeting the requirements of the design are discussed. This is accomplished through integrated and complementary capabilities of networks, including satellites, moorings, profiling floats and autonomous vehicles. Emerging technologies and methods are also discussed. The outlook highlights a few new foci of the design: biogeochemistry and ecosystems, low-latitude western boundary currents and the eastern Pacific. Low latitude western boundary currents are conduits of tropical-subtropical interactions, supplying waters of mid to high latitude origin to the western equatorial Pacific and into the Indonesian Throughflow. They are an essential part of the recharge/discharge of equatorial warm water volume at interannual timescales and play crucial roles in climate variability on regional and global scales. The tropical eastern Pacific, where extreme El Niño events develop, requires tailored approaches owing to the complex of processes at work there involving coastal upwelling, and equatorial cold tongue dynamics, the oxygen minimum zone and the seasonal double Intertropical Convergence Zone. A pilot program building on existing networks is envisaged, complemented by a process study of the East Pacific ITCZ/warm pool/cold tongue/stratus coupled system. The sustainability of TPOS depends on effective and strong collaborative partnerships and governance arrangements. Revisiting regional mechanisms and engaging new partners in the context of a planned and systematic design will ensure a multi-purpose, multi-faceted integrated approach that is sustainable and responsive to changing needs.

The Indian River Lagoon (IRL) is a large and complex barrier island estuary on Florida's East coast. The system is also one of the nation's most biologically diverse, a major spawning and nursery ground for numerous species of fish and shellfish, and home to significant populations of dolphins and manatees. Ocean observing systems can play an integral role in evaluating the effects of both natural (e.g. climate change) and anthropogenic impacts (e.g. nutrient pollution) on such a complex system. In this paper we present an integrated multidisciplinary approach to studying the recurrent large-scale harmful algal bloom (HAB) events that have threatened both the ecological and economic stability of the IRL and represent a significant public health hazard. Due to the complex biological, chemical and physical interactions associated with IRL HABs, the integration of classical observing methodology, such as phytoplankton surveys, with real-time water quality monitoring, innovative technology, and biological sentinels, is essential. The open sharing of data for research, education and public engagement is another key component of our approach. There are multiple stakeholders and end users that rely on these efforts to understand HAB dynamics in a unique marine system. [ABSTRACT FROM AUTHOR]

In the last 10 years, new monitoring and modelling technologies have emerged allowing real-time observation and forecasting of the coastal ocean at regional and local scales. These technologies are at the core of multi-platform integrated observing and forecasting systems, such as the Balearic Islands Coastal Ocean Observing and Forecasting System (SOCIB). New capabilities to characterise the state of the ocean and its variability at finer spatial and temporal scales are emerging, supporting science and products for society. SOCIB has a well-defined mission to deliver ocean observing for the benefit of science and society. From initiation in 2010, SOCIB has provided high-quality, free and open data. In order to increase our utility, we developed a Products and Services Strategy rooted in business best practice. Ten sectors – groups of users with common data needs – were identified, for which SOCIB has information and knowledge of high value. Dedicated products were developed in cooperation with the end-users: beach lifeguards/managers and sustainable marine resources managers. We illustrate an integrative approach, combining business concepts with collaborative software development methodologies and ocean observing science, to turn ocean observations and forecasts into products and services, with benefits for society in the sustainable blue economy era. [ABSTRACT FROM AUTHOR]

Abstract The Mackenzie River flows into the Arctic Ocean via a complex network of channels, creating a plume that dominates water properties over the southern Beaufort Sea shelf. Observations of temperature, salinity, water level elevations and currents collected in August 2007 and August 2010 are used to investigate the circulation and structure of the river plume, during periods with predominantly easterly/offshore winds. The measurements were collected from instrument platforms in a river channel, in shallow water of 2–6 m depth (10–25 km from the coastline), from a research vessel, and from satellites. The observations indicate that moderate atmospheric forcing, including sea level pressure changes of 1–2 kPa and easterly alongshore wind stress (< 0.1 Nm − 2 ), is sufficient to induce a 0.2–0.3 m set-down of the mean water level and surface currents up to 0.6 ms − 1 . A theoretical model of the water level at the delta suggests that local wind stress is the primary driver of sea level variability. The observations show that the region is stratified with a shallow river surface plume at the surface, and winds primarily cause offshore transport of the plume up to 30 km per day. Winds also cause separation of the plume from the coast and onshore transport of shelf water near the bottom that induces local changes in temperature of up to 12 o C. River water is the primary source of heat, and therefore sea surface temperatures in the coastal ocean are strongly determined by the inflowing freshwater temperatures. The coastal plume responds to atmospheric forcing over timescales of less than 1 day, leading to rapid development of strong currents and large fluctuations in water mass properties in the shallow region across the submarine delta. Highlights • In situ and remotely sensed observations of an Arctic river plume were collected. • Wind-driven sea level fluctuations and strong surface currents were observed. • The coastal region is strongly stratified with a shallow river plume at the surface. • Riverine heat flux dominates the heat budget of the continental shelf. • The plume responds to atmospheric forcing over timescales of less than a day. [ABSTRACT FROM AUTHOR]

Harvey entered the Gulf of Mexico as a tropical depression on 23 August 2017; two days later it had strengthened to a category 1 hurricane. Over the following 30 hr Harvey rapidly intensified, reaching the Texas Bight as a category 3 storm. This intensification continued while Harvey crossed the shelf, making landfall as a category 4 storm 60 km east of Corpus Christi, TX on 26 August. A hydrographic survey two weeks prior to landfall shows that the tropical cyclone heat potential across the Texas Bight was approximately 35 kJ/cm2, which is 55 kJ/cm2 less than the amount of upper ocean heat normally associated with intensification. Combined with buoy, float, and satellite data, we use hydrographic surveys to study the conditions of the Texas Bight that contributed to Harvey's rapid intensification. We find that, at the time of landfall, the Texas Bight was well mixed with very warm water extending from the surface to bottom. As a consequence, mixing induced by Harvey had a small impact on surface temperatures which remained high and supported continued intensification. The results show that tropical cyclone heat potential is not an effective metric for hurricane intensity prediction in shallow water, and illustrate the need for continuous subsurface monitoring in order to improve hurricane forecasts. Plain Language Summary: Hurricanes rely on heat extracted from the upper ocean as their energy source. When the ocean is warm conditions are more favorable and hurricanes are often stronger. Hurricanes also mix the ocean which brings cold water from greater depth and can lead to intensity reduction. Tropical cyclone heat potential is a measure of heat in the upper ocean which is available as an energy source for hurricanes. In shallow water tropical cyclone heat potential is typically low because there is not as much water to store heat; therefore, hurricanes are not expected to intensify over shallow water. In this paper we show that hurricane Harvey did intensify over the shallow water off the Texas coast despite having low heat potential. Using ocean measurements, we found that the reason was because the ocean was very warm from the surface to the seabed. Therefore, when Harvey mixed the ocean very little cold water was brought up from below and the surface remained warm which allowed Harvey to continue to strengthen. Results suggest that tropical cyclone heat potential is ineffective for estimating hurricane strength in shallow water and demonstrates the importance of knowing subsurface temperatures if we want to improve hurricane forecasts. Key Points: Hurricane Harvey intensified over the shallow water of the Texas Bight despite being a region of low tropical cyclone heat potentialPeak season, warm, well‐mixed shelf water limits sea surface cooling and helps contribute to hurricane intensificationTropical cyclone heat potential has limited usefulness in shallow water; therefore, subsurface ocean observations are essential for increasing the accuracy of hurricane intensity forecasts [ABSTRACT FROM AUTHOR]