Ocean Observing System Research Articles

An Ocean Observing and Prediction Experiment in Prince William Sound, Alaska

The observing and forecasting conditions of coastal oceans in Alaska is technically challenging because of the mountainous terrain, the notoriously stormy seas, and a complex hydrological system of freshwater from rivers and glaciers. The Alaska Ocean Observing System and their partners developed a demonstration project over a 5-yr period in Prince William Sound. This location was chosen because of historical efforts to monitor ocean circulation following the Exxon Valdez oil spill of 1989. The primary goal is to develop a quasi-operational system that delivers weather and ocean information in near–real time to diverse user communities. This observing system now consists of a spatial array of atmospheric and oceanic sensors and a new generation of computer models to numerically simulate and forecast weather, waves, and ocean circulation. The project culminated in a 2009 field experiment that evaluated the performance of the model forecasts. Three ships, 44 surface drifters, an underwater glider, and an autonomous underwater vehicle, as well as two shore-based surface current radar systems, augmented the routine atmospheric and oceanographic measurements from weather stations and oceanographic buoys. Observations from terrestrial and moored weather stations were compared with atmospheric circulation forecasts, and wave gauges provided data that were used to evaluate the forecasts of significant wave heights and periods. The radar current mappers and drifter buoys validated the surface ocean circulation forecasts. Improved observations and forecasts of coastal oceans will benefit oil spill responders, commercial shippers that convey large amounts of freight to and from Alaska, and U.S. Coast Guard search-and-rescue operations.

Haracterizing the Effects of Two Storms on the Coastal Waters of O‘ahu, Hawai‘i, Using Data from the Pacific Islands Ocean Observing System

haracterizing the Effects of Two Storms on the Coastal Waters of O‘ahu, Hawai‘i, Using Data from the Pacific Islands Ocean Observing System

Anomaly Detection in Environmental Monitoring Networks [Application Notes

We apply a recently developed model for anomaly detection to sensor data collected from a single node in the Heron Island wireless sensor network, which in turn is part of the Great Barrier Reef Ocean Observation System. The collection period spanned six hours each day from February 21 to March 22, 2009. Cyclone Hamish occurred on March 9, 2009, roughly in the middle of the collection period. Our system converts sensor measurements to elliptical summaries. Then a dissimilarity image of the data is built from a measure of focal distance between pairs of ellipses. Dark blocks along the diagonal of the image suggest clusters of ellipses. Finally, the single linkage algorithm extracts clusters from the dissimilarity data. We illustrate the model with three two-dimensional subsets of the three dimensional measurements of (air) pressure, temperature and humidity. Our examples show that iVAT images of focal distance are a reliable basis for estimating cluster structures in sets of ellipses, and that single linkage can successfully extract the indicated clusters. In particular, we are able to clearly isolate the cyclone Hamish event with this method, which demonstrates the ability of our model to detect anomalies in environmental monitoring networks.

The Northwest Association of Networked Ocean Observing Systems and opportunities for acoustical applications.

NANOOS, the Pacific Northwest Regional Association of the U.S. Integrated Ocean Observing System (IOOS), aims to provide coastal ocean observations improving understanding and enabling decisions to improve safety, enhance the economy, and protect the environment. Biological aspects of ocean observing lag behind physical because of the difficulty of observing animal behavior beneath the surface; yet information about the behavior and survival of marine species in the ocean is identified as a critical need for fisheries management and marine spatial planning. Acoustics are poised to contribute to this need; however, limitations of acoustic arrays must be addressed. NANOOS recognizes opportunities for acoustical applications and has begun exploring these. NANOOS and POST deployed an acoustic receiver on a seaglider to test feasibility of using gliders to extend the scope of acoustic tracking arrays into deeper water and as a rapid deployment technology to test fixed arrays and investigate oceanographic features. During a 3‐month test deployment, July–October 2010, a receiver mounted on the seaglider worked flawlessly and made two detections: one from a salmon and one from a Humboldt squid. NANOOS has proposed to develop methods for integrating instruments for tracking migrations of fish and marine mammals into ocean observing networks.

Building the oceanic concert hall: Multidisciplinary applications of acoustics for ocean observing systems.

Over the past decade, the oceanographic community has been constructing integrated multidisciplinary observational systems to serve the immediate and long‐term needs of the society (www.ioos.gov). The overarching goal is to provide practical products and information to society as a return on its long‐term investment in oceanographic research. Demand is increasing for information about the state of our oceans to address a myriad of issues ranging from climate variability to fisheries management to public education. Customers for ocean observing systems range from government agencies to commercial shipping companies to the science projects of high school students. Two developing “observing systems” in the Pacific Northwest are the Northwest Association of Networked Ocean Observing Systems (www.nanoos.org) and the Neptune Undersea Cable Network (www.interactiveoceans.washington.edu). The oceans are largely transparent to sound; hence, oceanographic, biological, and signal‐processing acoustic techniques are primary tools for ocean observation and engineering. The opportunities and value of acoustical observations and techniques within these systems are boundless, yet incorporation of these techniques has been opportunistic and ad hoc. Coordination of the acoustical applications is essential. Organizations advocating acoustical observations face enormous challenges of planning, implementation, and data management to bring acoustical tools to fruition for ocean observing systems.

Closing the loop – Approaches to monitoring the state of the Arctic Mediterranean during the International Polar Year 2007–2008

During the 4th International Polar Year 2007–2009 (IPY), it has become increasingly obvious that we need to prepare for a new era in the Arctic. IPY occurred during the time of the largest retreat of Arctic sea ice since satellite observations started in 1979. This minimum in September sea ice coverage was accompanied by other signs of a changing Arctic, including the unexpectedly rapid transpolar drift of the Tara schooner, a general thinning of Arctic sea ice and a double-dip minimum of the Arctic Oscillation at the end of 2009. Thanks to the lucky timing of the IPY, those recent phenomena are well documented as they have been scrutinized by the international research community, taking advantage of the dedicated observing systems that were deployed during IPY. However, understanding changes in the Arctic System likely requires monitoring over decades, not years. Many IPY projects have contributed to the pilot phase of a future, sustained, observing system for the Arctic. We now know that many of the technical challenges can be overcome. The Norwegian projects iAOOS-Norway, POLEWARD and MEOP were significant ocean monitoring/research contributions during the IPY. A large variety of techniques were used in these programs, ranging from oceanographic cruises to animal-borne platforms, autonomous gliders, helicopter surveys, surface drifters and current meter arrays. Our research approach was interdisciplinary from the outset, merging ocean dynamics, hydrography, biology, sea ice studies, as well as forecasting. The datasets are tremendously rich, and they will surely yield numerous findings in the years to come. Here, we present a status report at the end of the official period for IPY. Highlights of the research include: a quantification of the Meridional Overturning Circulation in the Nordic Seas (“ the loop”) in thermal space, based on a set of up to 15-year-long series of current measurements; a detailed map of the surface circulation as well as characterization of eddy dispersion based on drifter data; transport monitoring of Atlantic Water using gliders; a view of the water mass exchanges in the Norwegian Atlantic Current from both Eulerian and Lagrangian data; an integrated physical–biological view of the ice-influenced ecosystem in the East Greenland Current, showing for instance nutrient-limited primary production as a consequence of decreasing ice cover for larger regions of the Arctic Ocean. Our sea ice studies show that the albedo of snow on ice is lower when snow cover is thinner and suggest that reductions in sea ice thickness, without changes in sea ice extent, will have a significant impact on the arctic atmosphere. We present up-to-date freshwater transport numbers for the East Greenland Current in the Fram Strait, as well as the first map of the annual cycle of freshwater layer thickness in the East Greenland Current along the east coast of Greenland, from data obtained by CTDs mounted on seals that traveled back and forth across the Nordic Seas. We have taken advantage of the real-time transmission of some of these platforms and demonstrate the use of ice-tethered profilers in validating satellite products of sea ice motion, as well as the use of Seagliders in validating ocean forecasts, and we present a sea ice drift product – significantly improved both in space and time – for use in operational ice-forecasting applications. We consider real-time acquisition of data from the ocean interior to be a vital component of a sustained Arctic Ocean Observing System, and we conclude by presenting an outline for an observing system for the European sector of the Arctic Ocean.

States’ obligations relating to marine monitoring and observation

Ocean data determining the state of the ocean are required for various purposes. The data are needed to understand the ocean and its interrelation, for instance, with the climate as well as to provide information and benefits for numerous sectors, such as for the coastal protection or pollution control. In order to meet the multiple needs for ocean information, a global and sustained system for ocean observation activities is necessary. Steps towards such a global system have been taken within the last decades, especially by setting up the Global Ocean Observing System (GOOS). However, the existing international structures and systems have been lacking governmental support and are held to be insufficient. In this context, the questions are raised whether states are already required by international law to observe and monitor the ocean and to cooperate in doing so and whether states are even obliged to contribute to international ocean observing programmes. Although to some extent, states’ obligations can be found in international conventions, such as in the UN Convention on the Law of the Sea (UNCLOS), they cannot meet all the various needs for ocean data. Specific and substantive obligations in international law meeting the multiple needs for ocean data are, however, required. If such obligations were included in the UNCLOS, issues relating to Marine Scientific Research would have to be kept in mind. Another option of creating specific commitments could be seen in a new agreement relating to the GOOS.

Interdisciplinary Ocean Observing on the Texas Coast

AbstractThe Integrated Ocean Observing System® is necessary to oceanography and vital for understanding spatial and temporal scales of important environmental and climate processes. However, many state-of-the-art ocean observing system (OOS) technologies are operationally constrained in shallow coastal waters. Texas A&M University (TAMU) researchers are overcoming the constraint by combining traditional platforms with modern shipboard OOS. Shipboard observations provide the spatial context and are complemented by moored observations providing the temporal context of spatial observations. In the northern Gulf of Mexico (GOM), OOS provide researchers with large, continuous spatial and temporal data sets to investigate naturally occurring environmental events. The summer of 2010 has been a unique season for researchers in the GOM with the British Petroleum oil spill off the Louisiana coast and the shift of seasonal wind and precipitation events along the western GOM coastline impacting the formation and sustainability of a common hazard on the Texas‐Louisiana shelf—hypoxia. Such events have and are currently emphasizing an environmental revitalization of coastal GOM OOS to better monitor and predict unexpected events directly impacting coastal waters. This manuscript describes TAMU’s existing interdisciplinary operating OOS and supplemental instrumentation added to address spatial and temporal scales of northern GOM coastal hazards. Details also will be included in TAMU’s future directions as an OOS leader on the Texas shelf and in how OOS plays vital role in community education and awareness of the coastal oceans.

Advances in the Ocean Observing System in the Gulf of Maine: Technical Capabilities and Scientific Results

AbstractThe Northeastern Regional Association of Coastal Ocean Observing Systems (NERACOOS), which began in 2008, includes the University of Maine’s comprehensive data buoy array in the Gulf of Maine (GoM). The University of Maine buoy system started in 2001 as part of the Gulf of Maine Ocean Observing System (GoMOOS). The buoys provide a wide variety of oceanographic and marine meteorological data in real time to scientists, environmentalists, the National Weather Service, the U.S. Coast Guard and Canadian Coast Guard, educators, regional natural resource managers, the GoM fishing and maritime industries, and the general public. The GoM observing system is presently undergoing a redesign of the buoy control system to enhance remote access and reduce operational costs. The enhancements will allow remote trouble-shooting and reprogramming of the buoys and subsurface sensors. The system will also accommodate sensors from other research groups and allow them post-deployment control without assistance from our buoy group.Over the near-decade of operation, the system has revealed marked seasonal and interannual variability of the circulation and physical properties of the GoM. In the fall of 2004 to spring of 2005, Doppler currents measured an outflow of deep salty slope waters that suggest a regime shift in the inflow and outflow of transports through the Northeast Channel. During the same period, a salinity anomaly event lowered salinity throughout the GoM by roughly 2 psu by the winter of 2005. In following years, the previously unusual slope outflow and reduced salinity have often reoccurred.

The Global Ocean Observing Component of IOOS: Implementation of the Initial Global Ocean Observing System for Climate and the Path Forward

AbstractThe global ocean observing system for climate, which comprises the global in situ component of the U.S. Integrated Ocean Observing System, has now achieved about 61% of its initial design goal. Although this observing system, implemented cooperatively by over 70 countries worldwide, serves multiple applications, it is designed primarily to address climate requirements defined by the international Global Climate Observing System. The U.S. contribution to the system, described here, is implemented as an interdependent set of observational subsystems that constitute about half of the over 8,000 observing platforms deployed by the world community. Although much work remains to complete the initial global observing system, scientific advances of the past decade have identified the need to deploy a second-generation system that integrates biogeochemical and ecological observations with the primarily physical and carbon-related oceanographic observations that form the backbone of the initial observing system.

Regional Objective Analysis for Merging High-Resolution MERIS, MODIS/Aqua, and SeaWiFS Chlorophyll- a Data From 1998 to 2008 on the European Atlantic Shelf

In this paper, we define the method that is used to merge high-resolution multisensor chlorophyll-a (chl-a) data on the Ireland-Biscay-Iberia Regional Ocean Observing System area from 1998 to the present at a resolution of 1.1 km. The method is based on geostatistics and is known as kriging. The merged variable is the daily anomaly of chl-a, with the anomaly being defined as the difference between the daily image and the mean historical field for the considered day. For each day, the continuous anomaly image is generated using the kriging method, and the mean historical field is then added to obtain the cloudless field of chl- a. The initial satellite chl-a data set used in the merging procedure is derived from the daily level-2 water leaving radiances of three ocean color sensors: the Sea-Viewing Wide Field of View Sensor on the Orbview platform, the Moderate Resolution Imaging Spectroradiometer on the Aqua platform, and the Medium Resolution Imaging Spectrometer Instrument on the ENVISAT platform. The chl-a concentration is obtained using a specific algorithm developed by Ifremer, known as OC5 product. Before merging, each satellite-derived chl-a product has been compared to in situ data and has been validated using a matchup data set. After this validation against in situ data, intercomparisons between the satellite data sets have been performed. As the chl-a anomaly variability depends, in this region, on the season and the distance from the shore, local space-time semivariograms have been calculated to estimate the spatiotemporal dependence or covariance of the chlorophyll anomalies. The semivariograms, used in the estimation of the kriged anomaly, are defined by their nuggets (noise), their spatial and temporal range (maximum distance for a nonnull covariance between the anomalies), and their sill (maximum variance). The spatial range of the semivariogram has been approximated locally on a regular grid. The nuggets and the sills have been deduced from the square of the mean of the chl-a concentration (the climatological reference) as we have observed a classical proportionality effect between the square of the chl-a mean, the variance of the distribution, and the parameters of the semivariograms. Compared to each original product, the analysis shows a complete coverage and differences with the in situ data that are statistically equivalent to those observed with the initial satellite data set. The merged product offers a number of applications for environmental monitoring such as the monitoring of the eutrophication risk required by the Water Framework Directive of the European Union.

Information from low-density expendable bathythermograph transects: North Atlantic mean temperature structure and quasi-decadal variability

The 1999 Ocean Observing System conference recommended that the Low density (LD) expendable bathythermograph (XBT) network be discontinued contingent on the completion of studies showing that the global Argo network and/or satellite altimetry can provide equivalent information. Herein, information content in North Atlantic LD lines relative to quasi-decadal variability in upper layer temperature structure is addressed as the first step in achieving this recommendation. Two LD lines are located in the subpolar gyre and support results from previous studies of shorter length that ocean advection and not only air–sea fluxes plays an important role, particularly in the eastern gyre, in determining the characteristics of the water masses transported to the source regions of North Atlantic Deep Water. Several sections cross the Gulf Stream and Labrador Current. They provide evidence to support the hypothesis that changes in the intensity of Labrador Current properties cause meridional motions of the Gulf Stream. Decadal variability in the subtropical gyre of the North Atlantic has been attributed to westward propagation of temperature anomalies by the mean currents and planetary waves. Modeling studies suggest that these signals are dominant in the thermocline at the northern latitudes (order 30°) of the subtropical gyre. Similar calculations from a line crossing the subtropical gyre at these same latitudes shows no indication of westward propagation. Quasi-decadal signals in upper layer temperature are coincident across the entire gyre with some suggestion of eastward motion of temperature anomalies. One line on the southern boundary of the subtropical gyre does include westward signal movement from the eastern boundary. Based on the information content of individual lines, recommendations are made relative to the continuation of specific transects until it has been demonstrated that Argo and satellite altimetry can provide equivalent results.

A Regional Slocum Glider Network in the Mid-Atlantic Bight Leverages Broad Community Engagement

AbstractAutonomous underwater gliders have proven to be a cost-effective technology for measuring the 3-D ocean and now represent a critical component during the design and implementation of the Mid-Atlantic Regional Ocean Observing System (MARCOOS), a Region of the U.S. Integrated Ocean Observing System. The gliders have been conducting regional surveys of the Mid-Atlantic (MA) Bight, and during the 3 years of MARCOOS, the glider fleet has conducted 22 missions spanning 10,867 km and collecting 62,824 vertical profiles of data. In addition to collecting regional data, the gliders have facilitated collaboration for partners outside of MARCOOS. The existence of the MA glider observatory provided a unique test bed for cyber-infrastructure tools being developed as part of the National Science Foundation’s Ocean Observatory Initiative. This effort allowed the Ocean Observatory Initiative software to integrate the MARCOOS assets and provided a successful demonstration of an ocean sensor net. The hands-on experience of the MA glider technicians supported training and provided assistance of collaborators within the Caribbean Regional Association, also a region of the U.S. Integrated Ocean Observing System, to assess the efficacy of gliders to resolve internal waves. Finally, the glider fleet has enabled sensor development and testing in a cost-effective manner. Generally, new sensors were tested within the MARCOOS domain before they were deployed in more extreme locations throughout the world’s oceans. On the basis of this experience, the goal of the MARCOOS glider team will be to expand the MA network in coming years. The potential of how an expanded network of gliders might serve national needs was illustrated during the 2010 Macondo Gulf of Mexico oil spill, where gliders from many institutions collected subsurface mesoscale data to support regional models and oil response planning. The experience gained over the last 5 years suggests that it is time to develop a national glider network.

The U.S. Integrated Ocean Observing System in a Global Context

AbstractThe mission of the U.S. Integrated Ocean Observing System (IOOS®) is to deliver socioeconomic benefits through provision of readily accessible, systematic, and timely data and information about the past, present, and future state of the waters of the open ocean, the U.S. Exclusive Economic Zone, the U.S. coastal waters, and the Great Lakes. The safety, economic, and environmental benefits that can be derived in whole or in part from IOOS data and information are diverse. They range from maritime and coastal zone applications that are the primary mission of the U.S. IOOS endeavor to a broad range of much wider national benefits, such as the contribution of ocean data and information to improved weather prediction and climate projection. Fully realizing these benefits depends on the U.S. IOOS being connected to other domains of earth and atmospheric observation within the United States and to international frameworks and programs. This article outlines the structure and socioeconomic goals of the U.S. IOOS and explores how fulfilling the IOOS mission contributes to and depends upon connections to the Global Ocean Observing System and the Global Earth Observation System of Systems.

Operation and Application of a Regional High-Frequency Radar Network in the Mid-Atlantic Bight

AbstractThe Mid-Atlantic Regional Coastal Ocean Observing System (MARCOOS) High-Frequency Radar Network, which comprises 13 long-range sites, 2 medium-range sites, and 12 standard-range sites, is operated as part of the Integrated Ocean Observing System. This regional implementation of the network has been operational for 2 years and has matured to the point where the radars provide consistent coverage from Cape Cod to Cape Hatteras. A concerted effort was made in the MARCOOS project to increase the resiliency of the radar stations from the elements, power issues, and other issues that can disable the hardware of the system. The quality control and assurance activities in the Mid-Atlantic Bight have been guided by the needs of the Coast Guard Search and Rescue Office. As of May 4, 2009, these quality-controlled MARCOOS High-Frequency Radar totals are being served through the Coast Guard’s Environmental Data Server to the Coast Guard Search and Rescue Optimal Planning System. In addition to the service to U.S. Coast Guard Search and Rescue Operations, these data support water quality, physical oceanographic, and fisheries research throughout the Mid-Atlantic Bight.

Integrated Ocean Observing System in Support of Forecasting Harmful Algal Blooms

AbstractHarmful algal bloom (HAB) events threaten human health, living marine resources, and ecosystem health. Their occurrence has increased in frequency, duration, and severity over the last several decades. Preventing, controlling, or mitigating the impacts of HABs requires the development of permanent, operational ocean observing systems that continuously provide the data and information necessary for rapid detection and timely forecasts of changes in ecosystem states. Key elements of such observing systems are observations and modeling that must be efficiently linked via data management and communication networks. Building the observing system begins by integrating existing assets, is followed by incorporation of new technologies and knowledge, and is guided by the data and information needs of decision makers. User needs are particularly important for development of operational forecast models and new sensors for measuring required biological (e.g., HAB species abundance) and chemical (e.g., concentrations of HAB toxins) variables in near real time. This article describes operational observing system requirements for a HAB forecasting system and current efforts by Regional Associations to develop these observing systems for targeted species in their respective regions.

The Integrated Ocean Observing System High-Frequency Radar Network: Status and Local, Regional, and National Applications

AbstractA national high-frequency radar network has been created over the past 20 years or so that provides hourly 2-D ocean surface current velocity fields in near real time from a few kilometers offshore out to approximately 200 km. This preoperational network is made up of more than 100 radars from 30 different institutions. The Integrated Ocean Observing System efforts have supported the standards-based ingest and delivery of these velocity fields to a number of applications such as coastal search and rescue, oil spill response, water quality monitoring, and safe and efficient marine navigation. Thus, regardless of the operating institution or location of the radar systems, emergency response managers, and other users, can rely on a common source and means of obtaining and using the data. Details of the history, the physics, and the application of high-frequency radar are discussed with successes of the integrated network highlighted.

Knowledge through partnerships: integrating marine protected area monitoring and ocean observing systems

Escalating concern over the state of coastal marine ecosystems highlights the need for a better understanding of how such systems are structured by physical, biological, and chemical processes, and how human activities interact with these processes. Marine protected area (MPA) networks are being established around the world, in an effort to protect marine populations, communities, and ecosystems. Concurrently, ocean observing systems (OOSs) are being developed and implemented to identify and describe changes in the coastal oceans. Because marine ecosystems are strongly influenced by oceanographic processes, proper interpretation of ecological data to assess MPA performance requires information generated by coastal OOSs. At the same time, OOSs designed with the goal of identifying ecosystem responses to climate change require information from long‐term ecological monitoring studies of MPAs. Collaborative integration between ecological and oceanographic monitoring programs is central to elucidating both the role of MPAs for conservation and the influence of climate change on marine ecosystems.

Wave Heights during Hurricane Katrina: An Evaluation of PPP and PPK Measurements of the Vertical Displacement of the GPS Antenna

Abstract In August 2005 the eye of Hurricane Katrina passed 49 n mi to the west of a 3-m discus buoy operated by the Central Gulf of Mexico Ocean Observing System (CenGOOS). Buoy motions were measured with a strapped-down 6 degrees of freedom accelerometer, a three-axis magnetometer, and a survey-grade GPS receiver. The significant wave heights were computed from the buoy’s accelerometer record and from the dual-frequency GPS measurements that were processed in two different ways. The first method was postprocessed kinematic (PPK) GPS, which requires another GPS receiver at a fixed known location, and the other was precise point positioning (PPP) GPS, which is another postprocessed positioning technique that yields absolute rather than differential positions. Unlike inertial measurement units, either GPS technique can be used to obtain both waves and water levels. The purpose of this note is to demonstrate the excellent reliability and accuracy of both methods for determining wave heights and periods from a GPS record. When the motion of the GPS antenna is properly understood as the motion of the buoy deck and not the true vertical motion of the sea surface, the GPS wave heights are as reliable as a strapped-down 1D accelerometer.

Serving data from the SCAR Southern Ocean Observing System (SOOS) using the SeaDataNet infrastructure

Abstract. The Scientific Committee on Antarctic Research (SCAR) and the Scientific Committee on Oceanic Research (SCOR) jointly intend to build a Southern Ocean Observing System (SOOS). This paper addresses the required data flow infrastructure. SOOS will use a system of systems approach, using existing observation programmes and projects. Data should be submitted to professional data centres. The problem arises how to link all these data centres and get a central overview of the SOOS data as well as direct access to the data. The Netherlands National Oceanographic Data Committee (NL-NODC) has successfully built a national distributed oceanographic data acccess infrastructure, adopting and implementing technology developed by the European SeaDataNet project. The Dutch system has been operational since early 2009. The conclusion is that the SeaDataNet technology can be used to build an operational, distributed data delivery infrastructure, featuring all elements required by the Southern Ocean Observing System (SOOS).