General Anomaly Detection of Underwater Gliders Validated by Large-scale Deployment Datasets

Underwater gliders have been widely used in oceanography for a range of applications. However, unpredictable events like shark strikes or remora attachments can lead to abnormal glider behavior or even loss of the instrument. This paper employs an anomaly detection algorithm to assess operational conditions of underwater gliders in the real-world ocean environment. Prompt alerts are provided to glider pilots upon detecting any anomaly, so that they can take control of the glider to prevent further harm. The detection algorithm is applied to multiple datasets collected in real glider deployments led by the University of Georgia's Skidaway Institute of Oceanography (SkIO) and the University of South Florida (USF). In order to demonstrate the algorithm generality, the experimental evaluation is applied to four glider deployment datasets, each highlighting various anomalies happening in different scenes. Specifically, we utilize high resolution datasets only available post-recovery to perform detailed analysis of the anomaly and compare it with pilot logs. Additionally, we simulate the online detection based on the real-time subsets of data transmitted from the glider at the surfacing events. While the real-time data may not contain as much rich information as the post-recovery one, the online detection is of great importance as it allows glider pilots to monitor potential abnormal conditions in real time.Comment: Accepted in IEEE/MTS OCEANS Gulf Coast 202

Anomaly Detection of Underwater Gliders Verified by Deployment Data

This paper utilizes an anomaly detection algorithm to check if underwater gliders are operating normally in the unknown ocean environment. Glider pilots can be warned of the detected glider anomaly in real time, thus taking over the glider appropriately and avoiding further damage to the glider. The adopted algorithm is validated by two valuable sets of data in real glider deployments, the University of South Florida (USF) glider Stella and the Skidaway Institute of Oceanography (SkIO) glider Angus.Comment: 10 pages, 16 figures, accepted by the International Symposium on Underwater Technology (UT23

Real-time Autonomous Glider Navigation Software

Underwater gliders are widely utilized for ocean sampling, surveillance, and other various oceanic applications. In the context of complex ocean environments, gliders may yield poor navigation performance due to strong ocean currents, thus requiring substantial human effort during the manual piloting process. To enhance navigation accuracy, we developed a real-time autonomous glider navigation software, named GENIoS Python, which generates waypoints based on flow predictions to assist human piloting. The software is designed to closely check glider status, provide customizable experiment settings, utilize lightweight computing resources, offer stably communicate with dockservers, robustly run for extended operation time, and quantitatively compare flow estimates, which add to its value as an autonomous tool for underwater glider navigation.Comment: OCEANS 2023 Limeric

Continental shelf seafloor mapping, benthic habitat surveys, and reef fish assessments in the eastern Gulf of Mexico

In April 2010, The Deepwater Horizon (DWH) oil spill originated in the deep sea 1,500 m below the ocean surface at the edge of the continental shelf off Louisiana. Surface and sub-surface dispersal of the oil eventually encompassed an area of over 200,000 km2. Impacts of DWH on biota of the Gulf of Mexico were severe, wide-spread, and are ongoing even a decade after the spill. Because of its offshore origin, the spill caused injury to many resources on the continental shelf, including important reef fish species (e.g., snappers and groupers, etc.) and protected species including sea turtles. Habitats which these species occupy were oiled which resulted in the loss of key supporting plant and animal species. Because so little of the offshore habitat of reef fish species and sea turtles was mapped and characterized prior to the spill, restoration efforts aimed at improving degraded habitats and strengthening species populations proved difficult. This project was specifically developed to discover additional, high conservation value, habitats of reef fishes and sea turtles on the continental shelf of the Gulf of Mexico off Florida (the West Florida Shelf, WFS). The goal of the project was to map such habitats and quantify the density and biodiversity of species occupying them, and to facilitate additional conservation management decisions to enhance their long-term sustainability. The project resulted in mapping and classifying and characterizing 2,350 km2 of heretofore unmapped habitats, the development of new methods to extrapolate habitat types from a sub-sample from video surveys, and new technologies to automate the counting and identification of fish species and habitat features using artificial intelligence. Project personnel have presented these materials to the competent management authorities responsible for fish and sea turtle management. Here we provide technical detail on the methods, procedures and findings from this project.Funded by the National Fish and Wildlife Foundation (NFWF) Gulf Environmental Benefit Fund (2015 - 2020

Seafloor Geodesy in Shallow Water With GPS on an Anchored Spar Buoy

Measuring seafloor motion in shallow coastal water is challenging due to strong and highly variable oceanographic effects. Such measurements are potentially useful for monitoring near‐shore coastal subsidence, subsidence due to petroleum withdrawal, strain accumulation/release processes in subduction zones and submerged volcanoes, and certain freshwater applications, such as volcano deformation in caldera‐hosted lakes. We have developed a seafloor geodesy system for this environment based on an anchored spar buoy topped by high‐precision GPS. Orientation of the buoy is measured using a digital compass that provides heading, pitch, and roll information. The combined orientation and GPS tracking data are used to recover the three‐dimensional position of the seafloor marker (anchor). A test system has been deployed in Tampa Bay, Florida, for over 1 year and has weathered several major storms without incident. Even in the presence of strong tidal currents which can deflect the top of the buoy several meters from vertical, daily repeatability in the corrected three‐component position estimates for the anchor is 1–2 cm or better.Published12116–121401IT. Reti di monitoraggio e sorveglianzaJCR Journa

Multi-year observations of Breiðamerkurjökull, a marine-terminating glacier in southeastern Iceland, using terrestrial radar interferometry

Terrestrial radar interferometry (TRI) is a new technique for studying ice motion and volume change of glaciers. TRI is especially useful for temporally and spatially dense measurements of highly dynamic glacial termini. We conducted a TRI survey of Breiðamerkurjökull, a marine-terminating glacier in Iceland, imaging its terminus near the end of the melt season in 2011, 2012 and 2013. The ice velocities were as high as 5 m d−1, with the fastest velocities near the calving front. Retreat of the glacier over the 3 year observation period was accompanied by strong embayment formation. Iceberg tracking with the radar shows high current velocities near the embayment, probably indicating strong meltwater outflow and mixing with relatively warm lagoon water

The Application of Novel Research Technologies by the Deep Pelagic Nekton Dynamics of the Gulf of Mexico (DEEPEND) Consortium

The deep waters of the open ocean represent a major frontier in exploration and scientific understanding. However, modern technological and computational tools are making the deep ocean more accessible than ever before by facilitating increasingly sophisticated studies of deep ocean ecosystems. Here, we describe some of the cutting-edge technologies that have been employed by the Deep Pelagic Nekton Dynamics of the Gulf of Mexico (DEEPEND; www.deependconsortium.org) Consortium to study the biodiverse fauna and dynamic physical-chemical environment of the offshore Gulf of Mexico (GoM) from 0 to 1,500 m

A Multidisciplinary Approach to Investigate Deep-Pelagic Ecosystem Dynamics in the Gulf of Mexico Following Deepwater Horizon

The pelagic Gulf of Mexico (GoM) is a complex system of dynamic physical oceanography (western boundary current, mesoscale eddies), high biological diversity, and community integration via diel vertical migration and lateral advection. Humans also heavily utilize this system, including its deep-sea components, for resource extraction, shipping, tourism, and other commercial activity. This utilization has had impacts, some with disastrous consequences. The Deepwater Horizon oil spill (DWHOS) occurred at a depth of ∼1500 m (Macondo wellhead), creating a persistent and toxic mixture of hydrocarbons and dispersant in the deep-pelagic (water column below 200 m depth) habitat. In order to assess the impacts of the DWHOS on this habitat, two large-scale research programs, described herein, were designed and executed. These programs, ONSAP and DEEPEND, aimed to quantitatively characterize the oceanic ecosystem of the northern GoM and to establish a time-series with which natural and anthropogenic changes could be detected. The approach was multi-disciplinary in nature and included in situ sampling, acoustic sensing, water column profiling and sampling, satellite remote sensing, AUV sensing, numerical modeling, genetic sequencing, and biogeochemical analyses. The synergy of these methodologies has provided new and unprecedented perspectives of an oceanic ecosystem with respect to composition, connectivity, drivers, and variability

Salinity and temperature measurements from an oceanographic glider deployed in the northeastern Gulf of Mexico, cruise DP02, August 2015

A Slocum Glider was deployed within the DEEPEND study area near the time of the DEEPEND cruise DP02 in August 2015. As the glider traverses its transit path, it makes measurements at various depths from ~2m to almost 1000m. The measurements include conductivity, temperature, depth, chlorophyll, dissolved O2, and light field measurements. While the glider is deployed at sea, it surfaces and communicates to an onshore control station at predetermined intervals. A decimated selection of vehicle and science measurement is transmitted during these surface transmissions, and the relevant data becomes available through a USF web site. After the glider’s recovery at the end of the deployment, the complete measurement suite is downloaded from the vehicle and processed, and also becomes available through the USF site as well as a national data archive. The data available during and after the deployment can help correlate the regional NRL hydrographic model and the satellite imagery to in situ measurements of subsurface water characteristics. The Slocum glider data for the DP02 deployment can be found at the Integrated Ocean Observing System (IOOS) glider data website, https://data.ioos.us/gliders/erddap/tabledap/Murphy-20150809T1355Z.html (Dataset ID: Murphy-20150809T1355Z, USF) The glider was deployed from the RV Point Sur on August 9, 2015 at ~12:45 UTC, at approx. 27°N, 89°W. Its initial transit was to the North (to ~ 28°N, 88.5°W). The glider operated at up to 200m depth until 2300 on 10 Aug., when the dive profiles were changed to 400m. The programmed path brought it to the Loop Current. Encountering the increased speed of the Loop Current waters, it was transported to the North, then East, before being advected to the South. The glider was programmed to cross the Loop Current and exit it to the East. Strong density stratification and communication problems resulted in the glider remaining within the Loop Current’s influence and it was unable to clear the current until far to the South of the planned survey area. It was recovered on 22 August, near 25.5°N, 86.5°W

Salinity and temperature measurements from an oceanographic glider deployed in coordination with DEEPEND Cruise DP04, August 2016

A Slocum Glider was deployed in the northern Gulf of Mexico near the time of the DEEPEND cruise DP04 (August 10-17, 2016). As the glider traverses its transit path, it makes measurements at various depths from ~2m to almost 1000m. The measurements include conductivity, temperature, depth, pressure, and salinity. While the glider is deployed at sea, it surfaces and communicates to an onshore control station at predetermined intervals. A selection of vehicle and science measurement is transmitted during these surface transmissions, and the relevant data becomes available through a University of South Florida (USF) web site. After the glider’s recovery at the end of the deployment, the complete measurement suite is downloaded from the vehicle and processed, and also becomes available through the USF site as well as a national data archive. The data available during and after the deployment can help correlate the regional Naval Research Laboratory (NRL) hydrographic model and the satellite imagery to in situ measurements of subsurface water characteristics