Last fall, the Coastal Endurance team conducted an initial test run of a Slocum G3 glider to determine its capabilities and operational differences to the G2 glider, currently used by the Endurance and Coastal & Global Scale Nodes (CGSN) teams. The test was prompted by glider vendor Teledyne’s announcement that it would no longer support the G2 glider past 2023.
Both the Endurance and CGSN teams have since expanded testing. The Endurance team recently completed a two-month deployment of a G3 glider, with plans to deploy another later this summer. The CGSN team, which operates the Pioneer and two global arrays, is testing three G3 gliders. One is being tested for use as a coastal glider at the Pioneer Array and the other two are being configured for the Irminger Sea and Station Papa global sites.
“Recent testing at the Pioneer Array was really valuable for us,” said Peter Brickley, CGSN Observatory Operations Lead. “We got a chance to see that our missions were workable, we found and made the changes that were needed, and we were also able to get a better estimate of how much energy these things were going to use.”
[media-caption path="https://oceanobservatories.org/wp-content/uploads/2021/07/IMG_3107-2-1-scaled.jpg" link="#"]Diana Wickman of the CGSN team at Woods Hole Oceanographic Institution is responsible for keeping the CGSN gliders operational. Here she has stripped the exterior of the glider to ensure that all internal parts are functional. Once refurbished, the gliders are tested in a water tank before being deployed at sea. Credit: Jade Lin ©WHOI.[/media-caption]The G3 gliders use more power than the G2 gliders, so the logistics of when and where they are deployed will require some adjustments. When powered by primary lithium batteries, for example, the G2 gliders can be deployed for about 90 days. The initial tests of the G3 gliders showed they could last in the water for around 75 days using primary lithium batteries. For trial runs using rechargeable batteries, the time in the water for the G3 gliders was reduced to about 30 days.
OOI is working with the vendor to evaluate operational alternatives to extend the operating window of the G3 gliders.
Improvements may require tweaking
“The rechargeable batteries are a really cool feature, but because they are about half of the energy density of the usual batteries, we’re going to have to adjust sampling schemes and plans for time in the water when we use the rechargeable batteries,” said Stuart Pearce, who works with the Endurance gliders. For now, the Endurance team intends to test the rechargeable batteries in the near shore gliders in the spring and summer when they can reliably get out to sea to recover and deploy the gliders.
G3 gliders also come equipped with larger volume buoyancy pumps than the G2 models in response to users’ feedback. “The gliders rise and fall in the water column by changing their volume and therefore density,” explained Pearce. “The new gliders have 800-1000 cubic centimeters of fluid volume to rise and dive with, compared to the 500 cubic centimeters of volume in the G2 gliders. This means that the G3 gliders can climb and dive in a greater buoyancy range.” One option being explored is whether power consumption can be reduced by adjusting the volume of the reservoir fluid needed to make the glider rise and fall.
The new G3 gliders incorporate some changes that address feedback from OOI and other users who have operated G2 gliders. “If you put anything in the ocean and use it as much as we do, you will find things that unexpectedly fail,” said Peter Brickley, CGSN Observatory Operations Lead. “We’ve been operating gliders since 2013, so we have lots of experience. In the early days, for example, we had a lot of problems with the digifin, the steering rudder that’s on the back of the vehicle. We worked closely with Teledyne to document and study this issue and they ultimately made needed improvements.” Other issues have been similarly addressed over the years.
Integrating the new G3 gliders into its Global Arrays may offer greater reliability as older G2 models are phased out. Diana Wickman, Senior Engineering Assistant II at Woods Hole Oceanographic Institution who keeps the CGSN gliders operational, explained “We need the equipment to work really well, and it needs to work for the entire year. At Pioneer, if we have problems, we can replace vehicles that are struggling with vehicles that we can refurbish in-house, but we simply can’t do that at the global sites.”
For now, the teams will continue with testing to make sure the new gliders will work for OOI’s purpose of long-term ocean monitoring.
OOI shares its glider data with the Integrated Ocean Observing System (IOOS) Glider Data Assembly Center and the OceanGliders project, which is a part of the Global Ocean Observing System (GOOS). Both serve as repositories for researchers interested in using glider data.
A very engaged group of participants spent the week of June 21st thinking about how to optimize the Pioneer Array for its relocation to the southern Mid-Atlantic Bight (MAB) in 2024. The five-day Innovations Lab, sponsored by the National Science Foundation (NSF) was led by the OOIFB (Ocean Observatories Initiative Facilities Board), a talented team of “Sparks”, Knowinnovation, Inc. (KI), and expertly supported by the OOI Facility. The group identified a range of representative interdisciplinary science questions that can be addressed using the Pioneer Array within the MAB and proposed optimum locations and potential configurations for the array.
Science question topics included air-sea interactions; the influence of estuarine plumes and the Gulf Stream on cross-shelf and shelf-slope exchanges and their impacts on ocean chemistry and biology; benthic-pelagic coupling; and canyon processes. Participants converged on a general region (see boxes in Figure 1 below) that would best address the science questions.
[media-caption path="https://oceanobservatories.org/wp-content/uploads/2021/06/Google-earth-map.png" link="#"]Figure 1. Southern MAB Pioneer Array regions. The red box indicates the region where moorings would be located and the larger green box indicates the region where mobile assets (gliders and AUVs) would operate.[/media-caption]
“The Innovations Lab was very successful, and we really appreciate the community sharing their innovative ideas with us in this essential first step,” said Kendra Daly, chair of the OOIFB. “The Innovations Lab provides an excellent start to a long process of fleshing out the details to ensure that the array provides data to investigate a broad range of interdisciplinary science questions, while also being robust enough to weather the challenging environmental conditions in the Mid-Atlantic Bight.”
The OOIFB will continue to engage with the OOI community to refine the array’s design for implementation over the next two years. The Innovations Lab showed that there is strong community interest in coastal science, the potential for new partnerships, and excitement about implementing the Pioneer Array in its new location.
Applications to apply for the Pioneer Array Innovations Lab 2 are due on May 31st. The Lab will be held each day during the week of June 21-25 (about 5-6 hours each day). During this Lab, participants will work to identify the observatory opportunities that can be offered by the Pioneer Array at its new location at the Mid-Atlantic Bight. Details are provided below.
The application form for the Pioneer Array Innovations Lab 2 is available here.
To learn more or to apply, please visit here.
It’s official, the next location of the OOI (Ocean Observatories Initiative) Coastal Pioneer Array is the Mid-Atlantic Bight (MAB) and the move will take place in 2024. The geographic footprint championed during the NSF-sponsored Innovations Lab #1 is the region of the MAB between Cape Hatteras and Norfolk Canyon. This region offers opportunities to collect data on a wide variety of cross-disciplinary science topics including cross-shelf exchange, land-sea interactions associated with large estuarine systems, a highly productive ecosystem with major fisheries, and carbon cycle processes. This location also offers opportunities to improve our understanding of hurricane development, tracking and prediction, and offshore wind partnerships.
As background, the OOI has been in full operations since 2016. The OOI Pioneer Array was designed to be relocatable, and in 2020 the Ocean Observatories Initiative Facilities Board (OOIFB) and the National Science Foundation (NSF) launched a process to select the next OOI Pioneer Array location. A Phase 1 Innovations Lab was held in March 2021 to explore possible locations based on scientific questions of interest. The inputs received helped NSF make its decision to select the MAB.
A second (Phase 2) Innovations Lab is scheduled for the week of June 21-25. During this Lab, participants will work to further identify and refine the opportunities afforded by the new Pioneer Array location. Selected participants will be exploring how the Pioneer Array sensors and platforms can be optimized to achieve science and education goals at the new site, based on environmental, logistical, and infrastructural considerations. Partnership and collaboration potentials at the new location will also be discussed. The OOIFB, in partnership with Know Innovations, will again be facilitating the second Innovation Lab.
The ocean community is invited to help identify new design considerations that can enable exciting research endeavors at the chosen location. Scientists, educators, and other stakeholders are encouraged to apply for the Phase 2 Innovations Lab. Please visit the OOIFB website for more information.