A Three Stream Ocean Optics Model

A Three Stream Ocean Optics Model: Regional Implementation and Validation. Adapted by OOI from Miller M., 2022. 

[media-caption path="https://oceanobservatories.org/wp-content/uploads/2023/07/EA-science-highlight.png" link="#"](Figure 3.10 from Miller (2022) Top: The black line shows the mean OOI absorption as a function of wavelength for OOI Endurance CSPP Oregon shelf deployment 15 (August – Sept 2019). The gray shading shows the OOI absorption extent between the 20% and 80 % quantiles. The tan shading shows the maximum and minimum extent of OOI absorption. The colored lines correspond to the modeled absorption for different single species approximations. Bottom: Same as top, but for scattering instead of absorption.[/media-caption]

Miles Miller used OOI data as part of this MS thesis awarded September 2022 from the Univ. California, Santa Cruz.  The goal of his work was to develop the potential to estimate phytoplankton community structure from remotely sensed optical information and not direct in situ phytoplankton observations. As a step towards this goal, he estimated phytoplankton community structure using spectrally dependent optical absorption and scattering data from an AC-S on the Oregon Shelf profiler. Miller developed linear relationships between modeled phytoplankton absorption and scattering and corresponding observations and solved them by constrained least squares inversion over a field of thirteen wavelengths using six phytoplankton types.  He solved the problem for independent absorption and scattering as well as coupled absorption and scattering. He estimated phytoplankton communities as a function of profile depth and for multiple profiles in time.

The model produced accurate downward irradiance fields when using observed absorption and scattering profiles obtained from the Ocean Observatories Initiative’s Oregon Shelf Surface Piercing Profiler Mooring. Through this forward modeling-based comparison to observations it was found that the optical model can produce accurate profiles under certain conditions, making it promising for data assimilation of remote sensing reflectance as a function of wavelength.  Miller identified several outstanding issues remaining to be addressed to move from using in situ measured absorption and scattering to estimates from remote sensing reflectance.  Because the optical model accuracy is primarily dependent on absorption and scattering, he argued that remote sensing reflectance accuracy can be improved with enhanced phytoplankton community structure and CDOM estimations (see Figure 3.10 from Miller (2022). This figure shows that the modeled phytoplankton light attenuation agrees well with the measurements but that modeled absorption underestimates measurements. This underestimation hints that chromophoric dissolved organic matter (CDOM) is not being properly resolved as CDOM affects only total absorption and not scattering.

_________________________________________

Miller, M. (2022). A Three Stream Ocean Optics Model: Regional Implementation and Validation (master’s thesis). University of California, Santa Cruz. 62 pp.

Read More

Collaborative Data Partnership Providing Fuller, More Robust Picture of Conditions in Northeast Pacific

A new data initiative involving more than 20 years of oceanographic data from Olympic Coast National Marine Sanctuary (OCNMS) promises to provide scientists and the public with a more robust picture of changing ocean conditions within the sanctuary and Northeast Pacific Ocean.

Funded by the National Oceanic and Atmospheric Administration’s (NOAA) Climate Program Office, a team from Oregon State University is working to make 23 years of sanctuary mooring data and data from CTD (Conductivity, Temperature, and Depth) casts available through publicly accessible data repositories. The three-year project will also combine the sanctuary’s data with complementary data sets in the region, including data from the Ocean ObservatorIes Initiative (OOI) Coastal Endurance Array.

“The OCNMS data are a critically important data set that has not been fully unlocked and represents a treasure chest of information that we’ve only begun to crack open,” said Jenny Waddell, research coordinator at Olympic Coast National Marine Sanctuary and a collaborator on the project. “The data will provide information about marine heat waves, changes in timing of spring transition to upwelling, seasonal hypoxia, and ocean acidification, all of which will help improve the management of marine resources in the sanctuary.”

Olympic Coast National Marine Sanctuary, along Washington State’s outer coast, represents one of North America’s most productive marine ecosystems.  An area of summertime upwelling of cold nutrient-rich waters, the sanctuary hosts a diverse ecosystem that is home to many commercially and culturally important fisheries.

[media-caption path="https://oceanobservatories.org/wp-content/uploads/2023/06/SP_stern_JWaddell_Aug2021.jpeg" link="#"]The stern of the R/V Storm Petrel hints at some of the enhanced capacity that this new vessel brings to research on the Olympic Coast, including a larger work area on the back deck, an upper deck for seabird and mammal surveys, a new pot hauler and knuckle boom crane, and a much more capable A-frame and winch.  Credit: Jenny Waddell © NOAA.[/media-caption]

Collected by 10 oceanographic moorings, the process of taking 23 years of the sanctuary’s quality-controlled data (water temperature, salinity, density, spiciness, velocity, and dissolved oxygen concentration) and meshing them with data from 700 CTD casts is a huge undertaking that will be conducted in multiple steps. The first step was the handover of all processed and raw data by the sanctuary to data experts Brandy Cervantes and Craig Risien at OSU. The data experts, who are Co-PIs on the NOAA project, are going through all the data and reprocessing where necessary to make sure that all the data are interoperable. The high-resolution CTD data are of particular interest, having never been made widely available before. These data will provide information about the water column to complement and validate the data collected by the instruments on the moorings.

OOI’s Contribution

The Coastal Endurance Array’s Washington Inshore mooring is the shallowest of the three OOI moorings off Washington State and lies just inside the sanctuary’s southern boundary. This location helps provide an in-depth look at ongoing conditions nearer the coast. While the other two Endurance Array moorings off Washington State are farther offshore and to the south, not formally within the sanctuary boundaries, they provide valuable year-round data, which are particularly helpful for context on conditions farther offshore from the sanctuary and for regional forecasting and prediction efforts of ocean conditions.  Sanctuary moorings are seasonal, collecting data when they are deployed in May through the first week of October when they are recovered, except for a single overwintering mooring, so OOI data also provide important year-round context for OCNMS.

“Data from the other two Endurance Array moorings not within the sanctuary boundary are equally valuable, not just for prediction purposes, but to our tribal partners. A unique thing about the Olympic Coast National Marine Sanctuary is that nearly the entire sanctuary is within the Usual and Accustomed Fishing Areas of the four coastal treaty tribes in Washington — the Hoh Tribe, Makah Tribe, Quileute Tribe, and the Quinault Indian Nation. The sanctuary and OOI-derived data are particularly valuable to the Quinault Tribe, who use these data to estimate fish runs. They have found, for example, that our oxygen data are a good predictor of the Coho salmon run size in some of the coastal rivers,” Waddell explained.

Olympic Coast Data Applications

Sanctuary data are the foundation of the LiveOcean model, an ongoing project of the University of Washington Coastal Modeling Group that provides short-term (three-day) forecasts of ocean conditions—currents, temperature, salinity and biogeochemical fields such as harmful algal blooms. Sanctuary data also are incorporated in the J-SCOPE model, operated by the Northwest Association of Networked Ocean Observing Systems (NANOOS), for seasonal (six to nine month) forecasts of ocean conditions that are relevant to management decisions for fisheries, protected species, and ecosystem health.

Sanctuary and OOI data also serve as the basis for novel estimates of pre-industrial and near future (2030–2050) ocean acidification conditions on the Olympic Coast led by NOAA Pacific Marine Environmental Laboratory ocean carbon scientists. These estimates are made possible by rich NOAA Ocean Acidification Program-funded coastal observing efforts and inform state and tribal fisheries and water quality management (cf. Alin et al. 2023 in press).

Changing Conditions

“In the 23 years that we’ve been collecting data, we have been documenting changing ocean conditions that are quite alarming,” said Waddell. The 465-page latest Condition Report for the Sanctuary details how ocean conditions along the Olympic Coast continue to change and intensify in response to climate change. The report lays out concerns about the impacts from ocean acidification, warming ocean temperatures, increased stratification, rising sea levels, and declines in dissolved oxygen, in addition to the intermittent occurrences from more intense and frequent marine heatwaves, harmful algal blooms, and coastal storms.

[media-caption path="https://oceanobservatories.org/wp-content/uploads/2023/06/IMG_4898.jpg" link="#"]Oceanographic moorings deployed by Olympic Coast National Marine Sanctuary, such as this mooring near Cape Alava, have been tracking changes in ocean conditions along this remote and rugged coastline for more than two decades.  Credit: Jenny Waddell ©NOAA.[/media-caption]

To help bring this information to the public, the sanctuary has developed a user-friendly and searchable graphic interface that provides easy access to data within the report.  Called the Web Condition Report (WebCR), the interface is designed to connect people with information they are interested in.

[media-caption path="https://oceanobservatories.org/wp-content/uploads/2023/06/OCNMS_O2_plots_5panel_2018-scaled.jpg" link="#"]
This is an example of the type of information available through WebCR. Like animals on land, most marine animal species need oxygen to survive. To obtain oxygen, whales and turtles periodically breathe air at the water’s surface, while most fish species obtain oxygen that is dissolved in seawater. Low oxygen levels can harm marine animals or force them to move to areas with more hospitable conditions. Cape Elizabeth in the south (2006–2017), for example, has gotten progressively worse over time and in recent years is hypoxic 44 percent of the time. Image source: Alin et al., 2023 in prep. Also reprinted from: Office of National Marine Sanctuaries. 2022. Olympic Coast National Marine Sanctuary Condition Report: 2008–2019. U.S. Department of Commerce, National Oceanic and Atmospheric Administration, Office of National Marine Sanctuaries, Silver Spring, MD. 453 pp.[/media-caption]  These 23 years of data now being sorted will help us get a handle on what is really going on in the Pacific Northwest. It’s an important microcosm of what’s happening on a larger scale. Only around 25,000 people live along the Olympic Coast between Neah Bay and Ocean Shores, so the human footprint of this place is minimal. Most of what we’re seeing and what the data are telling us are climate forced issues coming to bear here,” added Waddell. “And having our data in the hands of senior oceanographers who know exactly what to do with it is just so incredibly valuable to understand not only what’s happening at the ocean surface, but within the full water column, which is where most of the impacts of climate change are occurring.”

The Principal Investigator (PI) for this project is College of Earth, Ocean and Atmospheric Science (CEOAS) Oregon State University (OSU) Associate Professor Melanie R. Fewings.  Co-principal Investigators are Craig M. Risien, OSU Senior Faculty Research Assistant II and OOI Cyberinfrastructure Project Manager; Co-Principal Investigator Brandy T. Cervantes, OSU Senior Research Associate.

In addition to the PIs and NOAA’s Waddell, other collaborators include Dr. Simone Alin, NOAA Pacific Marine Environmental Laboratory, Katie Wrubel, Resource Protection Specialist, OCNMS, Joe Schumacker, Marine Resources Scientist, Quinault Indian Nation, Dept. of Fisheries, Tommy Moore, Oceanographer, Northwest Indian Fisheries Commission, Charles Seaton, Senior Oceanographer, Columbia River Inter-Tribal Fish Commission, Kym Jacobson, Research Zoologist, NOAA Northwest Fisheries Science Center, Jennifer Fisher, NOAA Cooperative Institute for Marine Ecosystem and Resources Studies, OSU, and Maria Kavanaugh, Assistant Professor, CEOAS, OSU, and Principal Investigator of the Marine Biodiversity Network.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Read More

Particle Trajectories in an Eastern Boundary Current

Adapted and condensed by OOI from Wong-Ala et al., 2022, doi:/10.1016/j.jmarsys.2022.103757

To study the transport and dispersal of marine organisms during spawning, Wong-Ala* et al. developed and applied a Lagrangian particle tracking (LPT) model to compare and contrast particle drift patterns during the spring transition off the Oregon coast. They studied the Oregon coast as it has distinct upwelling and downwelling regimes and variable shelf width. They contrasted years (2016–18) using Regional Ocean Modeling System (ROMS) with different horizontal spatial resolutions (2 km, 250 m). They found the finer spatial resolution model significantly increased retention along the Oregon coast. Particles in the 250 m ROMS were advected to depth at specific times and locations for each simulated year, coinciding with the location and timing of a strong and shallow alongshore undercurrent that is not present in the 2 km ROMS. Additionally, ageostrophic dynamics close to shore, in the bottom boundary layer, and around headlands not present in the coarser model emerged in the 250 m resolution model. They concluded that the higher horizontal model resolution and bathymetry generated well-resolved mesoscale and submesoscale features (e.g., surface, subsurface, and nearshore jet) that vary annually. These results have implications for modeling the dispersal, growth, and development of coastal organisms with dispersing early life stages.

[media-caption path="/wp-content/uploads/2022/11/Endurance-Highlight.png" link="#"]Figure 1: (Fig 9 from Wong-Ala et al. (2022). Comparison of u-velocity (zonal velocity) data between the 250 m ROMS and an inshore mooring and shelf mooring off the Oregon coast collecting data at seven meters depth. The panel is organized by year: 2016 (row 1), 2017 (row 2), 2018 (row 3), and location of data collection: inshore (column 1) and shelf (column 2). In April 2018, there are no data available from the shelf mooring ADCP.[/media-caption]

The model applied by Wong-Ala assimilates satellite sea surface temperature and along-track altimetry. Model atmospheric forcing is from the NOAA North American Mesoscale Model (NAM). To validate their model, Wong-Ala et al., used OOI Endurance Array time series data from 2016 to 2018 from the Oregon inshore and shelf moorings (CE01ISSM and CE02SHSM). They compared available OOI zonal and meridional velocities, temperature, and salinity to model output of these parameters for the month of April in each year when they ran their model (Figure 1). They found the modeled currents and temperature from the 250 m ROMS model closely follow the observed data from inshore and shelf moorings compared to the 2 km ROMS. The 250 m ROMS modeled currents and observed currents at the inshore mooring are similar for all three years (Figure 1).

They also found that the 250 m ROMS modeled temperature and observed data are similar in 2017 at the inshore and shelf location. In April 2017 and 2018, the modeled temperature from the 250 m ROMS is about 1 °C cooler than the observed temperatures.

_____________________

*Wong-Ala is a PhD student at Oregon State University. She is a Pacific Islander.

Reference:A. T. K. Wong-Ala, Ciannelli, L., Durski, S. M., and Spitz, Y., Particle trajectories in an eastern boundary current using a regional ocean model at two horizontal resolutions, Journal of Marine Systems, vol. 233, p. 103757, 2022. https://doi.org/10.1016/j.jmarsys.2022.103757.

Read More

Two Decades of Mooring and Ship-Based Observations from the Newport Hydrographic Line

[media-caption path="/wp-content/uploads/2022/08/Screen-Shot-2022-08-18-at-3.36.36-PM.png" link="#"](left)Time series of a) temperature b) salinity and c) meridional velocity from the Oregon shelf site.  Time series exist at this site starting in 1997.  The OOI time series begin in summer 2014 for the Regional Cabled Array and spring 2015 for the uncabled Endurance Array.  For clarity, only 2012-2022 are shown.  Prior to OOI, the site was named NH-10.  Adapted from Figures 6, 7, and 8 Risien et al. (2022)Risien et al. (2022), Making Available More Than Two Decades of Mooring and Ship-Based Observations from the Newport Hydrographic Line, OT06-01, presented at Ocean Sciences Meeting 2022, Honolulu, HI (virtual), 4 Mar.[/media-caption]

C.M. Risien, M.R. Fewings, J.L. Fisher, B.T. Cervantes, C.A. Morgan, J.A. Barth, P.M. Kosro, J.O. Peterson, W.T. Peterson, and M.D. Levine

In the Northern California Current System (NCCS), during spring and summer months, equatorward winds drive the upwelling of cold, nutrient-rich, and oxygen-poor waters from depth onto the shelf, fueling a highly productive marine ecosystem that supports valuable commercial fisheries. Oceanographic conditions in the NCCS vary on temporal scales from hours to decades. In contrast, grant-funded research typically consists of shorter-term studies (3-5 years). While such studies resolve intra-annual and perhaps inter-annual variability, they do not capture decadal scale variability that is critical for climate studies.

Risien et al. (2022), present two new decadal-scale data products. The first is ~550 gridded, cross-shelf hydrographic sections of temperature, salinity, potential density, spiciness, and dissolved oxygen from data collected biweekly to monthly from March 1997 to present along the Newport Hydrographic Line (NHL; 44.6°N, 124.1–124.65°W) off Newport, Oregon, USA, mostly by NOAA programs. They also present monthly climatologies derived from these observations.

The second data product is 23 years (1999–2021) of mooring temperature, salinity and velocity data — collected by five programs (OSU-NOPP, GLOBEC, OrCOOS, NANOOS/CMOP, OOI) at NH-10 (44.6°N, 124.3°W), 10 nautical miles west of Newport, Oregon along the NHL — that they stitched together into one coherent, quality-controlled data set (see figure above).

Making available such multi-decadal data sets, which they plan to release via public repositories, is essential to enable scientists to characterize natural and anthropogenically-forced variability; resolve cause-and-effect relationships in Earth’s climate and marine ecosystems at intra-seasonal, seasonal, inter-annual and decadal time scales; and verify climate models. These new gridded and concatenated data products show that long-term ocean observing efforts require multi-generational teams with a wide range of skills and a shared vision that is motivated by science and ocean monitoring needs.

Read More

Applications Open for June Northeast Pacific OOIFB Workshop

Northeast Pacific OOI Community Workshop
June 7, 8, and 9, 2022
Portland, Oregon
The application form is now open!
Application Deadline:  March 20, 2022 

                                                                                                                                                                 The Ocean Observatories Initiative Facility Board (OOIFB) will host a workshop focusing on current and future science that can be addressed using data from OOI’s infrastructure in the Northeast Pacific and other regional observatory arrays. The workshop will be held at the OSU Portland Center in Portland, OR on June 7-9, 2022. This workshop was scheduled to be held in 2020, but was postponed due to the COVID-19 pandemic. The OOIFB is hopeful that in June 2022 members of OOI’s community can safely come together for a productive workshop. A hybrid model with in-person along with options for virtual participation is planned.

The workshop is aimed at researchers who are using or are considering using OOI data; resource managers from national, state, and tribal agencies; and educators at all levels interested in using data from the OOI’s Regional Cabled, Coastal Endurance, and Global Station Papa Arrays.

The workshop will inform the research community of the available data and science opportunities offered by the OOI and other observatory arrays located in the Northeast Pacific. An overview of OOI data products, user interfaces, and system features will be provided along with hands-on demonstrations using data access tools. OOI Program Team members and NSF representatives will be on hand to answer questions and provide information on OOI operations.

The workshop will provide a forum to facilitate science collaborations, identify strategies for engaging future users of OOI, and build cross-network collaborations. Community-building and expanding broader impacts will be discussed. Workshop participants will have the opportunity to provide feedback on their experiences in working with the OOI systems and data.

To apply for the workshop, please complete the on-line application form that is available on the workshop web page. Please indicate how you plan to participate in the workshop (in person or virtual) when completing the form. Travel support is available, but limited. Broad representation from institutional, geographic, and disciplinary groups is desired and will be considered in participant selection. The deadline for applications is March 20, 2022.

Additional details about the workshop and agenda are available here.

 

 

Read More

Rocky Seas Didn’t Deter Endurance 15’s Success

In spite of rocking seas, a generator in need of repair, and a medical delay, the Coastal Endurance Array team successfully completed its mission to turn the array for the 15th time, achieving all of its science objectives.

Weather conditions in the northern Pacific were less-than-ideal for two of the three legs of the two-week expedition.  At one point, winds speeds of 25-30 knots, with accompanying waves of up to 10 feet, caused a weather delay in operations and subsequent alterations in cruise plans.

“While it was comfortable to be aboard the R/V Thomas G. Thompson even in such conditions, sea conditions were borderline for entering or exiting Newport and deploying or recovering most platforms, “explained Chief Scientist Jonathan Fram, who led the 10-member science party. “Fortunately, we had good weather during the first leg of the cruise, which gave us some leeway to address weather-related downtime and other delays during latter legs of the cruise.  We were able to switch the order of some activities, delay some deployments, and ultimately got most everything in and out of the water as planned during our time at sea.”[media-caption path=”https://oceanobservatories.org/wp-content/uploads/2021/09/Screen-Shot-2021-09-28-at-5.20.52-PM.png” link=”#”]When seas were calm, the team was able to deploy moorings like this one. After deployment, they headed back to port with a deck full of recovered equipment.[/media-caption]

The team successfully deployed and recovered six surface moorings, four gliders, and two profilers. They also recovered two additional profilers and an anchor from 2020.  In addition, the team conducted CTD water sampling and also conducted sampling for researchers with instruments on Endurance Array moorings.  The team succeeded in collecting fouling communities growing on buoy panels for researcher Linsey Haram of the Smithsonian Institution and organisms on devices attached to two multi-function nodes for Oklahoma State researcher Ashley Burkett.

While in the roaring sea, the team tested potential instrument replacements and new sampling strategies. They also assessed first-time implementation of technical improvements including a new solar panel frame to prevent sea lions from unplugging the panels, an underwater camera constructed with off-the-shelf replacement parts to ensure longevity and resilience, and a stretch hose from a new manufacturer with a slightly different design than previous versions.

“In spite of having to repeatedly change our plans,” adds Fram, “we were pleased to be able to meet all of the cruise objectives.  The ocean in the Pacific Northwest is too harsh for scientists to go to sea often in fall and winter, so it is important to refresh this array of autonomous platforms that will keep recording and delivering data during rough times.”

Read More

Endurance 15 Happening in Sept

On September 8th, a science team of ten and three students from Oregon State University will depart the dock at Newport, Oregon, aboard the R/V Thomas Thompson for the 15th turn of the Coastal Endurance Array.  The team will recover and deploy seven moorings. Four of the moorings are located on the Washington Shelf, with the remaining three on the Oregon Shelf. It’s a busy expedition. The team also will be recovering four and deploying three Coastal Surface Profilers and recovering three gliders that are low on power. When not turning the arrays, they will be taking CTD (connectivity, temperature, and depth) casts to verify and calibrate instrumentation. Because of the quantity of the equipment to be recovered and deployed, the cruise will consist of three legs.

“As we head to sea for the fifteenth time to turn this array, it’s remarkable to consider that the Endurance Array has been generating data for researchers, teachers, and others interested in the ocean, every day, 24/7 for the past seven years, said Jonathan Fram, who is the chief scientist for Endurance 15.  “Our data has helped identify everything from warm blobs to low-oxygen events, to even the impact of forest fire smoke miles from shore.”

[media-caption path=”https://oceanobservatories.org/wp-content/uploads/2021/09/Screen-Shot-2021-09-03-at-3.17.24-PM.png” link=”#”]Members of the Coastal Endurance Array 15 team prepare moorings for moving to pier for loading onto the R/V Thomas Thompson. Credit: Jon Fram, OSU.[/media-caption]

To help advance science, the Endurance 15 team also will be sampling for researchers with instruments on the Endurance Array moorings.  The team will collect fouling communities growing on panels attached to its deployed buoys for researcher Linsey Haram of the Smithsonian Institution. They will also collect settling organisms on devices attached to two multi-function nodes for Oklahoma State researcher Ashley Burkett.

The team also will be testing potential instrument replacements and new sampling strategies for coastal moorings. Additionally, they will be assessing technical improvements to the moorings and instrumentation that range from a new solar panel frame design to prevent sea lions from unplugging the panels to improvements to cameras deployed on the moorings with off-the-shelf replacement parts to ensure longevity and resilience.

Check back here often during September as the Endurance Array 15 team shares reports and photographs of their expedition.

Read More

Testing of New Glider Models Underway

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.

 

Read More

Oregon Sea Grant Spotlights Partner OOI

In its August 2021 newsletter, Oregon Sea Grant highlights the work of OOI’s Endurance Array Team at Oregon State University. Sea Grant Scholar Charlotte Klein interviewed the Endurance Array Principal Investigator Ed Dever, who describes some of challenges in keeping arrays operational in a challenging offshore environment.

The article can be found here, on page four.

Read More

Jupyter Notebook Produces Quality Flags for pH Data

OOI uses the SAMI2-pH sensor from Sunburst Sensors, LLC to measure seawater pH throughout the different arrays.  Assessing the data quality from this instrument is an involved process as there are multiple parameters produced by the instrument that are then used to calculate the seawater pH.  These measurements are subject to different sources of error, and those errors can propagate through the calculations to create an erroneous seawater pH value. Based upon the vendor documentation and MATLAB code Sunburst provides to convert the raw measurements, OOI data team members have created a set of rules from those different measurements to flag the pH data as either pass, suspect or fail.

The resulting flags can be used to remove failed data from further analysis. They can also be used to help generate annotations for further Human in the Loop (HITL) QC checks of the data to help refine quality metrics for the data. OOI team member, Chris Wingard (OSU), has written up the QC process as a Python Jupyter notebook. This notebook and other example notebooks are freely available to the scientific community via the OOI GitHub site (within the OOI Data Team Python toolbox accessed from https://oceanobservatories.org/community-tools/ ).

In this notebook, Wingard shows how the quality rules can be used to remove bad pH data from a time series, and how they can be used to then create annotations. The impact of using these flags is shown with a set of before and after plots of the seawater pH as a function of temperature.  The quality controlled data can then be used to estimate the seasonal cycle of pH to set climatological quality control flags.

Here an example is shown using data from a pH sensor on the Oregon Inshore Surface Mooring (CE01ISSM) near surface instrument frame (NSIF), deployed at 7 m depth (site depth is 25 m).

[media-caption path="https://oceanobservatories.org/wp-content/uploads/2021/07/EA-Highlight.png" link="#"]Figure 25: pH data from the Oregon Inshore Surface Mooring (CE01ISSM) near surface instrument frame (NSIF).  Good data are shown in black, failed data in red.  Note that simple range tests on the final calculated pH are often not enough to distinguish good from failed data.  The automated QC processing examines intermediate measurements and fails data if intermediate measurements are outside acceptable ranges and propagated to final measurements.[/media-caption] [media-caption path="https://oceanobservatories.org/wp-content/uploads/2021/07/EA-highlight-2.png" link="#"]Figure 26: Good data together with annual cycles (red) constructed with available good data from initial deployment through 2021.  Data which falls outside three standard deviations of the climatology is flagged as suspect.  The climatological tests are used to flag suspect data.  Simple range tests for suspect (cyan) and failed (magenta) data are also shown.  The annual cycle at this site is strongly influenced by annual summer upwelling and winter storms and river plumes.  The summer decrease in pH is consistent with cold, relatively acidic upwelled water high in CO2 (see e.g., Evans et al., 2011)[/media-caption]

 


Evans, W., B. Hales, and P. G. Strutton (2011), Seasonal cycle of surface ocean pCO2on the Oregon shelf,J. Geophys. Res., 116, C05012, doi:10.1029/2010JC006625.

Read More