Jump to content
Join the Alien Search, login or register FREE on Aliens and Space Forum
Members Can Post Anonymously On This Site

By Air and by Sea: Validating NASA’s PACE Ocean Color Instrument

NASA

By NASA
in NASA

 Share

Recommended Posts

  • Publishers
NASA Mentor

NASA

Posted
  • Publishers
Posted

6 min read

Preparations for Next Moonwalk Simulations Underway (and Underwater)

A woman in a blue facemask sits in an airplane, typing on a laptop with a large screen in front of her. The scene is lit by a round window in the middle of the frame.
NASA Ames research scientist Kristina Pistone monitors instrument data while onboard the Twin Otter aircraft, flying over Monterey Bay during the October 2024 deployment of the AirSHARP campaign.
NASA/Samuel Leblanc

In autumn 2024, California’s Monterey Bay experienced an outsized phytoplankton bloom that attracted fish, dolphins, whales, seabirds, and – for a few weeks in October – scientists. A team from NASA’s Ames Research Center in Silicon Valley, with partners at the University of California, Santa Cruz (UCSC), and the Naval Postgraduate School, spent two weeks on the California coast gathering data on the atmosphere and the ocean to verify what satellites see from above. In spring 2025, the team returned to gather data under different environmental conditions.

Scientists call this process validation.

Setting up the Campaign

The PACE mission, which stands for Plankton, Aerosol, Cloud, ocean Ecosystem, was launched in February  2024 and designed to transform our understanding of ocean and atmospheric environments. Specifically, the satellite will give scientists a finely detailed look at life near the ocean surface and the composition and abundance of aerosol particles in the atmosphere.

Whenever NASA launches a new satellite, it sends validation science teams around the world to confirm that the data from instruments in space match what traditional instruments can see at the surface. AirSHARP (Airborne aSsessment of Hyperspectral Aerosol optical depth and water-leaving Reflectance Product Performance for PACE) is one of these teams, specifically deployed to validate products from the satellite’s Ocean Color Instrument (OCI).

The OCI spectrometer works by measuring reflected sunlight. As sunlight bounces off of the ocean’s surface, it creates specific shades of color that researchers use to determine what is in the water column below. To validate the OCI data, research teams need to confirm that measurements directly at the surface match those from the satellite. They also need to understand how the atmosphere is changing the color of the ocean as the reflected light is traveling back to the satellite.

In October 2024 and May 2025, the AirSHARP team ran simultaneous airborne and seaborne campaigns. Going into the field during different seasons allows the team to collect data under different environmental conditions, validating as much of the instrument’s range as possible.

Over 13 days of flights on a Twin Otter aircraft, the NASA-led team used instruments called 4STAR-B (Spectrometer for sky-scanning sun Tracking Atmospheric Research B), and the C-AIR (Coastal Airborne In-situ Radiometer) to gather data from the air. At the same time, partners from UCSC used a host of matching instruments onboard the research vessel R/V Shana Rae to gather data from the water’s surface.

Ocean Color and Water Leaving Reflectance

The Ocean Color Instrument measures something called water leaving reflectance, which provides information on the microscopic composition of the water column, including water molecules, phytoplankton, and particulates like sand, inorganic materials, and even bubbles. Ocean color varies based on how these materials absorb and scatter sunlight. This is especially useful for determining the abundance and types of phytoplankton.

Four panels of image look at the ocean from a plane window. The water is various shades of teal, deep blue, and red.
Photographs taken out the window of the Twin Otter aircraft during the October 2024 AirSHARP deployment showcase the variation in ocean color, which indicates different molecular composition of the water column beneath. The red color in several of these photos is due to a phytoplankton bloom – in this case a growth of red algae.
NASA/Samuel Leblanc

The AirSHARP team used radiometers with matching technology – C-AIR from the air and C-OPS (Compact Optical Profiling System) from the water – to gather water leaving reflectance data.

“The C-AIR instrument is modified from an instrument that goes on research vessels and takes measurements of the water’s surface from very close range,” said NASA Ames research scientist Samuel LeBlanc. “The issue there is that you’re very local to one area at a time. What our team has done successfully is put it on an aircraft, which enables us to span the entire Monterey Bay.”

The larger PACE validation team will compare OCI measurements with observations made by the sensors much closer to the ocean to ensure that they match, and make adjustments when they don’t. 

Aerosol Interference

One factor that can impact OCI data is the presence of manmade and natural aerosols, which interact with sunlight as it moves through the atmosphere. An aerosol refers to any solid or liquid suspended in the air, such as smoke from fires, salt from sea spray, particulates from fossil fuel emissions, desert dust, and pollen.

Imagine a 420 mile-long tube, with the PACE satellite at one end and the ocean at the other. Everything inside the tube is what scientists refer to as the atmospheric column, and it is full of tiny particulates that interact with sunlight. Scientists quantify this aerosol interaction with a measurement called aerosol optical depth.

“During AirSHARP, we were essentially measuring, at different wavelengths, how light is changed by the particles present in the atmosphere,” said NASA Ames research scientist Kristina Pistone. “The aerosol optical depth is a measure of light extinction, or how much light is either scattered away or absorbed by aerosol particulates.” 

The team measured aerosol optical depth using the 4STAR-B spectrometer, which was engineered at NASA Ames and  enables scientists to identify which aerosols are present and how they interact with sunlight.

Twin Otter Aircraft

A small white plane with orange details sits on the tarmac with a silver hangar and blue sky behind it. A woman with blonde hair walks towards it.
AirSHARP principal investigator Liane Guild walks towards a Twin Otter aircraft owned and operated by the Naval Postgraduate School. The aircraft’s ability to perform complex, low-altitude flights made it the ideal platform to fly multiple instruments over Monterey Bay during the AirSHARP campaign.
NASA/Samuel Leblanc

Flying these instruments required use of a Twin Otter plane, operated by the Naval Postgraduate School (NPS). The Twin Otter is unique for its ability to perform extremely low-altitude flights, making passes down to 100 feet above the water in clear conditions.

“It’s an intense way to fly. At that low height, the pilots continually watch for and avoid birds, tall ships, and even wildlife like breaching whales,” said Anthony Bucholtz, director of the Airborne Research Facility at NPS.

With the phytoplankton bloom attracting so much wildlife in a bay already full of ships, this is no small feat. “The pilots keep a close eye on the radar, and fly by hand,” Bucholtz said, “all while following careful flight plans crisscrossing Monterey Bay and performing tight spirals over the Research Vessel Shana Rae.”

Campaign Data

Data gathered from the 2024 phase of this campaign is available on two data archive systems. Data from the 4STAR instrument is available in the PACE data archive  and data from C-AIR is housed in the SeaBASS data archive.

Other data from the NASA PACE Validation Science Team is available through the PACE website: https://pace.oceansciences.org/pvstdoi.htm#

Samuel LeBlanc and Kristina Pistone are funded via the Bay Area Environmental Research Institute (BAERI), which  is a scientist-founded nonprofit focused on supporting Earth and space sciences.

About the Author

Milan Loiacono

Milan Loiacono

Science Communication Specialist

Milan Loiacono is a science communication specialist for the Earth Science Division at NASA Ames Research Center.

Share

Details

Last Updated
Jun 26, 2025

Related Terms

Explore More

toi_1338-optimized.gif
2 min read

NASA Citizen Scientists Find New Eclipsing Binary Stars

When two stars orbit one another in such a way that one blocks the other’s…

Article 32 minutes ago
56343210-8419-4a4c-a633-3b840b1687ccOrig
4 min read

NASA-Assisted Scientists Get Bird’s-Eye View of Population Status

NASA satellite data and citizen science observations combine for new findings on bird populations.

Article 22 hours ago
OWWL_Logo_whitebg.png
2 min read

Live or Fly a Plane in California? Help NASA Measure Ozone Pollution!

Ozone high in the stratosphere protects us from the Sun’s ultraviolet light. But ozone near…

Article 2 days ago

View the full article

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
 Share
Go to topic listing

  • Similar Topics

    • Space Force
      Additional Department of the Air Force guidance on implementing policy on prioritizing military excellence and readiness: General guidelines for involuntary separation
      By Space Force
      The Department of the Air Force released additional guidance for implementation of Executive Order 14183, "Prioritizing Military Excellence and Readiness,"
      View the full article
    • NASA
      NASA Tests Research Aircraft to Improve Air Taxi Flight Controls
      By NASA
      4 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      The Research Aircraft for electric Vertical takeoff and landing Enabling techNologies Subscale Wind Tunnel and Flight Test undergoes a free flight test on the City Environment Range Testing for Autonomous Integrated Navigation range at NASA’s Langley Research Center in Hampton, Virginia on April 22, 2025.NASA/Rob Lorkiewicz Flying the friendly skies may one day include time-saving trips in air taxis to get from point A to point B – and NASA researchers are currently working to make that future a reality.
      They are using wind tunnel and flight tests to gather data on an electric Vertical takeoff and landing (eVTOL) scaled-down small aircraft that resembles an air taxi that aircraft manufacturers can use for their own designs.
      As air taxis take to the skies, engineers need real-world data on air taxi designs to better understand flight dynamics and design better flight control systems. These systems help stabilize and guide the motion of an aircraft while in flight, making sure it flies safely in various conditions.
      Currently, most companies developing air taxis keep the information about how their aircraft behaves internal, so NASA is using this small aircraft to produce public, non-proprietary data available to all.
      “NASA’s ability to perform high-risk flight research for increasingly automated and autonomous aircraft is really important,” said Siena Whiteside, who leads the Research Aircraft for eVTOL Enabling techNologies (RAVEN) project. “As we investigate these types of vehicles, we need to be able push the aircraft to its limits and understand what happens when an unforeseen event occurs…”
      For example, Whiteside said, “…when a motor stops working. NASA is willing to take that risk and publish the data so that everyone can benefit from it.”
      Researchers Jody Miller, left, and Brayden Chamberlain, right, stand by a crane that is used for tethered flight testing of the Research Aircraft for electric Vertical takeoff and landing Enabling techNologies Subscale Wind Tunnel and Flight Test at NASA’s Langley Research Center in Hampton, Virginia on Oct. 18, 2024.NASA/Ben Simmons Testing Air Taxi Tech
      By using a smaller version of a full-sized aircraft called the RAVEN Subscale Wind Tunnel and Flight Test (RAVEN SWFT) vehicle, NASA is able to conduct its tests in a fast and cost-effective manner.
      The small aircraft weighs 38 pounds with a wingspan of six feet and has 24 independently moving components.
      Each component, called a “control effector,” can move during flight to change the aircraft’s motion – making it an ideal aircraft for advanced flight controls and autonomous flight research.
      The testing is ongoing at NASA’s Langley Research Center in Hampton, Virginia.
      Researchers first used the center’s 12-Foot Low-Speed Tunnel in 2024 and have since moved on to flight testing the small aircraft, piloting it remotely from the ground. During initial flight tests, the aircraft flew while tied to a tether. Now, the team performs free flights.
      Lessons learned from the aircraft’s behavior in the wind tunnel helped to reduce risks during flight tests. In the wind tunnel, researchers performed tests that closely mirror the motion of real flight.
      While the scale aircraft was in motion, researchers collected information about its flight characteristics, greatly accelerating the time from design to flight.
      The team also could refine the aircraft’s computer control code in real time and upload software changes to it in under 5 minutes, saving them weeks and increasing the amount of data collected.
      Researchers Ben Simmons, left, and Greg Howland, right, upload software changes in real time to the Research Aircraft for electric Vertical takeoff and landing Enabling techNologies Subscale Wind Tunnel and Flight Test at NASA’s Langley Research Center in Hampton, Virginia on Aug. 8, 2024, during testing in the 12-Foot Low-Speed Tunnel.NASA/David C. Bowman Partners in Research
      NASA developed the custom flight controls software for RAVEN SWFT using tools from the company MathWorks.
      NASA and MathWorks are partners under a Space Act Agreement to accelerate the design and testing of flight control approaches on RAVEN SWFT, which can apply to future novel aircraft.
      The work has allowed NASA’s researchers to develop new methods to reduce the time for an aircraft to achieve its first flight and become a finished product.
      RAVEN SWFT serves as a steppingstone to support the development of a potential larger, 1,000 pound-class RAVEN aircraft that will resemble an air taxi.
      This larger RAVEN aircraft is being designed in collaboration with Georgia Institute of Technology and also would serve as an acoustical research tool, helping engineers understand the noise air taxi-like aircraft create.
      The larger aircraft would allow NASA to continue to collect data and share it openly.  
      By performing flight research and making its data publicly available, NASA aims to advance U.S. leadership in technology development for safe, quiet, and affordable advanced air mobility operations.
      Watch this Air Taxi Tests Video
      Facebook logo @NASA@NASAaero@NASA_es @NASA@NASAaero@NASA_es Instagram logo @NASA@NASAaero@NASA_es Linkedin logo @NASA Explore More
      4 min read NASA Seeks Moon and Mars Innovations Through University Challenge
      Article 14 hours ago 3 min read NASA Uses Wind Tunnel to Test Advanced Air Mobility Aircraft Wing
      Article 7 days ago 3 min read Three NASA Langley Employees Win Prestigious Silver Snoopy Awards 
      Article 7 days ago Keep Exploring Discover More Topics From NASA
      Missions
      Artemis
      Aeronautics STEM
      Explore NASA’s History
      Share
      Details
      Last Updated Aug 13, 2025 EditorJim BankeContactDiana Fitzgeralddiana.r.fitzgerald@nasa.govLocationNASA Langley Research Center Related Terms
      Aeronautics Advanced Air Mobility Aeronautics Research Mission Directorate Drones & You Flight Demos Capabilities Integrated Aviation Systems Program Langley Research Center NASA Aircraft Transformational Tools Technologies Transformative Aeronautics Concepts Program View the full article
    • European Space Agency
      FLEX instrument meets its satellite
      By European Space Agency
      Image: The development of ESA’s Earth Explorer FLEX mission has recently passed a significant milestone: the mission’s all-important instrument has been joined to its satellite platform. View the full article
    • NASA
      NASA’s SpaceX Crew-10 Splashes Down in Pacific Ocean
      By NASA
      NASA/Keegan Barber The members of NASA’s SpaceX Crew-10 mission – Roscosmos cosmonaut Kirill Peskov, left, NASA astronauts Nichole Ayers and Anne McClain, and JAXA (Japan Aerospace Exploration Agency) astronaut Takuya Onishi – are all smiles after having landed in the Pacific Ocean off the coast of San Diego, Calif., Saturday, Aug. 9, 2025. The crew spent seven months aboard the International Space Station.
      Along the way, Crew-10 contributed hundreds of hours to scientific research, maintenance activities, and technology demonstrations. McClain, Ayers, and Onishi completed investigations on plant and microalgae growth, examined how space radiation affects DNA sequences in plants, observed how microgravity changes human eye structure and cells in the body, and more. The research conducted aboard the orbiting laboratory advances scientific knowledge and demonstrates new technologies that enable us to prepare for human exploration of the Moon and Mars.
      McClain and Ayers also completed a spacewalk on May 1. It was the third spacewalk for McClain and the first for Ayers.
      See more photos from Crew-10 Splashdown.
      Image credit: NASA/Keegan Barber
      View the full article
    • NASA
      NASA Uses Wind Tunnel to Test Advanced Air Mobility Aircraft Wing
      By NASA
      3 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      NASA employees Broderic J. Gonzalez, left, and David W. Shank install pieces of a 7-foot wing model in preparation for testing in the 14-by-22-Foot Subsonic Wind Tunnel at NASA’s Langley Research Center in Hampton, Virginia, in May 2025. The lessons learned will be shared with the public to support advanced air mobility aircraft development. NASA/Mark Knopp The advanced air mobility industry is currently working to produce novel aircraft ranging from air taxis to autonomous cargo drones, and all of those designs will require extensive testing – which is why NASA is working to give them a head-start by studying a special kind of model wing. The wing is a scale model of a design used in a type of aircraft called a “tiltwing,” which can swing its wing and rotors from vertical to horizontal. This allows the aircraft to take off, hover, and land like a helicopter, or fly like a fixed-wing airplane. This design enables versatility in a range of operating environments.
      Several companies are working on tiltwings, but NASA’s research into the scale wing will also impact nearly all types of advanced air mobility aircraft designs.
      “NASA research supporting advanced air mobility demonstrates the agency’s commitment to supporting this rapidly growing industry,” said Brandon Litherland, principal investigator for the test at NASA’s Langley Research Center in Hampton, Virginia. “Tool improvements in these areas will greatly improve our ability to accurately predict the performance of new advanced air mobility aircraft, which supports the adoption of promising designs. Gaining confidence through testing ensures we can identify safe operating conditions for these new aircraft.”
      NASA researcher Norman W. Schaeffler adjusts a propellor, which is part of a 7-foot wing model that was recently tested at NASA’s Langley Research Center in Hampton, Virginia. In May and June, NASA researchers tested the wing in the 14-by-22-Foot Subsonic Wind Tunnel to collect data on critical propeller-wing interactions. The lessons learned will be shared with the public to support advanced air mobility aircraft development.NASA/Mark Knopp In May and June, NASA tested a 7-foot wing model with multiple propellers in the 14-by-22-Foot Subsonic Wind Tunnel at Langley. The model is a “semispan,” or the right half of a complete wing. Understanding how multiple propellers and the wing interact under various speeds and conditions provides valuable insight for the advanced air mobility industry. This information supports improved aircraft designs and enhances the analysis tools used to assess the safety of future designs.
      This work is managed by the Revolutionary Vertical Lift Technology project under NASA’s Advanced Air Vehicles Program in support of NASA’s Advanced Air Mobility mission, which seeks to deliver data to guide the industry’s development of electric air taxis and drones.
      “This tiltwing test provides a unique database to validate the next generation of design tools for use by the broader advanced air mobility community,” said Norm Schaeffler, the test director, based at Langley. “Having design tools validated for a broad range of aircraft will accelerate future design cycles and enable informed decisions about aerodynamic and acoustic performance.”
      In May and June, NASA researchers tested a 7-foot wing model in the 14-by-22-Foot Subsonic Wind Tunnel at NASA’s Langley Research Center in Hampton, Virginia. The team collected data on critical propeller-wing interactions over the course of several weeks.NASA/Mark Knopp The wing is outfitted with over 700 sensors designed to measure pressure distribution, along with several other types of tools to help researchers collect data from the wing and propeller interactions. The wing is mounted on special sensors to measure the forces applied to the model. Sensors in each motor-propeller hub to measure the forces acting on the components independently.
      The model was mounted on a turntable inside the wind tunnel, so the team could collect data at different wing tilt angles, flap positions, and rotation rates. The team also varied the tunnel wind speed and adjusted the relative positions of the propellers.  
      Researchers collected data relevant to cruise, hover, and transition conditions for advanced air mobility aircraft. Once they analyze this data, the information will be released to industry on NASA’s website.
      Share
      Details
      Last Updated Aug 07, 2025 EditorDede DiniusContactTeresa Whitingteresa.whiting@nasa.gov Related Terms
      Armstrong Flight Research Center Advanced Air Mobility Advanced Air Vehicles Program Aeronautics Drones & You Langley Research Center Revolutionary Vertical Lift Technology Explore More
      3 min read Three NASA Langley Employees Win Prestigious Silver Snoopy Awards 
      Article 3 hours ago 3 min read NASA Drop Test Supports Safer Air Taxi Design and Certification
      Article 1 week ago 3 min read NASA Rehearses How to Measure X-59’s Noise Levels
      Article 2 weeks ago Keep Exploring Discover More Topics From NASA
      Armstrong Flight Research Center
      Humans in Space
      Climate Change
      Solar System
      View the full article

  • Check out these Videos

×
×
  • Create New...