Setting the PACE in Ocean Observations: NOAA Incorporating New NASA Science Mission Data into Operational Ocean Color Observations (2024)

NOAA offers a comprehensive set of ocean color products that integrate information from NOAA, NASA, and international partner satellites. These products are used to assess water quality and monitor potentially harmful algal blooms in order to protect public health. On February 8, 2024, NASA launched the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission, which is another new resource to help us better understand our oceans and climate.

PACE measures the distribution of phytoplankton, tiny plants and algae that sustain aquatic food webs, and also studies clouds, aerosols, and the relationship between the atmosphere and ocean. It has already begun sharing images and information that are providing insights into ocean health, air quality, and the effects of climate change.

Information collected via PACE is freely available for anyone to use, including the public. NOAA and NASA are collaborating with a goal to develop products from PACE that are tailored for NOAA operational applications and to put existing products on the pathway to stakeholders. Applications include the enhancement and creation of new indicators of ecosystem status, incorporation into harmful algal bloom forecasts and ocean management tools, and the verification of the newest climate, ocean, and ecosystem models. Together, NOAA and NASA are striving to deliver the most accurate ocean color data for the complex waters of the coastal seas. By engaging a global community of scientists, agencies, and institutions, NOAA and NASA look forward to remarkable advances from this instrument.

“PACE promises to deliver unprecedented new insights about our home planet on daily, global scales,” said PACE Project Scientist Jeremy Werdell, PhD. “Its data inform on phenomena that range from those that impact our everyday lives to those that affect and are affected by generational-scale climate change. I am energized by the community’s enthusiasm for this mission and eagerly await seeing how our partners use PACE data.”

This work will not only enhance current capabilities, but also prepare for future efforts, such as NOAA’s Ocean Color (OCX) instrument onboard its next-generation Geostationary Extended Observations (GeoXO) satellite series and NASA’s Earth Venture project, the Geosynchronous Littoral Imaging and Monitoring Radiometer (GLIMR), which will be the Nation’s first geostationary ocean color platform.

PACE aims to provide a combination of global atmospheric and oceanic observations to benefit society in the areas of water resources, disaster impacts, ecological forecasting, air quality, and human health. It does this by utilizing multi-angle polarimeters as well as the Nation’s first global hyperspectral Ocean Color Instrument (OCI).

What is Ocean Color?

Imagine looking at bodies of water from space and being able to see the tiny and often microscopic organisms such as plants and algae living in it, as well as mineral particles and dissolved organic matter. The interaction of sunlight with substances within the water influences the color of it, which varies based on how these materials absorb and scatter photons of different wavelengths (i.e. colors) of light. By studying these colors, scientists can learn more about what's happening in oceans and lakes around the world.

For example, productive waters, where phytoplankton are abundant, appear green, and less productive waters typically appear blue. This information aids in the enhanced tracking and understanding of the marine environment and ecosystem, as well as the detection, monitoring, and prediction of short-term biological phenomena such as harmful algal blooms (HABs). It also allows us to make more informed decisions about marine resource management and provides vital information for fisheries, fishing communities, and coastal communities.

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Ocean Color Sensors

Historically, multispectral sensors could only see a few colors—up to 10 or so. But now, with advanced hyperspectral instruments onboard PACE, we can now see hundreds.

PACE covers ultraviolet, visible, near infrared, and several shortwave infrared wavelengths, giving us an unprecedented view of the ocean without the gaps we had before.

How Will NOAA Use PACE Data?

NOAA has three main focus areas that PACE is expected to impact:

Ocean Biology Indicators

Since our Earth System is very complex, environmental indicators provide a more general way to track the state of our ocean and coasts. These relatively simple measures tell us what is happening in our natural world.

In ocean biology, there are three main indicators of interest: phytoplankton concentration, composition, and productivity. Phytoplankton is a term for the diverse groups of microscopic single-celled aquatic organisms that can convert sunlight into food via photosynthesis. Phytoplankton are also known as microscopic marine algae, or microalgae.

Phytoplankton make up the base of most marine food webs, and are responsible for nearly all marine primary production, or the rate of photosynthesis and uptake of dissolved nutrients such as nitrates and phosphates to produce more plant matter or biomass. They also generate almost half of the Earth’s oxygen and play an important role in capturing and storing atmospheric carbon dioxide via a process called carbon cycling and sequestration.

In a balanced ecosystem, phytoplankton provide food for a wide range of sea creatures including krill, snails, jellyfish, and small fish. When too many nutrients are available, phytoplankton may grow out of control and form harmful algal blooms (HABs). These blooms can produce extremely toxic compounds that have harmful effects on fish, shellfish, mammals, birds, and even people.

Phytoplankton concentration measurements provide, among other things, an understanding of the timing and intensity of blooms. Data on the reflectance of certain wavelengths, detected by satellite instruments, contribute to an estimate of chlorophyll a—the predominant photosynthetic pigment found in green plants and algae. Insight into ecosystem stability, marine biogeochemistry, and even potential fishery stock production may be achieved through a measurement of phytoplankton diversity, or types of algae that exist in a given area.

NOAA's State of the Ecosystem reports from the Northeast Fisheries Science Center compile various indicators on the current status of Northeast Shelf marine ecosystems to provide a comprehensive view of coastal seas and aid in fishery management.

Hyperspectral data from PACE will help improve our understanding of these indicators. Not only will the data show us where phytoplankton are, but now it will be able to identify their functional type and size, which, in some cases, will help us better identify which species are present. This information is crucial for helping us to make informed decisions to support aquaculture activities and tracking algal blooms in coastal waters, which is a more optically complex environment due to colored dissolved organic matter and sediments that interfere with the color signatures from phytoplankton.

Forecasting Tools

Forecasting tools, which enable us to conduct dynamic ocean management, help us predict various types of aquatic phenomena.

“We rely on satellite data to both understand and predict how species are responding to changing oceans,” said Elliott Hazen, Ph.D., an ecologist at NOAA’s Southwest Fisheries Science Center.

For example, harmful algal bloom forecasting utilizes satellite data to detect and predict spikes in chlorophyll a concentration. Data from PACE will help us detect and predict whether algae is benign or harmful.

There are many other types of forecasts as well. For example, some on the West Coast predict turtle and blue whale locations based on satellite tracking as well as information on their surrounding environment to help shipping and fishing industries avoid them. Another example is a tool called EcoCast, which is used to minimize bycatch in fishing nets, enhancing both environmental sustainability and economic efficiency.

The advanced capabilities of instruments like PACE satellite data will also improve the accuracy and performance of these forecasts.

Kari St.Laurent, Ph.D., chief of NOAA’s Harmful Algal Bloom Forecasting Branch, explained how she and her team are excited to see how PACE data can enhance our ability to forecast harmful algal blooms. “By using satellite data to identify different types of phytoplankton, we might be better able to predict if a bloom could produce toxins in real-time and in the future. Although more research is needed, this could lead to more accurate and useful HAB forecasts for managers and the public.”

Model Verification

Model verification is crucial for understanding how marine ecosystems respond to change. To study this, NOAA’s National Marine Fisheries Service is developing several ecosystem models coupled with climate models which require satellite data to ensure accuracy. With the environment changing rapidly, model verification is essential to ensure reliability. PACE will contribute to verifying these models under NOAA's Climate, Ecosystems, and Fisheries Initiative (CEFI).

One challenge lies in accurately estimating chlorophyll concentration in optically complex coastal waters, unlike the clearer waters of the open ocean. These coastal areas, rich in organic material and particulates, make it difficult for satellites to distinguish chlorophyll from other substances. PACE's hyperspectral capabilities provide more detailed data to differentiate between different components in these complex waters, offering a more effective tool for research and monitoring.

GeoXO and Beyond

Most ocean color data is collected via polar-orbiting satellites, which include not only PACE, but NOAA’s Joint Polar Satellite System (JPSS) satellites as well as others from around the world. Additionally, the Korean Meteorological Administration (KMA) maintains the only operational geostationary ocean color instrument in orbit (GOCI-II) onboard the GEO-Kompsat-2B (Chollian-2B) satellite, which monitors coastal waters around the Korean Peninsula. However, its imager is multispectral rather than hyperspectral, and thus only sees a limited number of colors.

PACE is a pathfinder mission, or first of its kind, using a hyperspectral imager to study ocean color on daily, global scales. Moving forward, NOAA plans to learn from NASA’s achievement and commit to integrating its data into essential products as well as launching subsequent operational satellites with comparable technology to ensure continuous data collection in the future.

Having ocean color instruments onboard NOAA’s geostationary satellites will be a game changer for us in the Western Hemisphere. Polar-orbiting satellites only pass over certain areas once or twice a day, and might miss things like harmful algal blooms if they're hidden under clouds. However, geostationary satellites orbit at the same speed that the planet rotates, remaining over the same area. This allows them to constantly monitor that specific area, and watch for when the clouds move. The OCX instrument will analyze ocean data within the U.S.Exclusive Economic Zone (EEZ) and Great Lakes at least every three hours.

OCX will be a hyperspectral instrument that will analyze a wide spectrum of light from ultraviolet to near-infrared. It will also provide higher resolution data than what is currently available on today’s satellites. High-resolution ocean color imagery will improve observations of water clarity and chlorophyll concentration as well as provide better detection of harmful algal blooms and coastal pollutants. Finer resolution will also allow scientists to better monitor water quality within smaller bodies of water and along the coast where urbanization and high nutrient runoff have an increasingly negative impact on the livelihoods of local communities.

Frequent, high-resolution ocean color imagery will help NOAA provide more accurate and timely forecasts and scientific guidance to federal, state, and local agencies. OCX observations will support ecological forecasters, marine resource managers, fisheries, health departments,water treatment managers, and the commerce, recreation, and tourism industries. NOAA expects that GeoXO will begin operating in the early 2030s.

GLIMR

Another project currently in development that will utilize hyperspectral imagery onboard a geostationary platform is the Geosynchronous Littoral Imaging and Monitoring Radiometer (GLIMR), a space-based instrument that will help scientists observe and monitor ocean biology, chemistry, and ecology throughout the Gulf of Mexico, the southeastern U.S. coastline and Amazon River plume that stretches to the Atlantic Ocean.

The project was awarded to a team at the University of New Hampshire, Durham under the NASA Earth Venture Program. GLIMR will provide federal, state, and local agencies with vital information on coastal hazards (such as oil spills, harmful algal blooms, post-storm assessment, and water quality) for improved response, containment, and public advisories both at sea and along the coast. It will collect images hourly and represents an opportunity to use advances made with the hyperspectral instrument on PACE and explore new observations of how things change during the day. Furthermore, GLIMR will provide an important testbed to refine our approaches on the calibration of geostationary ocean observing satellites, which is a critical step prior to GeoXO’s launch.

As these initiatives progress, the realm of ocean observation stands poised for transformative growth, ushering in a new era of scientific discovery and environmental stewardship. Each advancement moves us closer to a deeper understanding of Earth's ocean and a more sustainable future for generations to come.