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NASA’s PACE Mission Reveals a Year of Terrestrial Data on Plant Health

✇NASA
By:Erica McNamee
5 June 2025 at 10:15

4 min read

Preparations for Next Moonwalk Simulations Underway (and Underwater)

A lot can change in a year for Earth’s forests and vegetation, as springtime and rainy seasons can bring new growth, while cooling temperatures and dry weather can bring a dieback of those green colors. And now, a novel type of NASA visualization illustrates those changes in a full complement of colors as seen from space.

Researchers have now gathered a complete year of PACE data to tell a story about the health of land vegetation by detecting slight variations in leaf colors. Previous missions allowed scientists to observe broad changes in chlorophyll, the pigment that gives plants their green color and also allows them to perform photosynthesis. But PACE now allows scientists to see three different pigments in vegetation: chlorophyll, anthocyanins, and carotenoids. The combination of these three pigments helps scientists pinpoint even more information about plant health. Credit: NASA’s Goddard Space Flight Center

NASA’s Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) satellite is designed to view Earth’s microscopic ocean plants in a new lens, but researchers have proved its hyperspectral use over land, as well.

Previous missions measured broad changes in chlorophyll, the pigment that gives plants their green color and also allows them to perform photosynthesis. Now, for the first time, PACE measurements have allowed NASA scientists and visualizers to show a complete year of global vegetation data using three pigments: chlorophyll, anthocyanins, and carotenoids. That multicolor imagery tells a clearer story about the health of land vegetation by detecting the smallest of variations in leaf colors.

“Earth is amazing. It’s humbling, being able to see life pulsing in colors across the whole globe,” said Morgaine McKibben, PACE applications lead at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It’s like the overview effect that astronauts describe when they look down at Earth, except we are looking through our technology and data.”

A visualization of North America where the land is overlayed with colors representing data. The east side of the land swirls with blues, greens, and pinks, while the west side is primarily gray.
Anthocyanins, carotenoids, and chlorophyll data light up North America, highlighting vegetation and its health. For the full visualization, visit: https://svs.gsfc.nasa.gov/5548/
Credit: NASA’s Scientific Visualization Studio

Anthocyanins are the red pigments in leaves, while carotenoids are the yellow pigments – both of which we see when autumn changes the colors of trees. Plants use these pigments to protect themselves from fluctuations in the weather, adapting to the environment through chemical changes in their leaves. For example, leaves can turn more yellow when they have too much sunlight but not enough of the other necessities, like water and nutrients. If they didn’t adjust their color, it would damage the mechanisms they have to perform photosynthesis.

In the visualization, the data is highlighted in bright colors: magenta represents anthocyanins, green represents chlorophyll, and cyan represents carotenoids. The brighter the colors are, the more leaves there are in that area. The movement of these colors across the land areas show the seasonal changes over time.

In areas like the evergreen forests of the Pacific Northwest, plants undergo less seasonal change. The data highlights this, showing comparatively steadier colors as the year progresses.

The combination of these three pigments helps scientists pinpoint even more information about plant health.

“Shifts in these pigments, as detected by PACE, give novel information that may better describe vegetation growth, or when vegetation changes from flourishing to stressed,” said McKibben. “It’s just one of many ways the mission will drive increased understanding of our home planet and enable innovative, practical solutions that serve society.”

The Ocean Color Instrument on PACE collects hyperspectral data, which means it observes the planet in 100 different wavelengths of visible and near infrared light. It is the only instrument – in space or elsewhere – that provides hyperspectral coverage around the globe every one to two days. The PACE mission builds on the legacy of earlier missions, such as Landsat, which gathers higher resolution data but observes a fraction of those wavelengths.

In a paper recently published in Remote Sensing Letters, scientists introduced the mission’s first terrestrial data products.

“This PACE data provides a new view of Earth that will improve our understanding of ecosystem dynamics and function,” said Fred Huemmrich, research professor at the University of Maryland, Baltimore County, member of the PACE science and applications team, and first author of the paper. “With the PACE data, it’s like we’re looking at a whole new world of color. It allows us to describe pigment characteristics at the leaf level that we weren’t able to do before.”

As scientists continue to work with these new data, available on the PACE website, they’ll be able to incorporate it into future science applications, which may include forest monitoring or early detection of drought effects.

By Erica McNamee

NASA’s Goddard Space Flight Center, Greenbelt, Md.

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Last Updated
Jun 05, 2025
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Researchers have now gathered a complete year of PACE data to tell a story about the health of land vegetation by detecting slight variations in leaf colors....

NASA Scientists Find New Human-Caused Shifts in Global Water Cycle

✇NASA
By:Erica McNamee
16 January 2025 at 10:27
3 Min Read

NASA Scientists Find New Human-Caused Shifts in Global Water Cycle

A shallow pool of water over a cracked valley floor underneath a cloudy sky.
Cracked mud and salt on the valley floor in Death Valley National Park in California can become a reflective pool after rains. (File photo)
Credits: NPS/Kurt Moses

In a recently published paper, NASA scientists use nearly 20 years of observations to show that the global water cycle is shifting in unprecedented ways. The majority of those shifts are driven by activities such as agriculture and could have impacts on ecosystems and water management, especially in certain regions.

“We established with data assimilation that human intervention in the global water cycle is more significant than we thought,” said Sujay Kumar, a research scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and a co-author of the paper published in the Proceedings of the National Academy of Sciences.

The shifts have implications for people all over the world. Water management practices, such as designing infrastructure for floods or developing drought indicators for early warning systems, are often based on assumptions that the water cycle fluctuates only within a certain range, said Wanshu Nie, a research scientist at NASA Goddard and lead author of the paper.

“This may no longer hold true for some regions,” Nie said. “We hope that this research will serve as a guide map for improving how we assess water resources variability and plan for sustainable resource management, especially in areas where these changes are most significant.”

One example of the human impacts on the water cycle is in North China, which is experiencing an ongoing drought. But vegetation in many areas continues to thrive, partially because producers continue to irrigate their land by pumping more water from groundwater storage, Kumar said. Such interrelated human interventions often lead to complex effects on other water cycle variables, such as evapotranspiration and runoff.

Nie and her colleagues focused on three different kinds of shifts or changes in the cycle: first, a trend, such as a decrease in water in a groundwater reservoir; second, a shift in seasonality, like the typical growing season starting earlier in the year, or an earlier snowmelt; and third a change in extreme events, like “100-year floods” happening more frequently.

The scientists gathered remote sensing data from 2003 to 2020 from several different NASA satellite sources: the Global Precipitation Measurement mission satellite for precipitation data, a soil moisture dataset from the European Space Agency’s Climate Change Initiative, and the Gravity Recovery and Climate Experiment satellites for terrestrial water storage data. They also used products from the Moderate Resolution Imaging Spectroradiometer satellite instrument to provide information on vegetation health.

“This paper combines several years of our team’s effort in developing capabilities on satellite data analysis, allowing us to precisely simulate continental water fluxes and storages across the planet,” said Augusto Getirana, a research scientist at NASA Goddard and a co-author of the paper.

The study results suggest that Earth system models used to simulate the future global water cycle should evolve to integrate the ongoing effects of human activities. With more data and improved models, producers and water resource managers could understand and effectively plan for what the “new normal” of their local water situation looks like, Nie said.

By Erica McNamee
NASA’s Goddard Space Flight Center, Greenbelt, Maryland

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