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.”
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.
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Source: NASA’s PACE Mission Reveals a Year of Terrestrial Data on Plant Health - NASA
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