GLOBE News
GLOBE and PACE collaborate to monitor plant color changes
The GLOBE North American Phenology Campaign, which has collected Green-down data (leaf color change) since 2023, expanded this year to include land cover observations for NASA’s PACE (Plankton, Aerosol, Cloud, and ocean Ecosystem) satellite mission. GLOBE volunteers have been submitting photos through the GLOBE Observer app’s Land Cover tool showing fall colors on the forested landscape.
What is PACE?
PACE terrestrial scientists Skye Caplan and Fred Huemmerich are using the satellite to understand plant health and seasonal changes over time using leaf pigments. PACE-observed pigment changes can help scientists understand forest productivity (the breakdown of chlorophyll in leaves ends photosynthetic activity), surface energy balance (changes in leaf color alter absorption of sunlight), and fall tourism (viewing fall foliage is a significant activity in some regions). Changes in pigments can also occur when vegetation is stressed due to drought or insect damage.
The satellite observes the Earth through three on-board instruments that measure wavelengths of light (color); each instrument uses different technologies to record color in the oceans, in clouds, and on land. PACE is able to monitor multiple pigments and more often than previous missions; the satellite makes a complete pass over Earth every one to two days.
PACE uses reflected light at very specific wavelengths to capture the red (anthocyanin) and green (chlorophyll) pigments in plants. Those pigments can then be compared to assess which color is most dominant on a broad scale. When enough reds overtake the greens, the leaves start to change color to the human eye.
How can GLOBE volunteers help?
Caplan and Huemmerich are trying to discover if the pigments observed through the satellite match what is seen on the ground. This is where volunteer observations are valuable. The phenology campaign is specifically looking at fall leaf colors, and volunteers are helping to confirm that the satellite data are tracking what is being observed. Anyone can participate by downloading the GLOBE Observer app and using the Land Cover tool. Instructions can be found on the phenology campaign webpage.
What are the results so far?
In mid-September, Caplan and Huemmerich began providing weekly visualizations of plant pigment changes both across North America and globally. They have also written short descriptions of what can be seen in the visualizations. All the updates can be found on the PACE Fall Foliage Updates page.
The campaign will be wrapping up in December, and results will be shared soon after.
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More information:
- The U.S. GLOBE Office has many resources available on the North American Phenology Campaign webpage, including educator teaching sequences and an implementation toolkit for community-based organizations.
- There are also PACE-specific resources available, including visualizations, webinar recordings, and GLOBE learning activities.
- Two webinars with Caplan and Huemmerich can be found on the phenology campaign Webinars page.
News origin: United States of America