It’s autumn
and things are changing.
Cool air,
hot cider,
and leaves!
As humans
we can see this striking change
in our neighborhoods
or even on a trip.
Fall foliage tourism brings
in tens of billions of dollars
in the U.S. alone.
But there’s more to it
than just a
pretty scene.
The fall colors
signal changes with our food,
our air, our ecosystems.
Photosynthesis ends,
carbon and water balance change,
and leaf color changes
how much sunlight is absorbed.
Now with the PACE satellite,
we’re seeing
seasonal fall foliage
in a whole new view.
PACE can see more information
in leaf color changes
than our eyes can detect,
especially in leaf pigments.
These pigments
protect plants
and allow them to thrive
in changing conditions
and seasons.
Before PACE, we’d
have to infer the timing
of seasonal changes
by how much “green-ness”
has decreased.
By looking at how PACE’s
pigment indices change
relative to one another,
it can give us a view
into the health of ecosystems.
For instance,
a shift in the start of fall colors
could mean drier or colder years.
And data on leaf pigments
could help answer
other science questions.
Like why do trees even turn red?
Is it sun protection
in colder temperatures?
Or warning against
insect damage?
Or something else entirely?
As PACE repeatedly covers
both the land and ocean,
we’ll gather more data
to help us decode
these colors.