We live on a
water planet. From millions of miles away, Earth
shines blue, with almost 70% of its surface covered
in water. But most of that water is in the oceans,
it’s salty. On Earth, only about 3%
of water is fresh — the stuff we drink and use
to feed our crops — and it’s constantly moving:
Through the atmosphere, soil,
aquifers deep underground, and even living things. That’s where NASA
satellites come in. Taking a global look at freshwater provides
important information about droughts, floods
and water quality around the globe. The more we know
about water and its availability, the better decisions we can
make about how to manage it. From identifying food insecurity
before aquifers run dry, to pinpointing when
and where rivers will flood, tracking water from space
gives us an advantage in using it. For example:
Looking deep underground, the Gravity Recovery and Climate Experiment,
or GRACE mission, measured water stored in
aquifers. When human activity and drought drain aquifers,
they can be replenished by sufficient precipitation…but they aren’t always.
GRACE watched how water moved in and out of
aquifers from 2002 to 2016.
Closer to our feet, water in the soil changes quickly in response to precipitation.
We can see soil get wetter in response to rainfall, and about a month later,
watch as vegetation blooms where the soil is sufficiently
moist. We can track all of these steps with satellites,
which help us predict where food insecurity may crop up
before it becomes a problem. Satellites help us track
rivers and lakes, too. Reservoirs can become contaminated by
blooms of algae, which grow in response to fertilizer running off
from farms and cities. In the upper Midwestern U.S., there are hundreds
of lakes, so it can be difficult to track them all individually.
A view from space helps us keep an eye on lakes with blooming algae.
Rivers are an important source
of water for communities around the globe, and often, these
rivers originate as snow high in the mountains.
Snowpack, or the amount of snow and accumulates on the ground,
feeds rivers on a seasonal basis.
Earlier snowmelt can affect how and where water is available for irrigation.
And as the climate continues to warm, snowpack is disappearing at lower altitudes,
and what does exist is melting faster.
Our planet is constantly in motion, with freshwater shifting
around the globe. Those changes are happening faster in a warming world,
with precipitation falling in different places, and rivers
flowing new speeds. NASA’s view
of where freshwater is, and how it moves, is even
more important than ever. From deep below
the ground up into the atmosphere, we’re helping manage their water better.
EXPLORE EARTH NASA