Water, Water Everywhere; We Track Drops to Drink!

When we think about what makes a planet habitable, we’re often talking about water. With abundant water in liquid, gas (vapor) and solid (ice) form, Earth is a highly unusual planet. Almost 70% of our home planet’s surface is covered in water!

But about 97% of Earth’s water is salty – only a tiny amount is freshwater: the stuff humans, pets and plants need to survive.

Water on our planet is constantly moving, and not just geographically. Water shifts phases from ice to water to vapor and back, moving through the planet’s soils and skies as it goes.

That’s where our satellites come in.

Look at the Midwestern U.S. this spring, for example. Torrential rain oversaturated the soil and overflowed rivers, which caused severe flooding, seen by Landsat.

Our satellites also tracked a years-long drought in California. Between 2013 and 2014, much of the state turned brown, without visible green.  

It’s not just rain. Where and when snow falls – and melts – is changing, too. The snow that falls and accumulates on the ground is called snowpack, which eventually melts and feeds rivers used for drinking water and crop irrigation. When the snow doesn’t fall, or melts too early, communities go without water and crops don’t get watered at the right time.

Even when water is available, it can become contaminated by blooms of phytoplankton, like cyanobacteria . Also known as blue-green algae, these organisms can make humans sick if they drink the water. Satellites can help track algae from space, looking for the brightly colored blooms against blue water.

Zooming even farther back, Earth’s blue water is visible from thousands of miles away. The water around us makes our planet habitable and makes our planet shine blue among the darkness of space.

Knowing where the water is, and where it’s going, helps people make better decisions about how to manage it. Earth’s climate is changing rapidly, and freshwater is moving as a result. Some places are getting drier and some are getting much, much wetter. By predicting droughts and floods and tracking blooms of algae, our view of freshwater around the globe helps people manage their water.

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