NASA's Space Place
Where’s the Water?
National Aeronautics and Space Administration
Since NASA explores our solar system and other galaxies, you might think we don’t need to explore our own planet anymore. It’s not true, though. It’s easy to forget that there are lots of things about Earth we still don’t know. We’ve got a lot to learn.
One area that deserves exploring is Earth’s supplies of water, especially in the soil. A new NASA spacecraft called Soil Moisture Active Passive, or SMAP, is orbiting Earth right now. It will measure moisture in the top five centimeters (about two inches) of soil all over the world. This soil is very important, since it’s where most plants live. SMAP detects how much water is in the soil. It can also tell if the water is frozen or thawed.
SMAP isn’t going to take soil moisture measurements just once. It’s going to gather information every two or three days for three whole years. That means we’ll be able to see changes over time. It also means that the effects of storms, droughts, and seasons can be watched closely. Then we can see how they all affect soil moisture.
Getting measurements of soil moisture every few days for years is going to produce a lot of information. What will scientists do with it? They’ll be able to observe and predict droughts, which can have big impacts on food supplies. SMAP will also help predict dangerous weather. Storm clouds form from evaporated water. Knowing how much water is in the soil means you can guess how much can evaporate and lead to storm clouds. Also, if the ground is so full of water that it can’t hold any more, with a big rainstorm on the way, there could be a flood.
In the end, SMAP will help us better understand how the water cycle works. How water moves from the ground to the air can be traced through soil moisture. Gathering information about this can help us understand many things. It will lead to a deeper understanding of our planet, how things are connected, and how we can preserve our planet for the future.
Learn about how some of Earth’s water may have been delivered by comets! http://spaceplace.nasa.gov/comet-ocean.
NASA's Soil Moisture Active Passive (SMAP) mission will produce high-resolution global maps of soil moisture to track water availability around our planet and guide policy decisions. Image Credit: NASA/JPL-Caltech