How NASA measures Earth's water from space

The U.S. Drought Monitor shows that nearly the entire state of California is experiencing an “exceptional drought” – the most severe classification.  

The Central Valley, home to one of the most productive agricultural regions in the world, has been the hardest hit.  So it’s no surprise that water levels in the state’s reservoirs are dropping to historic lows as we anxiously sit in anticipation of rain.

In search of scientific solutions, TechKnow paid a visit to some scientists from NASA’S Jet Propulsion Lab who are using satellites and other airborne missions to track and measure changes in our water supply.

JPL’s senior water scientist, Jay Famiglietti, tells us that NASA’s GRACE Satellites (Gravity Recovery And Climate Experiment) which launched in 2002, surveys the Earth’s fresh water from space. The satellite shows how much water is available in underground reservoirs, and his team tracks how these water reserves are changing. Before GRACE, there was no other way to measure how much water was underground.

Famiglietti is optimistic about a new water related satellite mission called SMAP (Soil, Moisture, Active, Passive) which will measure how much water is in the Earth’s soil and be able to predict future droughts.  These ongoing measurements will not only provide valuable data to improve water management, but will also help farmers understand what’s going on with their water supply.  This will allow them to explore alternative plans to maximize their crops.

Across JPL’s campus in the Snow Optics Lab we met snow hydrologist, Tom Painter, who leads a mission called “The Airborne Snow Observatory.”

Painter and his team outfitted a twin-engine plane with high tech equipment to measure the Sierra Nevada Mountain snowpack from 20,000 feet.  The snowpack melts and releases water. This mission has gathered unprecedented data revealing exactly how much water is contained in the snow, and how much water is expected to flow out of the basin through the mountain reservoir.  According to Painter, 75% to 80% of our water comes from the snowmelt, and now his team provides this critical information to water managers, farmers, and state officials, calculating exactly how much water they can expect from the snow run off – an invaluable water resource.

We don’t know how much longer California will be experiencing exceptional drought, but with the advances in space technology at NASA’S Jet Propulsion Lab, scientists are measuring what our eyes cannot see, and helping us understand how our water supply is changing.  The mission here is, with these detailed models and measurements, we will have better estimates of water availability for agriculture and municipalities, and more importantly, the ability to plan, and mitigate impacts of drought in years to come.