National Drought Mitigation Center


Drought Center researchers "aboard" NASA soil moisture mission as early adopters

January 26, 2015

NASA''s Soil Moisture Active Passive mission features an orbiting observatory that will measure water content of the top two inches of soil that is not frozen. Image courtesy of NASA Jet Propulsion Laboratory

NASA chose researchers associated with the National Drought Mitigation Center (NDMC) and the U.S. Drought Monitor (USDM) to be early adopters of the soil moisture data from a new satellite mission, which is slated to launch on Jan. 29, for drought monitoring. The NDMC is based at UNL.

“As we get these data at a high resolution, covering the entire country, we’re going to do our jobs better,” said Brian Fuchs, NDMC climatologist and U.S. Drought Monitor author. “When you see the Drought Monitor map coming out each week we’re going to have more confidence in some of the inputs that we’re looking at, especially with regards to soil moisture. They’re going to be of a high level, greater quality and more utility than anything we’ve had up to this point.”

The NASA Soil Moisture Active Passive (SMAP) mission is expected to provide far better data about soil moisture information than anything that has been available to this point. Soil moisture, necessary for crops and other plants to grow, is a key indicator of agricultural drought.

“Soil moisture is really a critical component in understanding drought -- where it’s developing, how severe it is,” said Brian Wardlow, an expert on remote sensing of drought. “Traditionally, soil moisture information has been acquired by ground-based measurements or probes in the soil, which are few and far between. So we’re interested in SMAP to give us more detailed information on soil moisture variations across large areas, really fill in the gaps between where these sensors are on the ground, and to give us a more detailed spatial view of how things are changing in the soil over time.” Wardlow, who is affiliated with the NDMC, is director of the Center for Advanced Land Management Information Technologies, which is also based in the School of Natural Resources at the University of Nebraska-Lincoln.

Mark Svoboda, who leads the NDMC’s Monitoring program area and is one of the original U.S. Drought Monitor authors, said, “This will help us better understand the global hydrologic system, and how soil moisture relates to groundwater, surface water and stream flow. It will help us do a better job of drought early warning, especially when we don’t have any in situ data.” In situ data in this context refers to measurements taken by instruments on the ground, as opposed to satellites.

Svoboda and Wardlow said that as early adopters, they will be able to help provide guidance to NASA on how to make the SMAP data as useful as possible within a drought monitoring context, to validate the accuracy and utility of the data for this application, and, assuming it is as accurate as anticipated, to help others use the data operationally in monitoring systems throughout the world.

NASA describes SMAP as an orbiting observatory that will measure the water content of the top 2 inches of soil that is not frozen, and it will revisit most of the globe every few days. At six miles across, the pixels on SMAP-derived maps will be much smaller than the distance between soil monitoring sensors on the ground. In some of the most famine-prone parts of the world, little to no soil moisture information is currently available.

The NDMC research team has a history of working successfully with NASA on applications of its data for drought monitoring and early warning, including the Vegetation Drought Response Index (VegDRI), the Evaporative Stress Index (ESI), and terrestrial water storage anomaly maps based on observations from the NASA GRACE mission.

To learn more about the SMAP mission, please visit