On Feb. 11, NASA’s Landsat Data Continuity Mission (LDCM) thundered into space aboard an Atlas V rocket launched from Vandenberg Air Force Base, Calif.
The LDCM, the eighth satellite in a series dating back to 1972, brings two sensors—the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS)—into low orbit over the Earth to image our planet's land surface.
Jim Irons, a former agronomist serving as NASA project scientist for LDCM at NASA's Goddard Space Flight Center, Greenbelt, Md., says that the new satellite and imaging instruments will deliver data-rich images for growers and other agricultural decision makers, telling a deeper tale of how the land changes over time.
“Landsat data are applied broadly in agriculture,” explains Irons. “The USDA Foreign Ag Service uses Landsat data to help develop their global commodity forecasts, the USDA National Agricultural Statistical Service (NASS) uses Landsat data in the development of its now annual Crop Data Layer (CropScape) digital map of U.S. crops, and the USDA Risk Management Agency uses Landsat data to spot check crop insurance claims, validate cause of loss and assess flood risk and compliance.
“Additionally, our western states’ water resource agencies use Landsat data to monitor water consumption in irrigated fields, to manage water rights and adjudicate conflicting claims,” he adds.
According to NASA, LDCM will go through what’s known as a “check-out phase” for the next three months. Afterward, operational control will be transferred to NASA's mission partner, the Department of the Interior's U.S. Geological Survey (USGS), and the satellite will be renamed Landsat 8. Data will be archived and distributed free over the Internet from the Earth Resources and Science (EROS) center in Sioux Falls, SD. Distribution of Landsat 8 data from the USGS archive is expected to begin within 100 days of launch.
To demonstrate the benefits of the launch to agriculture, NASA recently profiled grower Gary Wagner, who uses free data obtained from LDCM satellites to make variable-rate fertilizer decisions on his 5,000 acre sugarbeet farm in northern Minnesota.
From NASA’s "Landsat Satellites Find the 'Sweet Spot' for Crops"; To find where he needs to adjust his fertilizer use—apply it here or withhold it there—Wagner uses a map of his 5,000 acres that span 35 miles created using free data from NASA and the U.S. Geological Survey's Landsat satellites. When he plants a different crop species the following year, Wagner's map will tell him which areas of the fields are depleted in nitrogen so he can apply fertilizer judiciously instead of all over.
Wagner's map—a special kind of map known as a zone map—shows the difference between healthy and stressed plants by representing the amount of light they're reflecting in different bands of the electromagnetic spectrum. To display this information on his map, the visible colors of light—red, green, and blue—are each assigned to a different band. Red, for example, is assigned to the near-infrared band that isn't visible to humans. Healthy leaves strongly reflect the invisible, near-infrared energy. Therefore green, lush sugar beets pop out in bright red on Wagner's map, while the yellow-leaved stressed plants appear as a duller red. Wagner can use this map to track and document changes in his crop’s condition throughout the season and between seasons. As a tool, this map supports and enhances his on-the-ground crop analyses with independent and scientific observations from space.
A farmer needs to monitor his fields for potential yield and for variability of yield, Wagner says. Knowing how well the plants are growing by direct measurement has an obvious advantage over statistically calculating what should be there based on spot checks as he walks his field. That's where remote sensing comes in, and NASA and the U.S. Geological Survey's Landsat satellites step into the spotlight.