Managing Rangeland Health

More than 70 percent of Montana’s land area, or 68 million acres, is covered in rangelands. Cattle roam and forage across these wide-open spaces, and the beef industry is worth $2.2 billion to the State. For decades, invasive plant species such as Bromus tectorum L. (cheatgrass) have infiltrated Montana, overwhelming sagebrush landscapes and creating substantial fire risk. Landsat observations help research teams to build tools that can guide wise decisions on invasive species management in Montana. In the late 2010s, the Western Governors’ Association partnered with the University of Montana to build a Landsat-based tool that breaks rangelands into their component parts (sagebrush, annual herbaceous, bare ground, and so on). These categorizations and related analyses help land managers target areas of invasion for restoration, preserve uninvaded areas, and assess wildfire risk (U.S. Geological Survey, 2020).

Monitoring Mountain Snow and Ice

The wonders of Glacier National Park thrill visitors, but warming temperatures and shifting climate patterns have had a substantial effect on the namesake features of the 1,583-square-mile wilderness preserve. The USGS Northern Rocky Mountain Science Center has documented losses in all glacial areas of the park since 1966, with an average area reduction of 39 percent and a maximum of 85 percent at Boulder Glacier (Florentine, 2019). That reality has implications well beyond visitor satisfaction; glacial meltwater is an important source of moisture and streamflow in Montana. Landsat’s long-term, repeat observations help research teams to track glacial retreat. One team of researchers built an automated system for mapping persistent snow and ice cover across the United States in 2015 using Landsat data. They determined that snow and ice cover has declined at an even greater rate than had been previously estimated (Selkowitz and Forster, 2016).

Tracking Water Use from Space

Nearly 2 million acres of Montana cropland was irrigated in 2019, making irrigation an important component of the State’s $4.4 billion agriculture industry. Competition for scarce water resources is among the reasons farmers, ranchers, water managers, and researchers lean on Landsat. Thermal sensors make it possible to map evapotranspiration (ET), or the combined rate of water loss through evaporation from the Earth’s surface and transpiration from plant leaves. Absent satellite observations, the measurement of ET can only be completed with flux towers on the ground. Multiple researchers have formulated methods for calculating ET estimates at a wide scale using Landsat observations, which can help guide resource allocation decisions; for example, USGS researchers have used ET models developed by the USGS EROS Center to track field-scale water use across the St. Mary-Milk River drainage basin for the U.S.-Canada International Joint Commission, which manages lakes and rivers at the United States-Canadian border (U.S. Geological Survey, 2021).

Landsat—Critical Information Infrastructure for the Nation

Landsat is the most widely used land remote sensing data source within Federal civilian agencies. Local, State, Tribal, and Federal agencies use Landsat to monitor and forecast a wide range of land surface phenomena. Information from Landsat contributes to day-to-day decisions on land, water, and resource use that protect life and property; safeguard the environment; advance science, technology, and education; support climate change resiliency; and grow the U.S. economy. Landsat’s imagery provides a landscape-level view of land surface, inland lake, and coastal processes, both natural and human-induced. Landsat enables us to better understand the scope, nature, and speed of change to the natural and built environment.

Businesses draw upon Landsat data to provide customer-specific applications to improve logistics, resource allocation, and investment decisions. Commercial space imaging firms leverage Landsat data to refine product offerings and support new information services. A 2017 USGS study determined the total annual economic benefit of Landsat data in the United States to be $2.06 billion, far surpassing its development and operating costs (Straub and others, 2019).

Landsat 8 and Landsat 9 provide 8-day repeat coverage of the Earth’s land surfaces. The National Aeronautics and Space Administration (NASA) and the USGS are currently reviewing the findings from a joint Architecture Study Team, which will inform the design and implementation approach for Landsat Next, the follow-on mission to Landsat 9. Landsat 9 and its successors are planned to provide a sustainable, space-based system to extend the 50-year Landsat series of high-quality global land imaging measurements—the world’s longest time series of the Earth’s land surface.

The long-term availability of consistent and accurate Landsat data, combined with a no-cost data policy, allows users to analyze extensive geographic areas and better understand and manage long-term trends in land surface change. New cloud computing and data analytics technologies use Landsat data in a wide range of decision-support tools for Government and industry. Much like global positioning systems and weather data, Landsat data are used every day to help us better understand our dynamic planet.