Audio

When a disaster like a hurricane, flood or major wildfire hits a remote part of the world, the International Charter Space and Natural Disasters springs into action.

Evapotranspiration is the process by which water transpires from the leaves and stems of plants and evaporates from the Earth’s surface. ET is an important metric for managing water use, but data availability has long been an issue.

Today, the world is awash in remotely sensed data. Satellites launched by countries and commercial companies circle the planet collecting data every day. Accessing data from multiple agencies and plaforms and turning it into useful analytics can be a daunting and complex endeavor, however.

Mapping land cover across the United States using Landsat satellite data is a difficult, time-intensive job, but there are jobs far larger. Matt Hansen, a Maryland-based professor and member of the Landsat Science Team focuses his efforts on mapping land cover and change on a global scale.

Calibration teams at the USGS EROS Center use a variety of methods to make sure the data collected by Landsat satellites are an accurate representation of the Earth’s surface.

Just recently, in mid-July, the flight operations team charged with keeping the Landsat 7 satellite running smoothly achieved a major milestone. They have gone 8 straight years now without an operator error.

In the days before LANDFIRE, fire scientists often struggled to find the vegetation and fuels data they needed to map the path of fires, keep firefighters safe, and to model fire recovery.

The U.S. Geological Survey took a bold step toward documenting change across the landscape with the launch of the first Landsat satellite in 1972. Since then, it’s collected nearly five decades of imagery. But it takes more than just imagery to understand change. It takes time, effort—and serious computing horsepower.

Remote sensing is not an especially venerable scientific discipline, at least in comparison to fields like biology, chemistry or medicine.

The continent of Australia experienced some of the most devastating wildfires in its history in late 2019 and early 2020. Remote sensing scientists in Australia, who collaborate closely with EROS, relied on satellites like Landsat to help assess and monitor the damage.

Between them, Landsats 7 and 8 image the entire land surface of Earth every eight days. The USGS orbiters are just two of many Earth observing satellites flying at the same altitude and collecting data at the same time of day.

Sea levels are rising globally. In some places, it is rising more than others, threatening communities and people as storm surges reach further inland and inundate more land.

The U.S. has plenty of data on wildfire risk. There are local and regional risk assessments, complex datasets like LANDFIRE and tracking tools like the EROS Fire Danger Monitor, as well as a host of resources and research projects devoted to the subject.

Landsat satellites offer a wealth of information to scientists studying ecosystem health and recovery. Data products derived from Landsat open even more areas of inquiry. Landsat Burned Area products, for example, can help researchers identify previously unknown fires that took place from 1984 through the present.

The Mendenhall Program offers a range of two-year post-doctoral research fellowships within the U.S. Geological Survey. Heather Tollerud took advantage of the program in 2015 to study drought and land cover at the USGS EROS Center, and has since become a key player in the Center’s innovative Land Change Monitoring, Assessment and Projection (LCMAP) initiative.

In the West African nation of Ghana, tropical forests are more than landscape. They are woven into language, custom, and culture. They are also the source of timber for home heating and industry, as well as barriers to agricultural production. Those are just a few of the reasons why deforestation has come alongside the nation’s rapid population growth.

The Arctic is changing at a more rapid rate than the rest of the planet. Some of the most significant changes are tied to the thawing of near-surface permafrost, the layers of frozen soil containing vast stocks of stored carbon.

For decades, each Landsat image had a price tag – a hefty one at times, ranging from $400 to as much as $4,000. That all changed in 2008 with the enactment of an open data policy that made the entire Landsat archive available for download at no cost to the user.

Across the planet, in rural settings on uncluttered landscapes, there are satellite antennas receiving data directly from Landsat satellites as they pass 438 miles overhead at more than 17,000 miles per hour. It happens multiple times a day, in Australia, Brazil, Canada, Germany, South Korea, and elsewhere.

It’s easy enough to measure rainfall, and nearly as easy to measure streamflow. Calculating the efficiency of water use through the metric of evapotranspiration (ET) – evaporation off the Earth’s surface and transpiration from the leaves of plants – is a far trickier proposal.

Land cover and land use across the United States are the culmination of a complex web of interwoven factors: Climate, landscape types, and economic factors among them. Remotely-sensed data from satellites like Landsat and a variety of other sources are useful for documenting and monitoring land cover and land use.