If you want to know how much rain fell yesterday, you can catch it and measure it. Water vapor? That's not so easy. Which is a problem if you want to know how quickly that rate is returning to the atmosphere. Water vapor is the single largest part of the water budget, but without space-based observations, it would be all but impossible to measure at wide scale. On this episode of Eyes on Earth, we learn how a sensor called ECOSTRESS helps improve the space-based measurement of evapotranspiration, or ET, which is the combined rate of evaporation from the Earth's surface and transpiration from plants.

The rangelands of the western United States are changing more quickly than many other parts of the lower 48. Miles upon miles of the area or semi-arid landscapes in states like Idaho, Montana and Nevada are now carpeted by fire fueling invasive grasses. Cheatgrass is the most prevalent, which is troublesome for several reasons. First off, it greens up and browns down really quickly, leaving a layer of tinder-like vegetation. In many areas, it fills in the formerly barren spaces between thicker bunchgrasses and sagebrush, which in turn helps fires move rapidly from fuel source to fuel source. On this episode of Eyes on Earth, we hear from the USGS EROS teams who use satellite data to map exotic annual grasses and a researcher who uses those maps to create monthly grass abundance estimates for firefighters and land managers.

Satellites like Landsat are valuable for mapping fire perimeters and for monitoring trends in burn severity or in post-fire recovery. Satellites can cover wide areas with a single pass, whereas helicopter, drone, or airplane fire line mapping can take hours. But civilian satellites with moderate resolution typically don't get imagery for the entire planet every day, and every day counts when large fires rage. On this episode of Eyes on Earth, we talk through a tool called RADR-Fire built to pull data from a wide variety of sources to map disaster impacts on a day-by-day basis. ECOSTRESS, a sensor on the International Space Station whose data are archived at the NASA’s EROS-based Land Processes Distributed Active Archive Center (LP DAAC), has been an especially useful source of information.

Outbreaks of native bark beetles can lead to conspicuous changes in a forest landscape. They’ve been present for thousands of years with occasional outbreaks, but there’s a lot we don’t yet understand about them. Exactly when and where have outbreaks occurred? How severe were they? What happened to the forest afterward? How will a warming climate influence outbreaks? On this episode of Eyes on Earth, we hear from researchers Dr. Sarah Hart and Dr. Kyle Rogers, who use Landsat to help find answers to those questions. A recent study led by Dr. Rodman used Landsat to identify the locations and severity of bark beetle outbreaks in the southern Rocky Mountains. The researchers were surprised to find smaller areas of severe mortality than they expected. Landsat can even be used to help predict patterns of future outbreaks. Dr. Zhiliang Zhu, a USGS researcher, adds his perspective of the effects of forest disturbance as well.

Fires can be destructive or healthy for a landscape—often both. Fires have grown larger and more destructive in recent years, though, thanks to human activity, climate change, and a host of other factors. Satellite data helps us to map and monitor fire activity, but the study of post-fire plant life using remote sensing data goes further than fire mapping. On this episode of Eyes on Earth, we hear from Dr. Helen Poulos, who used data from the ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station, (ECOSTRESS), to study Arizona Pine Oak forest 5-7 years after severe fire. Dr. Poulos and her collaborators at Northern Arizona University and the University of Maine at Farmington learned that post-fire shrublands had surprisingly high rates of water use. ECOSTRESS data are available through NASA’s Land Processes Distributed Active Archive Center or LP DAAC, which is located at EROS.

For our third and final episode of Eyes on Earth from the September launch of Landsat 9, we hear from Virginia Norwood. She blazed a trail for women in remote sensing in the 1960s and 70s while working for Hughes Aircraft, a contractor for NASA. Norwood is known as the “Mother of Landsat” for her design of the Multispectral Scanner, or MSS, the sensor used to image the Earth’s surface by early Landsat satellites. Norwood met her fans during a Q&A a few hours after the launch sponsored by the USGS and Ladies of Landsat. The episode also features an appearance from Kass Green, who founded a company in the 1980s that used Landsat data to map landscape change.

Hundreds of scientists, officials, international representatives, and others witnessed the launch of Landsat 9 on September 27, 2021, from a handful of viewing sites around Santa Barbara County, California. Their interests were as varied as their backgrounds, but the new satellite’s extension of the Landsat program’s invaluable 50-year record of Earth observations was top of mind for the international partners who help the USGS collect Landsat data and the scientists who rely on those data to monitor the health of the planet. In this episode of Eyes on Earth, we talk with guests from around the world about their role in the Landsat program, and the importance of the program to their work.

Landsat 9 launched into orbit from Vandenberg Space Force Base on Monday, September 27, 2021, to carry on the legacy of a nearly 50-year record of continuous Earth observation that began in 1972. The days leading up to the event saw guests from around the world descend upon Santa Barbara County in California to watch the historic event take place. Over the next few weeks, we’ll bring you some of the interviews we collected with scientists, government officials and Mission partners. This episode of Eyes on Earth focuses on the day before the launch, when we spoke about the importance of the Landsat program with guests at the launchpad and a Landsat for Climate event.