Landsat 8 Goes Over the Top
On June 21, 2014, Landsat 8 acquired an unbroken swath of 52 individual scenes over the Arctic. The midnight sun of the summer solstice allowed scientists to see more of the color and diversity of snow, ice, and cloud formations. Starting in Scandinavia, Landsat 8 cut across the Arctic Circle, northern Greenland, and through Canada’s Nunavut and Northwest Territories. NASA released a video of the imagery, along with close-up views of some favorite scenes, on its NASA Earth Observatory Web site. The swath is a good demonstration of how the Earth-observing satellite can monitor change over time in remote locations on the globe.
Climate and Land Use Change Mission Area
The USGS Climate and Land Use Change Mission Area recently launched an updated and expanded Web site. The site features news, science features, a quarterly newsletter, information on how to access data, and links to specific science activities. Learn more about the science that helps the USGS understand a changing world and how it impacts our natural resources, our livelihoods, and our communities.
Landsat’s Return on Investment
What is the real value of the Landsat program? The Landsat Advisory Group, a team of commercial, state/local government, and non-government geospatial information experts, has been working on an answer. They concluded that the economic value of just one year of Landsat data far exceeds the multi-year total cost of building, launching, and managing Landsat satellites and sensors. It’s a stunning return on investment for the program that collects consistent, continuous land change data and distributes it freely online.
Read the USGS Top Story Science Feature for more details about the study.
Case Studies of Landsat Imagery Use
Open-access Satellite Data
Changes in land cover affect the global climate by absorbing and reflecting solar radiation, and by altering fluxes of heat, water vapor, carbon dioxide, and other trace gases. Detailed assessments—regional, global, daily, and seasonal—of land use and land cover are needed to monitor biodiversity loss and ecosystem dynamics. Satellite imagery is the best source of such data, especially over large areas. In many cases, satellite data are restricted or charged for. Not true for U.S. Geological Survey (USGS) satellite imagery.
A new era of open-access satellite data began in 2008 when the USGS released its Landsat archive, the world’s largest collection of Earth imagery, to the public free of charge. Monitoring land cover change in near-real time is now a reality. According to an article by Michael A. Wulder and Nicholas C. Coops in Nature magazine, “Freely available satellite imagery will improve science and environmental-monitoring products.” Read the full story here.
Observing Earth Today and Tomorrow: A National Plan
Humans have been observing Earth for a very long time simply because the conditions of the Earth are basic to our survival and our prosperity. Even the most ancient written records are filled with accounts of great floods, famines, and earthquakes. When to plant and when to harvest, how to use precious water resources most effectively, and ways to avoid natural disasters are all age-old challenges that have encouraged Earth observation from the beginning of civilization. Read the full story here.
Landsat’s Lunar Scans
Even though Landsat 8 is an Earth-imaging satellite, it was designed to turn away from Earth once a month and scan the moon. Landsat’s sensors need to detect light consistently over time. The best way to measure Landsat’s performance is to compare it to a stable source of light. The calibration team at the NASA Goddard Space Flight Center and the USGS EROS Center use the most stable light source they can—moonlight. With these lunar scans, the engineers can adjust the calculations that turn Landsat’s data into accurate land cover information. Read the full story here and see a video created by NASA Goddard that demonstrates in detail how Landsat 8 conducts its lunar scan.
National Land Cover Database 2011 on YouTube
Learn more about the National Land Cover Database 2011 (NLCD 2011) from Dr. Collin Homer, USGS Earth Resources Observation and Science (EROS) Center. In a YouTube video presentation, Homer describes the status, future plans, and applications examples of NLCD 2011. The presentation clearly describes NLCD’s flagship products: land cover, canopy, and imperviousness. Homer emphasizes that NLCD is valuable because it is consistent and relevant. Its national coverage also supports many different applications: fire, urban development, insect damage, mining, and more. Find out what Homer means by "30 billion pixels served" at https://www.youtube.com/watch?v=GekyUrZoYys.
New Teaching Resource for Remote Sensing
The Tracking Change Over Time lesson is intended for students in grades 5–8. It enhances students’ learning of geography, earth science, and problem solving by seeing landscape changes from space. The lesson plan includes an introduction to satellite images, an introduction to remote sensing, instructions on how to use the free software MultiSpec, and modules that go deeper into specific areas of remote sensing application.
In the latest module, "River Flooding", students discover how a flood in June 2008 affected southern Indiana and Illinois. The module takes a problem-based approach to show students how satellite images can be used to analyze the changes that a flood causes. The images used in the lesson, along with supplementary materials, are also available at http://eros.usgs.gov/educational-activities.
Landsat 7 Marks 15 Years of Observing Earth
For the past 15 years Landsat 7, launched on April 15, 1999, has continued the legacy of Earth observations started by the Landsat program in 1972. Landsat 7’s remarkable longevity has been vital to the majority of Landsat data users who require frequent imaging of specific areas for land and resource management. Today, Landsat 7, working in tandem with Landsat 8, continues to provide a continuous, unbiased record of change across the earth land surface.
For more information about Landsat 7’s first 15 years, please see the USGS Press Release.