Landsat program

NASA’s Tips For Interpreting Satellite Images.

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Example tip: Farmed vegetation often looks brighter green than natural vegetation

satellite image of the Okanogan-Wenatchee National Forest in Washington state

Straight Lines Mark Off Land Parcels in a Mixed-Use Forest.
NASA Earth Observatory image by Robert Simmon, using Landsat 8 data from the USGS Earth Explorer

Here at Popular Science, we love satellite images. They offer cool views of Earthly phenomena such as plankton blooms and erupting volcanoes. They give important perspective on the impact of natural disasters such as floods and fires. Seeing stuff from space can be a bit disorienting, however. But fear not. The Earth Observatory, NASA’s public site for its Earth sciences, has listed some cool patterns to look for while interpreting satellite images. Some highlights:

  • A line of clouds can indicate there are mountains below, as the mountains push warmer air upwards to higher elevations, where it cools and forms clouds. A line of vortices in the ocean, on the other hand, can indicate there are peaks below the surface of the water, perturbing the water’s flow.
  • There’s an optical illusion called relief inversion that can happen with satellite images. Mountains appear to be canyons, or vice versa. The Earth Observatory explains:

    It happens because most of us expect an image to be lit from the top left corner. When the sunlight comes from another angle (especially from the lower edge), the shadows fall in ways we don’t expect and our brains turn valleys into mountains to compensate. The problem is usually resolved by rotating the image so the light appears to come from the top of the image.

  • Farmed plants often look brighter green than natural vegetation.
  • Smoke often looks smoother than clouds. Haze is featureless and may be opaque if it’s dense, or translucent if it’s thinner. It’s not always possible to tell, just from visual inspection, the difference between white haze and natural fog.

Happy Earth-watching.

2012 Awards Presented For Achievements in Earth Remote Sensing.

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NASA and the Department of the Interior’s U.S. Geological Survey (USGS) presented the 2012 William T. Pecora awards for achievement in earth remote sensing to Gilberto Camara of Brazil’s National Institute for Space Research and Leung Tsang of the University of Washington in Seattle.

Camara was recognized for his contributions to remote-sensing leadership as a scientist, program director, manager and agency head. Tsang is one of the world’s leading experts on the theory of microwave remote sensing for geophysical environments. Camara received his award at a meeting of the Group on Earth Observations in Foz do Iguacu, Brazil, on Nov. 22. Tsang received his award Tuesday at the American Geophysical Union meeting in San Francisco.

“Along with the immensely successful Landsat program, the Pecora awards are a testament to the very high value both the U.S. Geological Survey and NASA place in Earth remote sensing,” said USGS Director Marcia McNutt. “As our planet’s water, soil, and ecosystems continue to be stressed by a growing population and changing climate, it is essential we continue into a fifth decade of Earth observation time series and recognize the excellence of remote-sensing experts.”

NASA and the Department of the Interior present individual and group Pecora Awards to honor outstanding contributions in the field of remote sensing and its application to understanding Earth. The award was established in 1974 to honor the memory of William T. Pecora, former USGS director and undersecretary of the Department of the Interior. Pecora was influential in the establishment of the Landsat satellite program, which created a continuous, 40-year record of Earth’s land areas.

“I am sure Dr. Pecora would be pleased if he were here with us today and could see how his vision for innovative remote-sensing technology has been realized in the work of the individuals we are recognizing this year,” said astronaut John Grunsfeld, NASA’s associate administrator for the Science Mission Directorate.

As the former director general of Brazil’s National Institute for Space Research, Camara championed broad, open data-sharing policies and practices within the institute that have significantly influenced other domestic and international organizations to emulate this approach. Camara has advanced the linkages between and among remote-sensing technologies and Geographic Information System technologies and applications.

Camara also supported programs within the institute to link moderate-resolution imagery from the China-Brazil Earth Resources Satellite, Landsat, and other Earth observation missions with the policy needs of the Brazilian government, most notably polices on forestation and deforestation in the Amazon.

Tsang’s contributions to microwave remote sensing have laid the groundwork for improved data analysis and designs of new measurements and satellite observational systems. His work has resulted in numerous societal benefits, including monitoring climate change and improving management of water and agricultural resources. His original and pioneering discoveries have resulted in the publication of more than 260 journal articles and four books.

Tsang also made major advances in rough surface scattering theory and applications to microwave remote sensing of soil and vegetated surfaces. He developed an improved modeling framework for rough surface and vegetation scattering with fast computational methods that can be directly applied to both active and passive microwave remote sensing of soil moisture.

Source:NASA

New NASA Supercomputer Facility Set to Advance Earth Research .

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NASA soon will open a new chapter of discovery using enhanced Landsat Earth-observing data in a state-of-the-art, high-performance computing and data access facility called NASA Earth Exchange (NEX). This new facility is a virtual laboratory that will allow scientists to tackle global Earth science challenges with global high-resolution satellite observations.

After extensive development and testing, NASA is making the NEX facility available to the research community for further research and development. With NASA’s state-of-the-art supercomputing capacity, researchers can use NEX to explore and analyze large Earth science data sets in hours rather than months. Scientists can produce complex, interdisciplinary studies of world phenomena and share their findings instantly on the NEX platform.

“Because of the large volume of high-resolution Landsat data, scientists who wanted to study the planet as a whole prior to NEX needed to invest tremendous amounts of time and effort to develop high-end computational methods rather than focus on important scientific problems,” said Tsengdar Lee, high-end computing program manager at NASA Headquarters in Washington. “NEX greatly simplifies researchers’ access to and analysis of high-resolution data like Landsat.”

This new facility boasts a large collection of global data sets and analysis tools from NASA and other agencies, including surface weather records, topography, soils, land cover and global climate simulations. Using NEX, scientists now can fit Landsat scenes together like a giant jigsaw puzzle to create snapshots of global vegetation patterns containing more than a half-trillion pixels in less than 10 hours. These global vegetation products, referred to as the Normalized Difference Vegetation Index, complement the more standard products from the Moderate Resolution Imaging Spectroradiometer on NASA’s Aqua satellite but with 10 times higher resolution.

“The science community is under increasing pressure not only to study recent and projected changes in climate that likely impact our global environment and natural resources, but also to design solutions to mitigate, or cope, with the likely impacts,” said Rama Nemani, a senior Earth scientist at NASA’s Ames Research Center in Moffett Field, Calif. “We want to change the research paradigm by bringing large data holdings and supercomputing capabilities together, so researchers have everything they need in one place.”

Developed by a team at Ames, NEX combines Earth-system modeling, remote-sensing data from NASA and other agencies, and a scientific social networking platform to deliver a complete research environment. Users can explore and analyze large Earth science data sets, run and share modeling algorithms, collaborate on new or existing projects and exchange workflows and results within and among other science communities.

Scientists believe costs and time associated with research development may be reduced significantly by allowing NEX members to collaborate instantly in this type of large-scale supercomputing work environment. For example, NEX may relieve researchers from redundantly retrieving and integrating data sets and building modeling analysis codes.

NEX uses Landsat data, which constitute a large collection of images collected over 40 years by a series of satellite sensors. The enhanced collection of Landsat data gives scientists the opportunity to study and understand changes on a planetary scale, looking at one-quarter acre at a time.

NASA, in cooperation with the Interior Department and its science agency, the U.S. Geological Survey, launched the first Landsat satellite in 1972. The resulting 40-year archive of Earth observations from the Landsat fleet supports the improvement of human and environmental health, biodiversity, energy and water management, urban planning, disaster recovery and crop monitoring. The Landsat program is jointly managed by NASA and the Interior Department.

Source:NASA