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Landsat ETM+
U.S. Geological Survey - no redistribution restrictions
Image acquisition by the Landsat 7 ETM+ is driven by a long term acquisition plan (LTAP) that was designed to optimize the acquisition of seasonal cloud-free data globally. The LTAP has been one of the major advances/successes of the Landsat 7 mission in comparison to earlier Landsat missions. Although the LTAP is largely driven by cloud cover predicts, over the 50 states all data are acquired at all times regardless of cloud cover predictions, with the exception of high latitude winter scenes when there is inadequate solar illumination (e.g., Alaska). Even with the existence of the LTAP, special requests for specific coverage at specific times can be submitted to the Landsat data acquisition manager located at the USGS Center for Earth Resources Observation and Science (EROS). Such requests will be considered within the overall system constraints and a priority will be assigned to the request based on pre-existing guidelines – ranging from top priority/acquire at all costs (e.g., national emergency), to acquire if appropriate instrument duty cycle and on-board storage capacity exists. As a result of LTAP, a very rich archive of relatively cloud-free Landsat 7 ETM+ imagery exists within the data archive at the USGS EROS facility. custserv@usgs.gov
Satellite Instruments
3 Visible (30m), 2 NIR (30m), 1 MIR (30m), 1 Pan (15m), 1 Thermal (Low/High Gain)(60m) Global Mission, 350 scenes per day, SSR for international data acquisition Like the Landsat 4/5 TM, the ETM+ is an enhanced multi-spectral whisk-broom instrument that was developed and successfully launched by NASA as the only payload on the Landsat 7 satellite. The launch date for Landsat 7 was April 15, 1999. Lockheed-Martin (formerly General Electric) in Valley Forge, Pennsylvania built the spacecraft and the ETM+ instrument were designed and manufactured by Santa Barbara Remote Sensing (formerly Santa Barbara Research Center). The primary enhancements of the ETM+ over the TM are the addition of a 15 m panchromatic band, and a 4-fold improvement in the spatial resolution of the thermal IR band, band 6, from 120 m to 60 m. Enhanced instrument calibration capabilities were also incorporated into the design of the ETM+.
Rachel Headley
U.S. Geological Survey
USGS EROS Sioux Falls, SD 57198
Kristi Kline
U.S. Geological Survey
USGS EROS Sioux Falls, SD 57198
Measurment TypeVisible/IR-imager
Platform TypeLandsat 7
OrbitSun synchronous
Spectral Coverage
Scan PatternCross track
Repeat Time16
Wavelength0.45 to 12.5um
Number of Bands8
Start DateApr 1999
Temporal Coverage
Swath Width185 km
Resolution 130m
Resolution 260m
Resolution 315m
A Landsat special issue of Photogrammetric Engineering & Remote Sensing (PE&RS No. 72/10) was published in October 2006.
Scan Line Corrector failure occurred in May, 2003, causing 22% loss in scene pixels. Gaps can be filled with multiple acquisitions. In spite of the success and overall historical significance of the Landsat series of satellites dating back to July, 1972, the Landsat program has experienced continuous turmoil and unknowns when it has come to the funding and management oversight of each subsequent mission. In August 2004, Dr. John Marburger, Science Advisor to the President and Director of the Office of Science and Technology Policy (OSTP) at the White House issued a significant decision memorandum that stated “Landsat is a national asset, and its data have made – continue to make – important contributions to U.S. economic, environmental, and national security interests. Specifically, Landsat images are the principal source of global, medium resolution, spectral data used by Federal, state, and local government agencies, academia, and the private sector in land use / land cover change research, economic forecasting, disaster recovery and relief, and the scientific study of human impacts on the global environment. Additionally, Landsat data are utilized by over 70 countries and are an important part of a global, integrated Earth observation system.” He further stated that “In order to maintain Landsat’s legacy of continual, comprehensive coverage of the Earth’s surface, the U.S. … will transition the … program from a series of independently planned missions to a sustained operational program and establish a long-term plan for continuity of Landsat data observations.” It took about three years to solidify the concepts put forth back in August 2003, but on August 14, 2007 the following press release was issued by the Office of Science and Technology Policy: U.S. RELEASES PLAN FOR NATIONAL LAND IMAGING PROGRAM WASHINGTON--The Bush Administration today announced the release of a plan for a U.S. National Land Imaging Program. The plan will serve as the framework for continuing the collection of moderate resolution multispectral remote sensing data for the globe. The new Program would be established at the Department of the Interior and would provide focused leadership and management for the nation’s land imaging efforts. “This plan reflects President Bush's commitment to play a leadership role in understanding the changes in the land surface we observe across the world,” said John H. Marburger, Science Advisor to the President and Director of the Office of Science and Technology Policy. “The land surface, polar regions, and coastal zones are undergoing significant changes under the pressures of population growth, development, and climate change, and we must carefully monitor these changes in order to manage them. The importance of this imagery to the Nation requires a more sustainable effort to ensure that land imaging data are available far into the future.” The report presents a set of policy recommendations to achieve a stable and sustainable U.S. operational space-based land imaging capability and to ensure continued U.S. scientific, technological, and policy leadership in civil land imaging and the scientific disciplines it supports. The Plan calls for continued U.S. commitment to moderate-resolution land imagery, recommends the United States maintain a core operational capability for land imagery while supplementing its data with similar data from partners, and designates the Department of the Interior as the host of the program. The U.S. Landsat series of satellites has provided imagery of the entire Earth’s surface on a seasonal basis since it was begun in 1972. The data from Landsat are used for a wide variety of applications of land surface changes in land-use planning, agriculture, disaster reduction, water management, and analysis of human development. Currently, Landsat 5 and Landsat 7 are actively collecting data but are near the end of their functional lives. A successor to these satellites, the Landsat Data Continuity Mission, is scheduled to be launched in 2011. The creation of the National Land Imaging Program will ensure the availability of these key data far into the future. The new plan for a National Land Imaging Program will provide a mechanism within the Interior Department to assess the land imagery needs of federal agencies, state and local land management officials, scientists, and geographic researchers, and to translate those needs into the technical capabilities of future satellites. Responsibility for development, launch, and management of the long series of Landsat satellites has historically moved among agencies, and establishing the National Land Imaging Program will ensure a consistent planning and budgeting process for future land imaging missions. The plan was developed by the Future of Land Imaging Interagency Working Group (FLIIWG), an ad hoc group convened under the National Science and Technology Council, Committee on Environment and Natural Resources. The FLIIWG was comprised of fifteen agencies from seven Executive Branch departments. The work of the FLIIWG was conducted under the auspices of the U.S. Group on Earth Observations. For more information, including a copy of the plan, please visit: http://ostp.gov The future of Landsat data continuity is very promising. There are still details to be resolved, but the baseline importance of the data is set and a way forward has been developed and endorsed at the highest level of our government.
3 Sep 2009 13:47