Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS)
The atmospherically corrected Landsat-5 data builds on previously work compiling a complete record of Landsat-5 scenes for LTER sites with less than 10% cloud cover. These images were converted to surface reflectance using the Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS http://code.google.com/p/ledaps/). The LEDAPS process convert Landsat data from digital numbers (DN) to corrected surface reflectance.
The LEDAPS project is hosted by the US Geological Survey (USGS) Earth Resources Observation and Science (EROS) Land Satellite Data Systems (LSDS) Science Research and Development (LSRD) Project.
Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) processes Landsat data from Level 1B (L1B) to surface reflectance using atmospheric correction routines similar to that developed for the MODIS instrument. This package includes three basic modules (plus a parameter parser and an internal cloud detection program) to convert Landsat data from digital numbers (DN) to surface reflectance. The three steps include:
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Calibrate digital number (DN) to top-of-atmosphere (TOA) reflectance.
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Correct to surface reflectance from TOA reflectance and ancillary data sets.
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Detect cloud pixels based on the surface reflectance.
The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) software was originally developed by the National Aeronautics and Space Administration-Goddard Space Flight Center and the University of Maryland to produce top-of-atmosphere reflectance from Landsat Thematic Mapper and Enhanced Thematic Mapper Plus Level 1 digital numbers and to apply atmospheric corrections to generate a surface-reflectance product. The U.S. Geological Survey (USGS) has adopted the LEDAPS algorithm for producing the Landsat Surface Reflectance Climate Data Record. The complete description is published as a PDF file and this report discusses the LEDAPS algorithm implemented by the USGS.
After conversion,each scene is packaged in a compressed tar file (*.tar.gz), which includes:surface reflectance (lndsr.*.hdf), top of atmosphere (TOA) reflectance (lndcal.*.hdf), and thermal brightness temperature (lndth.*.hdf). The data is organized by LTER site in the same manner as the original source data.
Contributors on this project include LTER scientists Tom Spies (PI), Zhiqiang Yang and Peder Nelson(programming and technical support), Theresa Valentine (logistics and coordination with LNO), Margaret O'Brien (EML support), Kyle Cavanaugh (technical advice), and LNO staff (John Vande Castle, Mark Servilla, and Duane Costa) for technical advice, EML generation, and PASTA integration.