HR: 15:25h
AN: B23F-08    [Abstracts]
TI: The Availability of Cloud-free Landsat ETM+ Data Over the Conterminous U.S. and Globally
AU: * Ju, J
EM: junchang.ju@sdstate.edu
AF: GIScience Center of Excellence, South Dakota State University, 1021 Medary Ave, Box 506B, Brookings, SD 57007, United States
AU: Roy, D P
EM: david.roy@sdstate.edu
AF: GIScience Center of Excellence, South Dakota State University, 1021 Medary Ave, Box 506B, Brookings, SD 57007, United States
AB: This research evaluates the availability of cloud-free ETM+ data over the conterminous U.S. and globally, specific to broad terrestrial remote sensing application requirements, including obtaining at least one cloud-free ETM+ observation in a year, a season, and two different seasons, or at least a pair of cloud-free observations no more than 16, 32, 48, 64, and 80 days apart within a year or a season. Probabilities of obtaining cloud-free observations are derived by analysis of three years of USGS Landsat Project ETM+ cloud fraction metadata (a total of 236,000 records for 2000-2002). Spatially explicit probability maps and summary statistics are presented. The results are relatively stable across the three years. Over the conterminous U.S., where every Landsat scene is acquired by the Landsat project, applications requiring at least one cloud-free observation in a year, a season, two different seasons, or at least two cloud-free observations occurring even within a 16-day period in a year, are largely unaffected by cloud cover (mean probabilities of cloud-free data availability > 0.94), except for certain Winter applications and cloudy scenes near the U.S.-Canada border and the Great Lakes. Cloud becomes a constraint for U.S. applications when at least two cloud-free observations within a season are required. Globally, only land applications requiring at least one cloud-free observation per year are largely unaffected by cloud cover and the reduced global ETM+ acquisition frequency; all the other application requirements considered are severely affected. The implications of these results for the development of new approaches to mitigating cloud contamination in the USGS ETM+ data archive and the global acquisition rate for the future Landsat Data Continuity Mission are discussed.
DE: 0480 Remote sensing
SC: Biogeosciences [B]
MN: 2007 Fall Meeting