Healthy coral reefs sustain local and national economies through
fisheries, coastal protection, and tourism. Despite these benefits, it has
been estimated that 58 percent of coral reefs globally are threatened by
human activities (Bryant et al. 1998). Scientists still lack basic data
about the locations, spatial extent, and health of reefs. Major efforts
are underway in the U.S. and around the world to improve the mapping
information on coral reefs. Astronaut photographs are a unique data source
for these efforts because photos of the reefs have been collected for many
years, and the images are available in the public domain. Of particular
value is the fact that the astronauts took advantage of opportunities when
cloud cover was minimal to take the photographs. Astronaut photographs can
be used as primary data for maps of the locations of reef crests and as
supplemental data for use with other satellite images, especially when it
is important to distinguish small clouds from reef areas.
Astronaut photographs are being used as base maps in an international
compilation of information on coral reefs, known as ReefBase (http://www.reefbase.org/).
Images have also been included in a
prototype reef data distribution system that uses a global map based on 1.1-km
data from the SeaWiFS satellite sensor as a backbone for links to
georeferenced reef remote sensing data from a number of different
et al. 2000b) Investigations comparing the level of detail that can be
mapped from an astronaut photograph to that from other satellite data are
Astronaut photograph of Bahrain (STS078-748-11 combined with ReefBase data (yellow dot) and World Conservation Monitoring Centre maps of the reef crest (transparent red).
Images of the Tuamotu Archipelago, American Samoa, Malaysia, and the Philippines are targeted for acquisition during the Crew Earth Observations project, to provide additional data for these mapping investigations.
ReefBase text data for Fasht al Adhom, Bahrain.
|Subscribe to the
About the Earth Observatory
Please send comments or questions to: email@example.com
Responsible NASA official: Yoram Kaufman