In many parts of the world, wetlands are being converted to shrimp ponds
in order to farm these crustaceans for food and sale. One example is on
the west coast of Ecuador, south of Guayaquil. The 1991 Landsat image on
top shows a coastal area where 143 square kilometers of wetlands were
converted to shrimp ponds. By the time ASTER acquired the bottom image in
2001, 243 square kilometers had been converted, eliminating 83% of the
wetlands. These scenes cover an area of 30 x 31 km, and are centered near
3.4 degrees south latitude and 80.2 degrees west longitude.
With its 14 spectral bands from the visible to the thermal infrared
wavelength region, and its high spatial resolution of 15 to 90 meters
(about 50 to 300 feet), ASTER images Earth to map and monitor the changing
surface of our planet.
ASTER is one of five Earth-observing instruments launched December 18,
1999, on NASA's Terra satellite. The instrument was built by Japan's
Ministry of Economy, Trade and Industry. A joint U.S./Japan science team
is responsible for validation and calibration of the instrument and the
data products.
The broad spectral coverage and high spectral resolution of ASTER provides
scientists in numerous disciplines with critical information for surface
mapping, and monitoring of dynamic conditions and temporal change. Example
applications are: monitoring glacial advances and retreats; monitoring
potentially active volcanoes; identifying crop stress; determining cloud
morphology and physical properties; wetlands evaluation; thermal pollution
monitoring; coral reef degradation; surface temperature mapping of soils
and geology; and measuring surface heat balance.
The U.S. science team is located at NASA's Jet Propulsion Laboratory,
Pasadena, Calif. The Terra mission is part of NASA's Science Mission
Directorate.
Size: 30 by 31 kilometers (18.6 by 19.2 miles)
Location: 3.4 degrees South latitude, 80.2 degrees West longitude
Orientation: North at top
Image Data: Landsat bands 4,3 and 2; ASTER bands 3, 2, and 1
Original Data Resolution: Landsat 30 meters (24.6 feet); ASTER 15 meters (49.2 feet)
Dates Acquired: Landsat: April 29, 1991; ASTER March 31, 2001