The Advanced Spaceborne Thermal Emission and Reflection radiometer, ASTER, is
an international project: the instrument was supplied by Japan's Ministry of
International Trade and Industry. A joint US/Japan science team developed
algorithms for science data products, and is validating instrument performance.
With its 14 spectral bands, extremely high spatial resolution, and 15 meter
along-track stereo capability, ASTER is the zoom lens of the Terra satellite. The
primary mission goals are to characterize the Earth's surface; and to monitor
dynamic events and processes that influence habitability at human scales.
ASTER's monitoring and mapping capabilities are illustrated by this series of
images of the San Francisco area. The visible and near infrared image reveals suspended sediment in the bays, vegetation health, and details of the urban environment.
Flying over San Francisco,
we see the downtown, and shadows of the large
buildings. Past the Golden Gate Bridge and Alcatraz Island, we cross San Pablo
Bay and enter Suisun Bay. Turning south, we fly over the Berkeley and Oakland
Hills. Large salt evaporation ponds come into view at the south end of San
Francisco Bay. We turn northward, and approach San Francisco Airport. Rather than
landing and ending our flight, we see this is as only the beginning of a 6 year
mission to better understand the habitability of the world on which we live.
Astronauts aboard the International Space Station (ISS) took this photograph of the San Francisco Bay area in April, 2002. The gray urban footprint of San Francisco, Oakland, San Jose, and their surrounding suburbs contrast strongly with the green hillsides. Of particular note are the Pacific Ocean water patterns that are highlighted in the sun glint. Sets of internal waves traveling east impinge on the coastline south of San Francisco. At the same time, fresher bay water flows out from the bay beneath the Golden Gate Bridge, creating a large plume traveling westward. Tidal current channels suggest the tidal flow deep in thebay. Because the ISS orbits are not synchronous with the sun, astronauts view the Earth with variable solar illumination angles. This allows them to document phenomena such as the sun reflecting differentially off surface waters in a way that outlines complicated water structures.
The Golden Gate of San Francisco Bay is one of the most recognizable straits in the world due to the Golden Gate Bridge that spans it. This high-resolution astronaut photograph is a nearly cloud-free view of the northern part of the San Francisco metropolitan area.