This March 3, 2000 image of the San Francisco Bay region shows a 60 by 75 kilometer Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image in band 1 (near infrared, 0.52-0.60 microns). The color coded suspended sediment image was created from band 1 by blacking out the land, and assigning colors to the relative brightnesses in the water. High values were colored white, then red, yellow, green, and blue. Brighter values in band 1 indicate higher sediment load in the water. The highest values are in Suisun and San Pablo Bays, into which the Sacramento River empties, and along the coast of the San Francisco Peninsula. The Pacific Ocean and San Francisco Bay water are relatively clear.
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.