Criss-crossing the world below at
nearly 17,000 miles per hour, NASA's Ice, Cloud and land Elevation
Satellite (ICESat) is providing scientists with revolutionary accuracy
and detail about the elevation of ice sheets and the elevation structure
of land surfaces. The principal objective of the ICESat mission, and its
Geoscience Laser Altimeter System (GLAS) instrument, is to measure the
surface elevations of the large ice sheets covering Antarctica and
Greenland and determine how they are changing. GLAS sends short pulses
of green and infrared light though the sky 40 times a second, all over
the globe, and collects the reflected laser light with a one-meter
telescope.
Much of an ice sheet's behavior and response to changes in climate are
apparent in their shape and how that shape changes with time. Gathering
such data from space will allow scientists to obtain an unprecedented
view of how and where ice sheets are growing and shrinking. This
information is critical to understanding how Earth's changing ice cover
affects sea level.
Although ICESat’s primary mission is to observe ice near the poles, the
satellite makes measurements continuously around the entire globe,
providing important information about Earth’s clouds, oceans, mountains,
forests and fields. For example, ICESat is providing scientists with the
most accurate measurements available of cloud heights and critical
observations of atmospheric particles called aerosol. Click
here to see an animation that shows the distribution of cloud layers
as seen from the bird’s-eye perspective of the ICESat spacecraft.
