Radar paints land with colors of life.

An experimental radar flying aboard the space shuttle Endeavour bounced microwaves off the forests of Michigan's Upper Peninsula this week, enabling scientists to map vegetation just emerging from a long winter. The new radar--the most sophisticated yet to fly on the shuttle--uses three different microwave frequencies to probe Earth's surface. Besides mapping plant life, the device can provide information about soil moisture, rock type, and even ocean currents. NASA built the instrument in collaboration with the German and Italian space agencies.

With data beamed down from the shuttle, researchers at the University of Michigan in Ann Arbor created two images depicting the amount and type of vegetation in a 15-by 20-mile region around Raco Air Force Base, near the southeast shore of Lake Superior. In the left map, red, orange, yellow, green, and purple hues indicate increasing amounts of biomass. In the right image, white areas represent flat, unvegetated surfaces such as water, ice-covered lakes, and bare soil. Grasses and shrubs appear in red, deciduous trees in yellow, and conifers in green and purple.

Radar images such as these can help scientists assess environmental changes, whether caused by human actions or by natural processes, according to NASA. Unlike space-borne cameras, this instrument can "see" through clouds an at night. The radar will fly on another shuttle mission in August, enabling investigators to compare how regions change between seasons.