Jan Kleissl and his colleagues at the University of California, San Diego, have developed a system that may be able to help farmers decide when to water their crops. The idea is to use lasers to detect the amount of moisture in the air above the crops, and to use this information to decide when they need to be watered. His system, known grandiosely as a "large-aperture scintillometer", consists of a laser on one side of a field, a telescope on the other, and a lot of computer power to work out how much the laser beam twinkles as it passes across the field.
Full story from The Economist Technology Quarterly.
SPIE Proceedings papers by Jan Kleissl.