MIT and the Army are working together to modify 45 existing FAA (Federal Aviation Agency) weather Doppler radar sites around the country so that they can detect and track cloud plumes from a chemical or biological event. Five of the radars will be modified and in operation by the end of the year. The Homeland Defense Chemical Biological Umbrella has been allocated $15 million and has the ultimate goal of covering three dozen cities. The FCC Doppler radar system is designed to detect hazardous wind sheer conditions threatening aircraft during takeoff and landing, but backers are confident enhanced computer software will be able to differentiate between typical weather patterns around aircraft and a chemical or biological release. Once detected, a cloud's movement can be tracked to assist emergency response efforts.

Skeptics aren't sure if the techniques will be accurate enough to differentiate between a legitimate threat and simple dust and pollution, generating false alarms for such conditions as high pollen or smog days. However, the Army has already tested the ability of Doppler radar to track substances released into the air. In 2003, initial characterization tests over Oklahoma fields used grain alcohol, clay dust, and a mix of water and antifreeze released by a plane. Final tests are scheduled this month with an independently evaluated demonstration tentatively scheduled for late May or June. The Doppler system would most likely be used in combination with other sensors. Doug Mohney