June 30, 2006 By News Report
This new, second-generation Deep Ocean Assessment and Reporting of Tsunamis (DART II) system consists of pressure-sensitive tsunameters on the seafloor, and buoys on the ocean surface. The buoys are equipped with an acoustic modem that receives data from the tsunameter sensors and a small data modem to transmit the pressure measurements. The Iridium constellation of 66 low-earth orbiting (LEO) satellites transmits the pressure measurements to NOAA warning centers. Using this data, scientists can issue appropriate warnings to areas that may be affected.
Science Applications International Corporation (SAIC) is conducting testing and field service in the Pacific Ocean on the $37.5 million DART II system. NAL Research, an Iridium value-added manufacturer, is supplying the ruggedized Iridium data modems for the buoys.
"The DART II technology will make it easier and faster for warning centers to alert coastal areas in time to evacuate residents quickly," said Jack Rowley, SAIC DART manager. "The implications for saving lives are tremendous."
"The original DART I system, deployed in the late 1990s, used a high-power geostationary satellite for the data links, but the satellite's footprint limited its coverage to about a third of the Earth's surface," said Dr. Ngoc Hoang, president of NAL Research. "The DART II buoys, using Iridium technology, will provide complete global coverage."
The Iridium data link supports two-way data communications, permitting technicians at the warning centers to request tsunameter data from any specific buoy. For instance, the warning center may ask one or more buoys to transmit updates at a faster rate to improve real-time monitoring of a special area of interest.
"Enhancing our system with global monitoring capabilities supports our effort to facilitate widespread deployment of similar systems around the world," said Kathleen O'Neil, chief of operations branch, NOAA. "Other governments and agencies may be interested in building this tsunami detection capability in their own regions."