These trailers are placed in the hurricane's path approximately 8 hours before impact, and the systems are then readied. After about 30 minutes of work, each trailer unfolds into a very stiff 10-meter tall tower able to withstand 200 MPH winds. Each tower is outfitted with multiple sensors at three elevations along its height. This equipment gathers wind speed and direction at 5 and 10-meter elevations as well as temperature, rainfall, barometric pressure, and relative humidity data. The equipment can be set to run for up to 24 hours, providing a detailed record of the storm's behavior as it approaches, passes over, and leaves the area.
All data is stored in digital form on two hard disks in the tower's computer system.
The units are operated at a sampling rate of 50 hertz, providing excellent resolution of high-speed wind field dynamics. The deployment of these mobile units is coordinated with the NOAA Hurricane Research Division. My team sends the GPS location of the towers to NOAA, which uses this information to arrange for GPS drop sondes to be dropped near the tower positions. These devices are dropped from hurricane hunter aircraft, and transmit wind information as they drift to the earth's surface. Subsequent analysis will allow correlation between the upper level winds and the surface wind speeds, thus providing, for the first time, a complete profile of wind characteristics from upper atmosphere to ground level.