ARL News

Extreme Turbulence Probes Successfully Deployed in Hurricane Frances

September 14, 2004

Three ARL scientists successfully placed three extreme turbulence (ET) spheres in Hurricane Frances. Rick Eckman, Ron Dobosy, and Tom Strong placed two spheres at Melborne Beach and one at Vero Beach, Florida. All equipment made it through the storm without damage and has been retrieved.

The ET spheres are part of a recent attempt to make detailed observations of important features of these storms as part of the U.S. Weather Research Program to reduce the nation’s vulnerability to hurricane landfall. Currently it is assumed that the major damage caused by any storm is not necessarily the average wind speed, but the gusts or turbulence. It is the turbulence that rips shingles and removes roofs from buildings. In addition, turbulent fluxes also determine whether the storm is strengthening or weakening. Turbulence measurements have not been made previously in hurricanes because no measurement instruments existed that could withstand the pounding of a hurricane. The successful ET sphere design is based on the robust and well proven pressure-sphere anemometer approach developed for the ill-fated Long-EZ research aircraft. Special considerations have been given to the need for stand-alone operation, ease of deployment, and resilience in high wind and heavy rain. Analysis of the data should provide turbulence structure and surface flux change at “ground zero” during hurricane landfall.

The team has been redeployed to set probes in advance of Hurricane Ivan.

Contact information: Kirk L. Clawson
Phone: (208) 526-2742