The Status of Hurricane Forecasting and Its Significance to South Florida

Defense Date

7-23-2010

Document Type

Capstone

Degree Name

M.S. Coastal Zone Management

First Advisor

Richard Spieler

Second Advisor

Alexander Soloviev

Abstract

South Florida has experienced the most hurricane activity between 1926 and 2005. The state's population has also significantly grown since 1930. With the recent rise in hurricane activity, there is concern that the current status of hurricane forecasting may not be accurate enough to provide adequate lead time for evacuation.

During the historic 2005 hurricane season, Florida was hit by 3 hurricanes, with one of those a major hurricane. Official track and intensity forecast errors during 2005 at 48 hours were 106.4 nmi for track models, and 15.6 kt for intensity models. Official track and intensity errors at 36 hours were 84.2 nmi and 13.4 kt. These periods correspond to the notice times for a hurricane watch and warning.

Storm surge modeling is the least understood aspect of hurricane forecasting. The only available resource to the National Hurricane Center is the Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model is known to calculate surge levels which differ from observation by 20%. This error level has not changed and complicates the decision process for emergency officials.

There is a need for further observation of the inner shelf during a hurricane and the Acoustic Doppler Current Profiler (ADCP) has become a commonly used device in recent years. The broadband ADCP calculates a more precise estimate of current velocity than the narrowband ADCP. It transmits a series of small pulses within a larger pulse and computes the phase shift at the time interval separating consecutive pulses.

In order to measure the south Florida inner shelf circulation, it is necessary to correct the data for changes in sound speed and transmission loss. Sound speed is a function of pressure, temperature, and salinity. Transmission loss is typically referred to as the decline in signal intensity due to the combination of signal spreading and absorption. However, during high wind conditions, the presence of bubbles and elevated levels of suspended sediment concentrations (SSC) are also known to impact the transmitted signal.

The response of the south Florida inner shelf to hurricane David in 1979 was measured using current meters and water level and pressure sensors. The results are discussed in Smith (1982), and are summarized herein. In August of 1992, as hurricane Andrew struck south Florida, the inner shelf response was observed using current meters, and an ADCP. The results from the data are discussed in McLeish et al (1997) and will be summarized in this work. As hurricane Wilma passed over south Florida, a bottommoored broadband ADCP was in operation and its pressure, current components, and echo intensity data are included in this paper.

This document is currently not available here.


For NSU Patrons Only.

Share

COinS