Gulf of Mexico Hurricane Wave Heights
Authors: Bea R.G. 
Published: December 2007

Measurements of deep-water wave heights and winds generated by hurricanes in the Gulf of Mexico and inferred wave heights have been used to calibrate a hindcast model and to characterize its reliability. The model has been applied in a hindcast of deep-water maximum sea states generated by hurricanes that affected the area from 1900 through 1969.

Introduction

Since 1965, measurements have been made of deep-water wave heights and winds generated by severe hurricanes in the Gulf of Mexico. Platforms have provided additional data on maximum wave heights from damage sustained during hurricanes. These measurements and inferred wave heights were used to calibrate a hindcast model and characterize its reliability.

The calibrated model was applied in a hindcast of deep-water maximum sea states generated by major hurricanes that affected the Texas-Louisiana-Mississippi continental shelf from 1900 through 1969. The history of expected maximum wave heights at nine fictitious platform sites spaced 60 miles apart in 300 ft of water is platform sites spaced 60 miles apart in 300 ft of water is detailed. Wave-height measurements and observations used to calibrate and define hindcast reliability are given.

Background

The primary objective of this study was to provide background information required to select design criteria for bottom-supported drilling and production platforms. The methods, focus, and statistical characterizations were shaped by this objective.

The area studied is shown in Fig. 1. Nine fictitious platform sites (Sites a through j) in 300 ft of water were set platform sites (Sites a through j) in 300 ft of water were set up at 60-nautical-mile intervals along the edge of the continental shelf. These sites were the monitoring points for effects generated by major hurricanes affecting this area from 1900 through 1969.

The wave hindcast model used was developed by Wilson et al. The wind field model used was developed by Goodyear. The winds hindcast by this model were calibrated by Patterson, using wind measurements obtained in several hurricanes.

The hurricane's differential pressure (P) and radius to maximum winds (R) are used to describe a circulating wind field. This wind field is then moved along the path of the hurricane at the forward speed of the storm (VF). The components of the wind along given vectors to a site are used to generate wave heights at the site in a time-wise manner. In this way, each location builds a time history of sea states, expressed as height of the significant waves (Hs), from many different directions. The maximum sea state (Hs max) and its duration are obtained from such a site history.

A history can be developed on the maximum winds and their direction. Also, if a wind- and surge-driven current hindcast model is used, a history can be developed on the magnitude and direction of the currents. With a basic goal of deriving an environmental total-force characterization, a "model" platform can be placed at a site, and the history of combined forces caused by winds, waves, and currents can be detailed. The focus is on total force. In this manner, the problems of dealing with separate probabilities of wind, wave, and current, and their joint probabilities, are avoided.

Major emphasis in this paper is given to the expected maximum wave heights (He max) at the nine sites shown in Fig. 1.

JPT

P. 1160