Development of a New Synthetic Hurricane Model for Deriving MetOcean Design Criteria for the Gulf of Mexico

Mudd, L. (Applied Research Associates) | Vickery, P. (Applied Research Associates) | Sarathi, P. (American International Group)

OnePetro 

Abstract

The objective of this work was to develop a robust methodology for deriving hurricane wind, wave, and storm surge design criteria for offshore structures in the Gulf of Mexico. The hurricane simulation model takes advantage of detailed historical database of Gulf of Mexico hurricanes, which includes detailed information on the characteristics of the wind field model not found in the HURDAT database. Using this new database, new statistical models were developed to describe the temporal changes in the storm size, the pressure–wind relationship and the correlation between storm size and intensity. The model includes features that enable the modeling of storm weakening and expansion of the wind field as a storm approaches the Gulf of Mexico coastline. A 1–dimensional ocean mixing model is coupled with an eddy model to enable the modeling of the interation between the simulated hurricanes and the warm eddies that break off from the loop current. A 100,000 year hurricane simulation was performed, the results of which can be used to form the basis for the development of the wind–wave–surge design criteria.

The synthetic hurricane model reproduces the Gulf of Mexico hurricane climate to a good degree, in terms of the distributions of storm size, intensity, and translation speed observed over the previous 50–100 years. In addition, the model provides more plausible values of rare (1,000 – year to 10,000 – year return period) winds as compared to extrapolations from the limited database of hindcast historical storms. This effort presents a step–change in the way hurricane criteria have traditionally been developed by industry. In moving to an extended hurricane database, derived from a synthetic model founded on the best modern hurricane data available, industry will benefit from more stable design criteria, and better estimates of rare return period site conditons.