Hindcast of Winds, Waves and Currents in Northern Gulf of Mexico in Hurricane Lili (2002)

Abstract

Abstract The time varying fields of surface winds, sea state and currents associated with Hurricane Lili (2002) in the Northern Gulf of Mexico are specified through the implementation and application of advanced numerical wind, wave and ocean hindcast models, all adapted to the entire Gulf of Mexico at higher resolution than used in previous simulations of tropical cyclones in this basin. An extensive validation of the wind and wave hindcast indicates that the storm response is specified with 10% or better accuracy. No current measurements were available in Lili to validate the current model results but validation of the same modeling technology against the extensive currents measurements in Hurricane Andrew (1992) suggests that the spatial and vertical structure of the primary current speed response to Lili are reasonably well simulated. Introduction The objective of this study is to develop a comprehensive, definitive and reliable database of wind, sea state and currents associated with Hurricane Lili (2002) in the Northern Gulf of Mexico (GOM), through the implementation and application of advanced numerical wave and current hindcast models. The database is not only of intrinsic value, but also a critical element of the overall MMS program to investigate the impact of Lili on GOM offshore operations and infrastructure. In this sense the study and objectives are analogous to those of our comprehensive study of Hurricane Andrew (1,2). This study builds upon a virtual continuum of government and industry sponsored programs conducted over the past 35 years to measure, describe, understand and model the surface marine meteorological characteristics of GOM hurricanes and the corresponding ocean response to their passage. The most notable programs include the major measurement program and follow-up analysis phases of the 1969-1971 Ocean Data Gathering Program (ODGP) for winds and waves (3), the 1974-1977 Ocean Current Measurement Program (OCMP) for continental shelf currents, a number of Ocean Response to a Hurricane (ORHP) programs conducted during the 1980s (4) which utilized air-dropped current meters to measure mixed layer storm driven currents, and the aforementioned Hurricane Andrew study in 1994. The fruits of those programs have been integrated in major Joint Industry Projects (JIP) such as GUMSHOE (5) which has established the de-facto industry standard base of metocean design data in the northern GOM. Comparable studies have addressed the Bay of Campeche in the southwest GOM (6). While much of the JIP work has been proprietary, the underlying modeling and analysis methods have been documented and exposed to the scientific and engineering communities in the open literature. The data acquired in the ODGP provided a basis for the development and calibration of numerical models for the accurate specification of surface wind and wind stress fields in historical Gulf of Mexico hurricanes. Those models were the first to demonstrate that a numerical spectral ocean wave prediction model could be used to provide an accurate description of the complex pattern of sea states generated by and traveling with tropical cyclones (7).