Analyses of Extreme Wave Heights in the Gulf of Mexico for Offshore Engineering Applications

Abstract

The 2004–2008 hurricane season in the Gulf of Mexico (GOM) saw several exceedances of what was regarded, prior to that period, as the 100-year significant wave heights (SWHs) that are used for the design of offshore oil and gas facilities. As a result, these facilities sustained considerable damage and disrupted U.S. energy supplies. The wave climatology in the GOM is therefore studied in detail. A 51-year database of SWHs was constructed by using a combination of wind and wave models, and both individual wave heights and statistical measures were validated, to the extent possible, using buoy data. Analyses of the modeled data show that there is an increasing trend in the annual maximum SWHs in the eastern part of the GOM; the maximum trend is approximately 5.6 cm/year, which is of the same magnitude as that reported for the U.S. west coast. The western part; on the other hand, shows a decreasing trend. The maximum estimated 100-year SWHs (denoted by SWH100) are 19.1 m, 22.6 m and 26.7 m for the Gumbel, Weibull, and the GEV distributions, respectively. The estimates obtained here using the Weibull distribution are comparable to those obtained independently by API (API—American Petroleum Institute, 2007, “Interim Guidance on Hurricane Conditions in the Gulf of Mexico,” API Bulletin No. 2INT-MET). However, the use of objective criteria to identify the optimal distribution suggests that the GEV estimates are to be preferred if the engineer wishes to emphasize the upper tail where extremes are likely to occur. The maximum increase in the SWH100 due to the 2004–2008 season is of the order of 0.9 m to 2.7 m (depending as the distribution). Information generated here is intended to supplement the design recommendations provided by API (American Petroleum Institute, 2007, “Interim Guidance on Hurricane Conditions in the Gulf of Mexico,” API Bulletin No. 2INT-MET).

A global ensemble of ocean wave climate projections from CMIP5-driven models

“…Wind-generated waves are recognized as a key element of the climate system 1 , having considerable environmental 2,3 , geophysical 3,4 and socioeconomic 5 impacts globally. They are considered paramount to navigation planning, offshore and coastal engineering activities, and energy generation (from fossil to renewable energy) 6 with structural design strongly dependent on wind-wave characteristics.…”

On the Use of Parametric Wind Models for Wind Wave Modeling under Tropical Cyclones

“…For instance, they are particularly useful to derive wind fields for long-term studies requiring modeling a large number of storms. Some examples of the use of parametric wind models include waves and storm surge analysis [32][33][34][35][36], wave setup estimation [37], risk modeling [38][39][40], forecasting [41,42], storm surge and waves hindcasting [43], emergency management [31], structural design [44], and analysis of trends under present climate and global warming [45,46].…”

Hurricane-induced waves and storm surge modeling for the Mexican coast

“…Historical events are commonly used to characterize such events, for instance Panchang et al (2013) uses of historical hurricanes to characterize extreme wave climate in the Gulf of Mexico while different authors have used historical records to characterize extreme events at specific locations (MezaPadilla et al under review;Wang and Oey 2008;Appendini et al 2014a, b). Nevertheless, historical data from tropical cyclones is sparse and may not constitute a representative dataset for doing extreme value analysis, leading to the generation of other databases, such as those by Vickery et al (2000) and Emanuel et al (2006).…”