89th American Meteorological Society Annual Meeting

Tuesday, 13 January 2009: 1:30 PM
Variations in Large-Scale Circulation Affecting Extreme Hurricane-Generated Waves and Surges in the Gulf of Mexico
Room 126A (Phoenix Convention Center)
Donald T. Resio, ERDC, Vicksburg, MS; and E. A. Orelup and D. H. Levinson
It is shown here that large-scale sea level pressure (SLP) patterns within the subtropical and tropical Atlantic and average sea surface temperatures (SST's) within the Gulf of Mexico (GOM) play an important role in determining the number and intensity of storms occurring within the GOM. The temporal variability of storm characteristics related to these large scale features appears to invalidate some key assumptions used in conventional methods used to estimate extremes, the stationary Poisson behavior of hurricane frequencies and the independence of annual storm frequencies and intensities. Instead, it is shown that annual hurricane intensities and frequencies appear to be highly coupled, with years in which several storms occur producing an intensity distribution that is much stronger than years in which only 1 or 2 storms enter the Gulf of Mexico. The relationship between intensity and frequency means that it is essential to separate the hurricane population into separate populations when estimating extreme winds, surges and waves. The impact of this finding on estimated wind, wave and surge extremes within the Gulf of Mexico is also examined and found to be potentially significant.

Supplementary URL: