HR: 0800h
AN: GC11A-0144    [Abstracts]
TI: Hurricane Wave Power Extremes Along the U.S. Atlantic and Gulf Coasts
AU: * Bromirski, P D
EM: pbromirski@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Drive, La Jolla, CA 92093-0209, United States
AU: Kossin, J P
EM: kossin@ssec.wisc.edu
AF: Cooperative Institute for Meteorological Satellite Studies, Univerity of Wisconsin-Madison, Madison, WI 94001, United States
AB: Extremes in wave power generated by tropical cyclones (TCs) will have an increasingly greater coastal impact as mean sea level rises. The Gulf 98th percentile (3 m) deep-water significant wave height, HS, measured at four open ocean NOAA buoys along the U.S. Atlantic coast and three Gulf buoys identifies extreme TC-generated wave events during the June-November hurricane season. Since 1978, there were substantially more significant HS events along the Atlantic coast than in the Gulf, with almost three times as many extreme wave events during September. The monthly distribution along both coasts peaks in September, with an equally likely chance of a significant TC wave event occurring during October as during August over the 1978-2006 data record. However, no clear trend in TC-generated extreme wave heights is observed. In general, the Atlantic buoys show a significant increase in seasonal wave power, PW, since 1995. PW during six of the hurricane seasons since 1995 exceeds all prior years at at least one of the Atlantic group buoys. In contrast to the Atlantic buoys, the Gulf buoys show exceptional seasonal PW levels only during the 2005 hurricane season when major Hurricanes Dennis, Emily, Katrina, Rita, and Wilma tracked trough the Gulf. The exceptional PW levels observed in the Gulf during 2005 were exceeded in the Atlantic during 1999, and approached during 1995 and 1996, attesting to a greater frequency of extreme TC-associated extreme wave events along the East Coast compared to the Gulf during the last four decades. A TC wave power index (WPI) increases significantly in the Atlantic during the mid-1990s, resulting largely from an increase in mid-to-late hurricane season TCs. The WPI is related to TC strength, size, duration, and frequency, and is highly correlated with the TC power dissipation index (PDI, Emanuel 2005). The close association of the WPI to hurricane activity implies that significant coastal impacts will increase as the PDI increases, regardless of TC landfall frequency. Differences between the Atlantic and Gulf WPI reflect systematic changes in TC genesis regions and subsequent tracks, characterized by their relationship with the regional circulation patterns described by the Atlantic Meridional Mode (Kossin and Vimont 2007).
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1630 Impacts of global change (1225)
DE: 1635 Oceans (1616, 3305, 4215, 4513)
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
DE: 4215 Climate and interannual variability (1616, 1635, 3305, 3309, 4513)
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting