A Hurricane Outlook for the 21st Century.

Transcription

1 A Hurricane Outlook for the 21st Century. Hugh Willoughby Florida International University Cat Winds Effects One mph No real damage to building structures. Two Three Four Five mph mph mph > 155 mph Saffir-Simpson Scale Some roofing material, door, and window damage to buildings. Considerable damage to vegetation, mobile homes, and piers. Some structural damage to small residences and utility buildings with a minor amount of curtainwall failures. Mobile homes are destroyed. More extensive curtainwall failures with some complete roof structure failure on small residences. Major erosion of beach. Major damage to lower floors of structures near the shore. Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. Major hurricanes, CAT 3-5, cause 80% of US damage Institute for Supply Management, Mid-Winter Conference, Las Vegas, NV, 23FEB Memorable Hurricanes of 2005 Gulf of Mexico Hurricanes of 2005 Hurricane Dates Damage Deaths Dennis (4) 4-13 JUL $2B 3 Katrina (5) 23-31AUG $80B 1200 Rita (5) 17-26SEP $9.4B 6 Wilma (5) 15-25OCT $14B Hurricane Records in 2005 Earliest CAT 4 hurricane since Audrey in 1957 Greatest season-total US damage ~ $105B Greatest US hurricane loss of life since 1928 ~1200 Most named storms: 26 (19 in 1995 or 22 in 1933) Most hurricanes: 14 (12 in 1969) Tie for most major hurricanes: 7 (1950) Most major hurricane landfalls: 4 (3 in 1909,1933,1954) Most CAT 5 hurricanes: 3 (2 in 1960 & 1961) Lowest western-hemisphere sea-level pressure, 882 mb in Wilma (888 in Gilbert in 1988) Three of the seven most intense hurricanes on record ---Wilma, Rita and Katrina---[Allen (1980), Camille(1969), the Labor-Day Hurricane of 1935 and Gilbert (1988)] North Atlantic TCs by Year North Atlantic Tropical Cyclones 5 6

2 Great Ocean Conveyor Belt Everybody wants a view like this 7 8 Inflation-Adjusted Damage, Normalized Hurricane Damage Pielke & Landsea (1998) Corrects for: Inflation Population increase Greater personal wealth What would historical hurricanes cost with 2005 population and development? Constant at $5B per year, Normalized Hurricane Damage Hurricane Deaths Corrected to $105B Only four catastrophic seasons : 1972, 1979, 1989 & 1992 Note the respite from hurricanes

3 A Role for Global Warming? Hurricanes are heat engines that draw energy from the tropical ocean Knutson & Tuleya (2004)---numerical study with 2 x CO 2 environment Found strongest hurricanes become 5-6 m/s stronger and rain 25% more, but no increase in numbers Emanuel (2005) found increased hurricane energy dissipation since early 1970s in climatological records Webster et al. (2005) found more CAT 4 & 5 worldwide, but no increase in total numbers. Potential problems with satellite intensity estimates, pressure-wind relation, and other aspects of the---generally sparse---data 13 What do you meteorology folks really think about all this global warming stuff, anyway? 14 It s reasonable that there was some effect, but it wasn t the dominant factor in Hurricane Triangle The 1999 Hurricane Season 1999 Hurricane Season 17 18

4 2004 Hurricane Season Gulf of Mexico Hurricanes of Tropical Cyclone Eye in Environmental Shear Rita 1445UT 21Sep05 Rita 21 Most hurricanes do not reach their maximum potential intensity because of shear, narrowness and high latitude of the Atlantic, or storm-induced cooling of the sea. 22 Gulf of Mexico Ocean Heat Content Emanuel Cycle GoM Ocean Heat Content 23 24

5 Role of the Loop Current The Nightmare Scenario Comes to Pass 25 Katrina s Landfall in New Orleans 26 weatherunderground Levees failed in CAT 1 conditions Storm-Surge Devastation on the Gulf Coast Summary respite from devastating hurricanes. Four devastating Gulf of Mexico hurricanes in 2005: Dennis, Katrina, Rita & Wilma Low shear and tracks over the Loop Current produced rapid deepening to CAT 4 or 5 But all were CAT 2 or 3 at landfall, Only Wilma was intensifying---slowly. Failure of the canal dikes in CAT 1 conditions was responsible for > 1000 deaths in Katrina Roles of natural cycles, chance, or anthropogenic global warming? Increasing coastal population and development. Expect more hurricanes! 29 Thank you for your attention. Questions? 30