Extended Abstract (84K)17A.5
Water recycling and water vapor transport in the vicinity of tropical cyclones from stable isotope ratios
James R. Lawrence, Univ. of Houston, Houston, TX; and S. D. Gedzelman
Water vapors in tropical cyclones have distinctly lower oxygen isotope ratios ( -14 to -26 per mil) than normal water vapor evaporated from the sea surface ( -9 to -12 per mil). These lower isotope ratios can be attributed to the storms' high condensation efficiency and the recycling of water as isotopic exchange occurs between inflowing vapor and falling rain. Water vapors analyzed for stable isotopes from numerous storms collected from multiple locations differ markedly from storm to storm reflecting differences in water recycling and transport of water vapor in the vicinity of the storm. Tropical Storm Gabrielle (1995) which moved very slowly westward across the Gulf of Mexico at 23.5 N into the Mexican coast produced low isotope ratios (-16 to -20 per mil) at collection sites 250 to 600 km to the north. In contrast to this Hurricane Dolly (1996, CAT 1) which moved very quickly across the Gulf of Mexico at 21.5 N into the Mexican coast produced near normal isotope ratios ( -11 to -14 per mil) at sites from 300 to 600 km north and one very low isotope ratio (-26 per mil) when the storm center was within 100 km of the collection site. Hurricane Luis ( 1995, CAT 4) which passed to the northeast of Puerto Rico produced normal isotope ratios (~ -10 per mil) until it reached within 300 km. Isotope ratios then decreased steadily to -18 per mil when the storm was 200 km north of the sampling site. Hurricane Danny (1997 CAT 1) moved slowly from SW to NE into the Alabama coast where it stalled in Mobile Bay. Vapors collected within 50 km of the storm center in the Mississippi delta area had oxygen isotope values of -15 per mil whereas vapors collected on the east side of Mobile Bay within 50 km of the center had values of -16 to -22 per mil. Hurricane Bonnie (1998, CAT 3 decreasing to CAT 1) produced slightly depressed isotope values (-11 to -15 per mil) when the center was more than 100 km away from the collection site but lower values (-17 to -19 per mil) as it passed directly overhead at New Bern.
Session 17A, Tropical Cyclone Observations and Structure VI(Parallel with Sessions 17B and 17C)
Friday, 3 May 2002, 11:00 AM-12:30 PM
Previous paper Next paper