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Ozone deposition to oceanic surfaces: biological impacts. Liz Coleman & Colin O Dowd. Parameterising Ozone Deposition. O 3 – link with iodine chemistry Deposition Velocity Wesely 89 Fairall 07 Turbulent / non turbulent regime Chemical enhancement term : a (s -1 ). AIR
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Ozone deposition to oceanic surfaces: biological impacts Liz Coleman & Colin O Dowd
Parameterising Ozone Deposition • O3 – link with iodine chemistry • Deposition Velocity • Wesely 89 • Fairall 07 • Turbulent / non turbulent regime • Chemical enhancement term : a (s-1) AIR LaminarSublayer Sea Wesely 89 Fairall 07 • Ra • Rb • Rc Rxa Rw
Turbulence & Reactivity Deposition Velocity Vs Reactivity For 10m wind-speeds 3 15 ms-1 15ms-1 12ms-1 9ms-1 6ms-1 3ms-1 U10=0.5ms-1
Scaling Reactivity: Iodide • REMOTE Region • 30°80°Latitude • NA Ocean: • 50° + • inferred max I- conc as 50nM • a=100s-1 • Min I- conc as 10 nM • a=20s-1 From Ganzeveld et al. 2008 using data from Truesdale 2000.
Scaling Reactivity: Organic Enhancement First Scaling attempt Clifford et al. 08 Chlorophyll=> Vd x 3
Results: Level 19, Noon, 15-05-03 [O3 in mg m-3] CF07 – max [I-] & Organic enhancement: a=100(1+[chfl]6.6) W89 CF07 – max [I-] a=100s-1
Results: Level 11, 6am 30-06-03 [O3 in mg m-3] CF07 – max [I-] & Organic enhancement: a=100(1+[chfl]6.6) CF07 – max [I-] a=100s-1 W89
Future Work • Iodide Concentrations • Temperature dependent reaction rate • Other reactions? • Further investigation to reactions of ozone with organic matter in seawater • Satellite chlorophyll readings as a surrogate representation of all ocean dwelling organic matter?
References W. Chang, B.G. Heikes and M. Lee. Ozone deposition to the sea surface: chemical enhancement and wind speed dependence. Atmospheric Environment 38:1053-1059, 2004. Daniel Clifford, D.J. Donaldson, Marcello Brigante, Barbra D’anna and Christian George. Reactive uptake of ozone by chlorophyll at aqueous surfaces. Environmental Science Technology, 42, 1138-1143, 2008. C.F. Fairall, D. Helmig, L. Ganzeveld, and J. Hare. Water-side turbulent enhancement of ozone deposition to the ocean. Atmos. Chem. Phys., 7:443-451, 2007 L. Ganzeveld, D. Helmig, C.W. Fairall and A. Pozzer. Atmosphere-ocean ozone exchange – a global modeling study of biogeochemical, atmospheric and water-side turbulence dependencies. 2008. L. Magi, F. Schweitzer, C. Pallares, P. Mirabel and C. George. Investigation of the uptake rate of ozone and methyl hydroperoxide by water surfaces. Journal of Geophysical Research, 101:4943-4949, 1997. V. W. Truesdale, A. J. Bale and E.M.S. Woodward. The meridional distribution of dissolved iodine in near-surface waters of the Atlantic ocean. Progress in Oceanography, 45:387-400, 2000. M. L. Wesely. Parameterization of surface resistances to gaseous dry deposition in regional-scale numerical models. Atmospheric Environment, 6:1293-1304, 1989