HR: 0800h
AN: A11A-0844    [Abstracts]
TI: Alkyl Nitrate Saturation Anomalies in the tropical Pacific Ocean During PHASE-1
AU: Saltzman, E S
EM: esaltzma@uci.edu
AF: Department of Earth System Science, University of California at Irvine, 1212 Croul Hall, Irvine, CA 92697 United States
AU: * Dahl, E E
EM: edahl@esf.edu
AF: Department of Earth System Science, University of California at Irvine, 1212 Croul Hall, Irvine, CA 92697 United States
AU: Yvon-Lewis, S A
EM: syvon-lewis@ocean.tamu.edu
AF: Department of Oceanography, Texas A&M University, 3146 TAMU, College Station, TX 77843 United States
AB: The oceans are a major source of low molecular weight alkyl nitrates to the overlying marine atmosphere, but the oceanic source of these compounds is not well characterized. This study presents the first measurements of that saturation state of methyl, ethyl, and propyl nitrate in the Pacific Ocean. Simultaneous shipboard measurements of alkyl nitrates in air and air equilibrated with seawater were made in the tropical Pacific ocean during summer of 2004. Saturation anomalies (calculated as SA%=(ρ_sw-ρ_air)/ρ_air*100%) as high as 2000% (20-fold supersaturated) were observed, and the direction of the air/sea flux was uniformly out of the ocean. A simple steady state box model was used to examine the relationship between oceanic and atmospheric alkyl nitrates. The observed surface ocean alkyl nitrates can account for tropospheric levels, but the estimated atmospheric loss rates due to photolysis and OH reaction are not sufficient to maintain the high observed saturation states. The implication is that removal via transport must be important, and there is likely a net export of alkyl nitrates out of the tropics into other regions of the atmosphere.
DE: 0312 Air/sea constituent fluxes (3339, 4504)
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0365 Troposphere: composition and chemistry
DE: 0469 Nitrogen cycling
DE: 4820 Gases
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005