HR: 14:50h
AN: A43F-05    [Abstracts]
TI: Multiphase Modeling of Nitrate Photochemistry in the Quasi-Liquid Layer: Implications for NOx Release from the Arctic and coastal Antarctic Snowpack
AU: * Boxe, C S
EM: Christopher.Boxe@jpl.nasa.gov
AF: NASA-JPL, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AU: Saiz-Lopez, A
EM: Alfonso.Saiz-Lopez@jpl.nasa.gov
AF: NASA-JPL, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AB: We utilize a multiphase model, CON-AIR (Condense Phase to Air Transfer Model), to show that the photochemistry of nitrate ( ) in and on ice and snow surfaces, specifically the quasi-liquid layer (QLL), can account for the fluxes of gas phase NOx and the flux ratios measured above the Arctic and Antarctic snowpack. Maximum gas phase NOx fluxes and ratios simulated for spring and summer range from ~ 4.0 × 104 to ~ 5.0 × 105 molecules cm-3 s-1 and ~ 0.84 to 1.86, respectively. The model incorporates the appropriate actinic light spectrum, thereby properly weighting the different rates of photolysis of and . This is important since the immediate precursor for NO, for example, absorbs at wavelengths longer than nitrate itself. Finally, one-dimensional model simulations indicate that both gas phase and exhibit a negative concentration gradient as a function of height although [NO]:[NO2] are approximately constant.
DE: 0466 Modeling
DE: 0736 Snow (1827, 1863)
DE: 0738 Ice (1863)
DE: 1610 Atmosphere (0315, 0325)
DE: 1630 Impacts of global change (1225)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting