HR: 1340h
AN: A53B-1143    [Abstracts]
TI: 1-D Air-snowpack Modeling of Atmospheric Nitrous Acid (HONO) during ANTCI 2003
AU: Liao, W
EM: lliaowei@gatech.edu
AF: Georgia Institute of Technology, 311 Ferst Drive, Atlanta, Ga 30332,
AU: * Tan, D
EM: lliaowei@gatech.edu
AF: Georgia Institute of Technology, 311 Ferst Drive, Atlanta, Ga 30332,
AB: HONO measurements in ambient air during ANTCI (Antarctic troposphere chemistry investigation) 2003 exceed the pure gas phase model predictions by a factor of 1.92(plus/minus 0.67), which implies snow emission of HONO. A 1D air-snowpack model of HONO was developed and constrained by observed chemistry and meteorology data. The 1D model includes pure gas phase chemical mechanisms, molecular diffusion and mechanical dispersion, windpumping in snow, gas phase to quasi-liquid layer phase HONO transfer and quasi- liquid layer (QLL) nitrate photolysis. Dominant snowpack HONO sources include QLL nitrite in equilibrium with firn air deep below the snow surface and snowpack nitrate photolysis. The high concentration of HONO in the firn air is subsequently transported above the snowpack by diffusion and windpumping. The primary model uncertainties include the pH and volume of the QLL and snowpack nitrite concentration profiles.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0317 Chemical kinetic and photochemical properties
DE: 0322 Constituent sources and sinks
DE: 0360 Radiation: transmission and scattering
DE: 0365 Troposphere: composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting