HR: 0800h
AN: A21C-0755    [Abstracts]
TI: Volatile Chemical Retention During Wet-growth Riming
AU: * Stuart, A L
EM: amystuart@tamu.edu
AF: Texas A&M University, 3150 TAMU, College Station, TX 77843-3150 United States
AU: Jacobson, M Z
EM: jacobson@stanford.edu
AF: Stanford University, Terman Engineering Center, Stanford, CA 94305-4020
AB: Interactions of chemicals with the ice phase in tropospheric clouds are poorly understood. Recent research indicates that volatile chemical partitioning during cloud hydrometeor freezing and riming may significantly impact cloud transport of soluble chemicals (e.g. HNO3, H2O2, SO2, aldehydes, and carboxylic acids) important to acid precipitation, the oxidizing capacity of the troposphere, and global climate change. In previous work, we have developed theory-based models and parameterizations of chemical partitioning during non-rime freezing and dry-growth riming. In this work, we develop a steady-state model for partitioning during wet-growth riming. Our model is adapted from a model used to predict the salinity of sea-spray ice and is based on solute mass and rate balances over a wet-growth riming hail particle. It accounts for drop impingement on the hydrometeor, hail growth, evaporation from hail, and shedding of liquid water. It also accounts for chemical partitioning between the water, air, and ice phases. Our model predicts that the retention efficiency (the ratio of a solute's mass in hail to that in the impinging supercooled drops) for wet-growth riming will be a function of the liquid water content of the hail, the solute effective Henry's law constant, the effective ice-water distribution coefficient, and the rates of impingement, growth, and shedding. Application of this model within cloud-scale convective storm simulations will help elucidate the impacts of cloud transport and processing on tropospheric chemistry.
DE: 3354 Precipitation (1854)
DE: 0320 Cloud physics and chemistry
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting