HR: 0800h
AN: A21E-0781    [Abstracts]
TI: The influence of photolytic effects on modeled lightning-produced nitric oxides for the 10 July STERAO case
AU: * Ott, J
EM: jeremy.ott@hardrockers.sdsmt.edu
AF: Institute of Atmospheric Sciences, SD School of Mines & Technology 501 E. St. Joseph St., Rapid City, SD 57701-3995, United States
AU: Helsdon, J
EM: john.helsdon@sdsmt.edu
AF: Institute of Atmospheric Sciences, SD School of Mines & Technology 501 E. St. Joseph St., Rapid City, SD 57701-3995, United States
AU: Farley, R
EM: richard.farley@sdsmt.edu
AF: Institute of Atmospheric Sciences, SD School of Mines & Technology 501 E. St. Joseph St., Rapid City, SD 57701-3995, United States
AB: On July 10, 1996 a convective system developed in the late afternoon over the Cheyenne Ridge near the southern Wyoming-Nebraska border and was observed as part of the Stratospheric-Tropospheric Experiment: Radiation, Aerosols, and Ozone (STERAO) project. The cells moved in a south to southeastward direction crossing into northeastern Colorado before dissipation occurred in the evening hours. One of the main goals of STERAO was to investigate the role thunderstorms play in the redistribution of chemical species in the troposphere. A particular concern in the program was the distribution of odd nitrogen species; primarily focusing on NO_x (NO_x = NO + NO₂) production by lightning and the transport of NO_x into the troposphere and lower stratosphere based on the structure of the convective systems. We simulated this well documented storm with our three-dimensional Storm Electrification Model (SEM) with an explicit lightning scheme, which includes chemistry. The NO production is based on the energy dissipation of the lightning discharge including both a pressure dependence and a scheme that accounts for the cloud radiative effects on the chemical rate of photolytic reactions. This scheme is based on the actinic flux in the upper, middle, and lower portions of the thundercloud. The use of such a scheme allows for the effects of radiation transfer on the production of NOx from lightning. The chemical scheme incorporates nine chemical species, including NO, NO₂, O₃, CO, and CH₄. These chemical species take part in eighteen chemical reactions, which include three that are photolytic. We focus our simulations on the production of NO_x, with the goal of comparing the production based on three simulations: one with a clear sky photolytic scenario, another using the radiative transfer scheme, and the last scenario with the photolytic reactions turned off to simulate nighttime conditions. This modeling work is currently underway and the most recent results will be presented.
DE: 0320 Cloud physics and chemistry
DE: 0365 Troposphere: composition and chemistry
DE: 3304 Atmospheric electricity
DE: 3324 Lightning
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting