P2.15
The impact of lightning NOx production on atmospheric chemistry in a CRYSTAL-FACE thunderstorm simulated using a 3-D cloud-scale chemical transport model
L. Ott, Department of Meteorology, University of Maryland, College Park, MD; and K. Pickering, G. Stenchikov, R. -. F. Lin, B. Ridley, M. Loewenstein, J. Lopez, and E. Richard
As part of the Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE), a number of thunderstorms were observed in July, 2002, by research aircraft. Observations of cloud-to-ground (CG) lightning were available from the National Lightning Detection Network (NLDN) for the project's duration. Estimates of intracloud (IC) flashes were made based on a combination of climatological IC/CG ratios and deviations from average weak positive flash rates. Selected CRYSTAL-FACE storms were simulated using the PSU/NCAR mesoscale model (MM5) in cloud-resolving mode with a horizontal resolution of 2 km. Output fields from the MM5 were used to drive an offline cloud scale chemical transport model (CSCTM) developed at the University of Maryland which employs a photochemical ozone mechanism. Flashrates derived from NLDN observations were used to generate a parameterized lightning NOx source in the CSCTM. An estimate of NOx production per lightning flash was obtained by comparing in situ anvil chemical observations with model results. The effect of lightning produced NOx on ozone and other species was analyzed by comparing a simulation including lightning NOx production with a simulation which did not include a source of lightning NOx. In order to estimate the effects of lightning NOx on downstream ozone production in the 24 hours following the convection, a chemistry-only version of the CSCTM was employed.
Poster Session 2, Poster Session 2
Tuesday, 11 January 2005, 9:45 AM-11:00 AM
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