HR: 09:15h
AN: AE21A-07    [Abstracts]
TI: Vertical Distribution of Nitrogen Oxides From Lightning Based on ECMWF Convective Mass Fluxes
AU: Olivie, D
EM: olivie@knmi.nl
AF: Royal Netherlands Meteorological Institute, P.O. Box 201, De Bilt, NL-3730 AE Netherlands
AU: * Meijer, E
EM: meijere@knmi.nl
AF: Royal Netherlands Meteorological Institute, P.O. Box 201, De Bilt, NL-3730 AE Netherlands
AU: van Velthoven, P
EM: velthove@knmi.nl
AF: Royal Netherlands Meteorological Institute, P.O. Box 201, De Bilt, NL-3730 AE Netherlands
AB: Most global chemistry transport models (CTMs) apply prescribed vertical profiles of lightning-produced nitrogen oxides (LNOx) based on a study by Pickering et al. (1998). However, these profiles are based on a few storm cases only, so their general applicability is uncertain and the models will likely have too little variability in the vertical distribution of LNOx. Furthermore it is difficult to incorporate these profiles consistently with other cloud parameters. In this study we suggest to vertically distribute LNOx according to the CTMs convective scheme, which is adopted from Tiedtke (1989). This new method involves the rescaling of the convective mass fluxes to the area of the storm, the separation of up- and downdrafts, and dealing with several complexities that arise when meteorological quantities are averaged over space and time. We will show that this convective redestribution of LNOx produces the expected C-shaped profiles, that are similar to those of Pickering, but with much larger variability, consistent with the variability of ECMWF convective vigour. Next we will evaluate these new LNOx profiles with lightning-influenced observations from EULINOX, conducted in Europa, and TROCCINOX, conducted in Brazil. The CTM used in this study is Tracer Model Version 4 (TM4) and is driven by meteorology of the European Centre for Medium-Range Weather Forecasts (ECWMF). The parameterization of LNOx is based on an empirical linear relationship between convective precipitation and flash frequency (Meijer et al., 2001).
DE: 3324 Lightning
DE: 3314 Convective processes
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0322 Constituent sources and sinks
SC: Atmospheric and Space Electricity [AE]
MN: 2004 AGU Fall Meeting