12th Conference on Middle Atmosphere

Thursday, 7 November 2002: 4:50 PM
Quantifying cross-tropopause ozone flux over East Asia during TRACE-P
Marcus Lee BŁker, University of Wisconsin, Madison, WI; and M. H. Hitchman and R. B. Pierce
Operational regional simulations for the Transport of Aerosol and Chemistry Experiment in the western Pacific (TRACE-P) during March 2001 were performed with the University of Wisconsin Nonhydrostatic Modeling System (UWNMS). Forecasts of winds, temperatures, potential vorticity (PV), analytic 'pollution' tracers, and globally assimilated ozone fields (Pierce) were made available to the science team prior to each flight. On March 27th a higher resolution 24-hour simulation was performed and brought on the flight for nowcasting ozone (stratospheric) filament positions. Lidar data agreed very well in structure and position for all forecasted intrusions. It is known that small-scale processes irreversibly mix sheets of stratospheric air into the troposphere in the vicinity of synoptic storm systems. Since highly resolved pure advection (for inviscid, adiabatic flow) will cause the dynamical tropopause (defined by a selected PV isosurface) to move in tandem with an ozone isosurface, a two-scale method for analyzing ozone flux is implemented. This technique defines the tropopause with a smoothed PV field, while ozone is left highly resolved and the flux is calculated across the predetermined smoothed PV isosurface. These computed flux values are then compared with calculations from observed (in-situ and lidar) ozone values during the flights in regions of intrusions. The initial focus will be to determine accuracy and sensitivity to model resolution. An attempt is made to quantify the contribution of stratospheric ozone to total tropospheric amounts in the East Asian sector during spring.

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