Using the Two-scale method to calibrate Rossby wave breaking statistics

Quantifying ozone flux across the dynamical tropopause, defined as a constant potential vorticity surface, poses significant challenges and questions about the nature of mixing at the mesoscale. The two-scale method, based on dividing the wind into 'mixing' and 'advective' components has been developed and tested in transport studies over East Asia. Here we present results of further investigation into the sensitivity of the diagnostic, as well as application to quantifying the ozone flux due to Rossby wave breaking (RWB) over the Pacific. Sensitivity of ozone flux to the following parameters is considered: the local Rossby radius, vertical scale separation, and the divergent/rotational wind ratio included in both the mixing and advective scales. Two particular applications of this method are shown. First, RWB over the Pacific is examined in order to understand mixing of Asian pollution and stratospheric air en route to North America. Second, the two scale method is used to quantify selected RWB events in distinct dynamical regimes. Calibration of RWB events with the two scale method will enable using our RWB climatology to estimate interannual variability of cross-tropopause ozone flux from long time series of meteorological analyses.