2007 Volume 3 Pages 133-136
We evaluated the ability of a regional air quality (AQ) model, the Weather Research and Forecast chemistry (WRF/Chem), to reproduce vertical profiles of summertime ozone (O3) pollution over the Kanto region of Japan using lidar-observed O3 data collected over Tsukuba on 27-29 July and 16-21 August 2005. WRF/Chem well reproduced the high O3 concentrations > 2.5 × 1018 molec. m-3 (∼100 ppbv below 1.5 km above sea level ASL) observed on 28 July and 20 August, and the low concentrations on the other days below 1.5 km ASL, as well as day-to-day variations above 1.5 km ASL. The formation mechanism of the observed O3 layer in the typical northward transport case on 28 July was also examined by the model. The O3 plumes entered the free troposphere through vertical transport and mixing near the sea breeze front and southward transport by the return flow in the afternoon. In the evening, the O3 layer formed at 0.7-1.5 km ASL possibly because of less transport between the sea breeze and return flow and longer photochemical lifetime than at the surface.
