Abstract

Using the Weather Research and Forecasting Model with Chemistry (WRF/Chem) model, we conducted a series of numerical experiments to investigate the relative contributions of climate and emission change to surface ozone (O₃) over South China for the period of October in 2005-2007 and 2055-57. WRF/... Show moreUsing the Weather Research and Forecasting Model with Chemistry (WRF/Chem) model, we conducted a series of numerical experiments to investigate the relative contributions of climate and emission change to surface ozone (O₃) over South China for the period of October in 2005-2007 and 2055-57. WRF/Chem was driven by the outputs of Community Climate System Model version 3 (CCSM3). The simulations predict that on average near-surface temperature and water vapor mixing ratio are projected to increase 1.6 °C and 1.6 g kg⁻¹ under A1B scenario. In response to the climate change, the emissions of isoprene and monoterpenes in South China increase by 5-55% and 5-40%, respectively. The change of climate and biogenic emission can result in a change of -5 to 5 ppb of afternoon surface O₃ mixing ratios, with an average of 1.6 ppb over the land region in South China. Over Pearl River Delta, a region of dense network of cities, the 2000-2050 climate changes increase afternoon mean surface O₃ by 1.5 ppb. The change of anthropogenic emission can result in a change of -3-24 ppb of afternoon surface O₃ mixing ratios, with an average of 12.8 ppb over the land region in South China. Our analysis suggests that the anthropogenic emissions have greater impact on the change of surface O₃ concentration over South China compared to climate change. The combined effect of climate and emission can increase afternoon mean surface O₃ over South China by an average of 18.2 ppb in the land region, with the highest increase up to 24 ppb occurring over southeast of Hunan province. Show less