Forest fire in the Boreal Region of China and its impact on the photochemical oxidant cycle of East Asia

A 3-D numerical investigation is carried out to assess the impact of a forest fire in northeastern China on the photochemical oxidant cycle of east Asia. Two simulations, without and with the emissions from the fire, are carried out during springtime in May 1987. The fire, located more towards the north, impacted the northern parts of Japan and the model domain, where an increase in ozone (5–10 ppb) is predicted for most of the second half of the month. A monthly averaged increase of 30% in the boundary layer ozone is predicted close to the fire source area. Our results indicate the influence of the fire on the tropospheric trace gas cycle over most of China, Japan and the Korean peninsula to be minimal, although an increase ( 40%) is predicted over Japan towards the end of the month. Favorable comparisons over the source region are obtained for the predicted column loadings due to the black carbon from the fire and the aerosol index from satellite measurements. On a monthly average basis, high values of the aerosol index (>1) and black carbon column loading (>20 mg m−2) are observed over the source regions.