@article{148301,
  author = {Denise L. Mauzerall and D. J. Jacob and S. M. Fan and J. D. Bradshaw and G. L. Gregory and G. W. Sachse and D. R. Blake},
  title = {Origin of Tropospheric Ozone at Remote High Northern Latitudes in Summer},
  abstract = { We quantify the tropospheric ozone budget over remote high northern latitudes in summer using chemical and meteorological measurements between 0 and 6-km made during the summer 1990 Arctic Boundary Layer Expedition (ABLE-3B). We include all components of the ozone budget, both sinks (in situ photochemical loss and deposition); and sources (in situ photochemical production, advection of pollution ozone into the region, production in biomass wildfire plumes, and downwards transport from the upper troposphere/stratosphere). In situ production and loss of ozone are calculated with a photochemical model. The net influx of pollution ozone from North America and Eurasia is estimated from the average enhancement ratio of DO<sub>3</sub>/DC<sub>2</sub>Cl<sub>4</sub>~observed in pollution plumes and scaled by the net influx of C<sub>2</sub>Cl<sub>4</sub>. The contribution of ozone produced in biomass wildfire plumes is estimated from the average enhancement ration of DO<sub>3</sub>/DCO in aged fire plumes. Regional photochemical production and loss in the 0-6 km column are found to be approximately equal; hence, net photochemical production is near zero. However, when ozone production and loss terms are separated, we find that dispersed in situ photochemical production driven by background NO<sub>x</sub>~levels (5-10 pptv) is the largest source term in the ozone budget (62\%). Influx of stratospheric ozone is of secondary importance (27\%), long-range transport of pollution ozone makes a small contribution (9\%), and photochemical production of ozone within biomass wildfire plumes is a relatively negligible term (2\%) in the budget. Biomass fires and transport of anthropogenic pollution in the region may however have a major effect on the ozone budget through enhancement of background NO<sub>x</sub>~mixing ratios which increase dispersed photochemical production. Using a 1-D time-dependent photochemical model between 0 and 6 km, we obtain good agreement between the observed and model-generated vertical ozone profiles. We find that in situ photochemistry within the 0-6 km column accounts for nearly 90\% of the ozone mixing ratio within the boundary layer, while above 5 km it accounts for only about 40\%. Although photochemical production of ozone within the 0-6 km column is larger than the other source terms combined, the 1-D model results indicate that influx from above is necessary to account for the observed increase in ozone mixing ratios with altitude. },
  year = {1996},
  journal = {Journal of Geophysical Research},
  volume = {101},
  pages = {4175-4188},
  language = {eng},
}