Thompson, A.M., J.B. Stone, J.C. Witte, S.K. Miller, S.J. Oltmans, T.L. Kucsera, K.L. Ross, K.E. Pickering, J.T. Merrill, G. Forbes, D.W. Tarasick, E. Joseph, F.J. Schmidlin, W.W. McMillan, J. Warner, ,E.J. Hintsa & J.E. Johnson. 2006. Intercontinental Chemical Transport Experiment Ozonesonde Network Study (IONS) 2004: 2. Tropospheric ozone budgets and variability over northeastern North America. Journal of Geophysical Research, 112, D12S13, doi:10.1029/2006JD007670.

Summary: During 2004, July 7th to August 11th, daily ozone soundings were taken from the NOAA vessel R/V Ronald H. Brown as part of the INTEX Ozonesonde Network Study (IONS). The study investigated the vertical structure of ozone over the Gulf of Maine and characterized variability in sources of tropospheric ozone (i.e. stratosphere, regional convection and lightning, advection, and local boundary layer pollution). These soundings were part of a network of twelve IONS stations that launched ozonesonde-radiosonde instruments over the USA and maritime Canada during the INTEX/International Consortium for Atmospheric Research on Transport and Transformation (ICARTT)/New England Air Quality Study project, July 1st to August 15th, 2004. Four of the IONS stations were in mid-Atlantic and northeast USA, and four were in southeastern Canada (and included Sable Island). Although the goal was to examine pollution influences under stable high-pressure systems, during the study northeastern North America was dominated by weak frontal systems that mixed aged pollution and stratospheric ozone with ozone from more recent pollution and lightning. These sources were quantified to provide tropospheric ozone budgets for individual soundings that are consistent with tracers and meteorological analyses. On average, for stations in northeastern North America during July-August 2004, tropospheric ozone was composed of 10–15% local boundary layer, 10–15% regional sources (includes that related to lightning-derived nitric oxide), and 20–25% stratospheric ozone. The balance was a mixture of recently advected ozone and aged air of indeterminate origin.