Thompson, A.M., J.B. Stone, J.C. Witte, S.K. Miller, R.B. Pierce, R.B. Chatfield, S.J. Oltmans, O.R. Cooper, A.L. Loucks, B.F. Taubman, B.J. Johnson, E. Joseph, T.L. Kucsera, J.T. Merrill, G.A. Morris, S. Hersey, G. Forbes, M.J. Newchurch, F.J. Schmidlin, D.W. Tarasick, V. Thouret & J. Cammas. 2006. Intercontinental Chemical Transport Experiment Ozonesonde Network Study (IONS) 2004: 1. Summertime upper troposphere/lower stratosphere ozone over northeastern North America. Journal of Geophysical Research, 112, D12S12, doi:10.1029/2006JD007441.

Summary: Ozonesonde launches from the INTEX Ozonesonde Network Study (IONS) were conducted in July-August 2004. These launches were coordinated from eleven North American sites (including Sable Island), and from the NOAA vessel R/V Ronald H. Brown in the Gulf of Maine, and provided nearly 300 O₃ profiles. With the IONS period dominated by low-pressure conditions over northeastern North America, the free troposphere in that region was frequently enriched by stratospheric O₃. Stratospheric O₃ contributions to the region’s tropospheric O₃ budget were computed through analyses of O₃ laminae (Pierce & Grant 1998; Teitelbaum et al. 1996), tracers (potential vorticity and water vapor), and trajectories. This study demonstrated the lasting influence of stratospheric incursions into the troposphere, and found that the computed stratospheric contribution to tropospheric column O₃ over the R/V Ronald H. Brown and six sites in Michigan, Virginia, Maryland, Rhode Island, and Nova Scotia, 23% ± 3%, was similar to summertime budgets derived from European O₃ profiles (Collette & Ancellet 2005). Analysis of potential vorticity, Wallops ozonesondes (37.9°N, 75.5°W), and Measurements of Ozone by Airbus In-service Aircraft O₃ profiles for airports in northeastern North America during June through August 1996 to 2004 showed that the stratospheric fraction in 2004 may be typical. Boundary layer O₃ at Wallops and northeast USA sites during IONS also resembled O₃ climatology (June through August 1996 to 2003). However, statistical classification of Wallops O₃ profiles showed the frequency of profiles with background, nonpolluted boundary layer O₃ was greater than normal during IONS.