P1.3

New perspectives on summertime UT/LS ozone over North America from the strategic IONS sounding network (2004, 2006)

Anne M. Thompson, Penn State Univ., University Park, PA; and J. C. Witte, S. J. Oltmans, O. R. Cooper, S. K. Miller, B. F. Taubman, J. E. Yorks, E. Joseph, J. T. Merrill, G. Morris, M. J. Newchurch, K. R. Minschwaner, M. K. Dubey, F. J. Schmidlin, D. W. Tarasick, B. Rappenglueck, B. Lefer, G. Forbes, D. Baumgardner, R. B. Chatfield, and R. B. Pierce

The recent deployment of strategically designed and launch-coordinated ozonesonde networks has revolutionized sampling in the UT/LS (upper troposphere-lower stratosphere) with consistent temporal and vertical (100 m) resolution. Examples include the SHADOZ (Southern Hemisphere Additional Ozonesondes) tropical network , operating since 1998, and the campaign-based IONS (INTEX [Intercontinental Transport Experiment] Ozonesonde Network Study) networks over North America in July-August 2004 and March-August 2006, . In IONS, spatial and temporal variations within a regionally dense network allow evaluation of ozone distributions and comparisons with correlative satellite data and models [Tarasick et al., 2007]. Ozone budgets throughout the UT/LS are determined in unprecedented detail. We present selected discoveries from the 2004 and 2006 IONS soundings:

• IONS provided ~300 O3 profiles from eleven North American sites and the R/V R H Brown in the Gulf of Maine. With July-August 2004 dominated by low- pressure conditions over northeastern North America (NENA), the UT/LS was a mixture of stratospheric O3 interleaved with O3 from aged or relatively fresh pollution and lightning. With a filtered version of the Pierce and Grant [1998] laminar technique, we find that > 1/4 of free tropospheric O3 in NENA originated in the stratosphere [Thompson et al., 2007a,b]. Analysis of potential vorticity and Wallops ozonesondes (38N, 75.5W) in June-July-August 1996-2004 suggests that stratospheric contribution to the 2004 UT/LS O3 budgets is typical.
• IONS in 2006 covered boreal spring and summer, with a greater range (the eleven 2004 sites plus a dozen in California, New Mexico, Mexico City, Barbados and southwestern Canada). There was more pollution in the troposphere and regional UT/LS O3 contrasts between 2004 and 2006 but both years displayed a persistent UT ozone maximum [Cooper et al., 2007] over the summertime south- central US. The March 2006 period over Mexico revealed distinct UT/LS gravity wave influence.

Poster Session 1, Chemistry and Dynamics of the Extratropical UTLS (Poster)
Tuesday, 21 August 2007, 1:30 PM-3:30 PM, Holladay

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