Observations of ozone production in a dissipating tropical convective cell...

Morris, G. A., A. M. Thompson, K. Pickering, S. Chen, E. J. Bucsela, and P. A. Kucera (2010), Observations of ozone production in a dissipating tropical convective cell during TC4, Atmos. Chem. Phys., 10, 11189-11208, doi:10.5194/acp-10-11189-2010.

From 13 July–9 August 2007, 25 ozonesondes were launched from Las Tablas, Panama as part of the Tropical Composition, Cloud, and Climate Coupling (TC4) mission. On 5 August, a strong convective cell formed in the Gulf of Panama. World Wide Lightning Location Network (WWLLN) data indicated 563 flashes (09:00–17:00 UTC) in the Gulf. NO2 data from the Ozone Monitoring Instrument (OMI) show enhancements, suggesting lightning production of NOx . At 15:05 UTC, an ozonesonde ascended into the southern edge of the now dissipating convective cell as it moved west across the Azuero Peninsula. The balloon oscillated from 2.5–5.1 km five times (15:12–17:00 UTC), providing a unique examination of ozone (O3 ) photochemistry on the edge of a convective cell. Ozone increased at a rate of ∼1.6–4.6 ppbv/hr between the first and last ascent, resulting cell wide in an increase of ∼(2.1–2.5) × 106 moles of O3 . This estimate agrees to within a factor of two of our estimates of photochemical lightning O3 production from the WWLLN flashes, from the radar-inferred lightning flash data, and from the OMI NO2 data (∼1.2, ∼1.0, and ∼1.7 × 106 moles, respectively), though all estimates have large uncertainties. Examination of DC-8 in situ and lidar O3 data gathered around the Gulf that day suggests 70–97% of the O3 change occurred in 2.5–5.1 km layer. A photochemical box model initialized with nearby TC4 aircraft trace gas data suggests these O3 production rates are possible with our present understanding of photochemistry.

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Upper Atmosphere Research Program (UARP)