Observations of ozone production in a dissipating tropical convective cell during TC4

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.