Convective redistribution of ozone and its precursors between the boundary layer (BL) and the free troposphere (FT) influences photochemistry, in particular in the middle and upper troposphere (UT). We present a case study of convective transport during the GABRIEL campaign over the tropical rain forest in Suriname in October 2005. During one measurement flight the inflow and outflow regions of a cumulonimbus cloud (Cb) have been characterized. We identified a distinct layer between 9 and 11 km altitude with enhanced mixing ratios of CO, O<sub>3</sub>, HO<sub>x</sub>, acetone and acetonitrile. The elevated O<sub>3</sub> contradicts the expectation that convective transport brings low-ozone air from the boundary layer to the outflow region. Entrainment of ozone-rich air is estimated to account for 62% (range: 33–91%) of the observed O<sub>3</sub>. Ozone is enhanced by only 5–6% by photochemical production in the outflow due to enhanced NO from lightning, based on model calculations using observations including the first reported HO<sub>x</sub> measurements over the tropical rainforest. The "excess" ozone in the outflow is most probably due to direct production by corona discharge associated with lightning. We deduce a production rate of 5.12 × 10<sup>28</sup> molecules O<sub>3</sub> flash<sup>−1</sup> (range: 9.89 × 10<sup>26</sup>–9.82 × 10<sup>28</sup> molecules O<sub>3</sub> flash<sup>−1</sup>), which is at the upper limit of the range reported previously.