[1] We present case studies identifying lightning-generated upper tropospheric NO x (LNO x ) observed during NASA's Tropical Composition, Cloud and Climate Coupling Experiment (TC 4 ) in July and August 2007. In the campaign, DC-8 aircraft missions, flown from Costa Rica, recorded in situ NO 2 profiles near active storms and in relatively quiet areas. We combine these TC 4 DC-8 data with satellite data from the Ozone Monitoring Instrument (OMI) to estimate the lightning-generated NO 2 (LNO 2 ), above background levels, in the observed OMI NO 2 fields. We employ improved off-line processing techniques to customize the OMI retrieval for LNO 2 . Information on lightning flashes (primarily cloud-to-ground) observed by the Costa Rica Lightning Detection Network operated by the Instituto Costarricense de Electricidad and the World Wide Lightning Location Network were examined over storms upwind of regions where OMI indicates enhanced LNO 2 . These flash data are compared with Tropical Rainfall Measuring Mission/Lightning Imaging Sensor satellite data to estimate total flashes. Finally, using [NO x ]/[NO 2 ] ratios from NASA's Global Modeling Initiative model, we estimate LNO x production per flash for four cases and obtain rates of ∼100-250 mol/flash. These are consistent with rates derived from previous studies of tropical and subtropical storms and below those from modeling of observed midlatitude storms. In our study, environments with stronger anvil-level winds were associated with higher production rates. LIS flash footprint data for one of the low-LNO x production cases with weak upper tropospheric winds suggest below-average flash lengths for this storm. LNO x enhancements over background determined from the OMI data were in less than, but roughly proportional to, aircraft estimates.

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