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Nitrogen oxides in the global upper troposphere: interpreting cloud-sliced NO2 observations from the OMI satellite instrument

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journal contribution
posted on 30.04.2020, 15:59 by EA Marais, DJ Jacob, S Choi, J Joiner, M Belmonte-Rivas, RC Cohen, S Beirle, LT Murray, L Schiferl, V Shah, L Jaeglé

Nitrogen oxides (NOx≡NO+NO2) in the upper troposphere (UT) have a large impact on global tropospheric ozone and OH (the main atmospheric oxidant). New cloud-sliced observations of UT NO2 at 450–280 hPa (∼6–9 km) from the Ozone Monitoring Instrument (OMI) produced by NASA and the Royal Netherlands Meteorological Institute (KNMI) provide global coverage to test our understanding of the factors controlling UT NOx. We find that these products offer useful information when averaged over coarse scales (20∘×32∘, seasonal), and that the NASA product is more consistent with aircraft observations of UT NO2. Correlation with Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) satellite observations of lightning flash frequencies suggests that lightning is the dominant source of NOx to the upper troposphere except for extratropical latitudes in winter. The NO2 background in the absence of lightning is 10–20 pptv. We infer a global mean NOx yield of 280±80 moles per lightning flash, with no significant difference between the tropics and midlatitudes, and a global lightning NOx source of 5.9±1.7 Tg N a−1. There is indication that the NOx yield per flash increases with lightning flash footprint and with flash energy.

Funding

This work was funded by the NASA Tropospheric Chemistry Program and a University of Birmingham Research Fellowship and NERC/EPSRC grant (EP/R513465/1) awarded to Eloise A. Marais. Model simulations were performed on the University of Birmingham's BlueBEAR High-Performance Cluster (HPC). The authors would like to thank the BlueBEAR support team for IT and HPC support.

History

Citation

Atmospheric Chemistry and Physics Discussions, 18, 17017–17027, 2018

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Published in

Atmospheric Chemistry and Physics

Volume

18

Pagination

17017–17027

Publisher

European Geosciences Union (EGU), Copernicus Publications

eissn

1680-7375

Acceptance date

15/11/2018

Copyright date

2018

Available date

30/11/2018

Publisher version

https://www.atmos-chem-phys.net/18/17017/2018/

Language

en

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