Atmospheric Chemistry and Physics Discussions
www.atmos-chem-phys-discuss.net
1680-7367
1680-7375
5
6
2005
10.5194/acpd-5-11295-2005
http://www.atmos-chem-phys-discuss.net/5/11295/2005/
http://www.atmos-chem-phys-discuss.net/5/11295/2005/acpd-5-11295-2005.html
http://www.atmos-chem-phys-discuss.net/5/11295/2005/acpd-5-11295-2005.pdf
11295
11329
2005-11-09
Estimating the NO<sub>x</sub> produced by lightning from GOME and NLDN data: a case study in the Gulf of Mexico
S. Beirle
steffen.beirle@iup.uni-heidelberg.de
N. Spichtinger
A. Stohl
K. L. Cummins
T. Turner
D. Boccippio
O. R. Cooper
M. Wenig
M. Grzegorski
U. Platt
T. Wagner
Institut für Umweltphysik, Universität Heidelberg, Germany
Department of Ecology, Technical University of Munich, Germany
Norsk institutt for luftforskning NILU, Kjeller, Norway
Vaisala, Tucson, Arizona, USA
Global Hydrology and Climate Center, NASA Marshall Space Flight Center, Huntsville, Alabama, USA
NOAA Aeronomy Laboratory, Boulder, Colorado, USA
NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
Nitrogen oxides (NO<sub>x</sub>=NO+NO<sub>2</sub>) play an important role in
tropospheric chemistry, in particular in catalytic ozone production.
Lightning provides a natural source of nitrogen oxides, dominating the
production in the tropical upper troposphere, with strong impact on
tropospheric ozone and the atmosphere's oxidizing capacity. Recent estimates
of lightning produced NO<sub>x</sub> (LNO<sub>x</sub>) are of the order of 5 Tg [N] per
year with still high uncertainties in the range of one order of magnitude.
<br><br>
The Global Ozone Monitoring Experiment (GOME) on board the ESA-satellite
ERS-2 allows the retrieval of tropospheric vertical column densities (TVCDs)
of NO<sub>2</sub> on a global scale. Here we present the GOME NO<sub>2</sub> measurement
directly over a large convective system over the Gulf of Mexico.
Simultaneously, cloud-to-ground (CG) flashes are counted by the U.S.
National Lightning Detection Network (NLDN<sup>TM</sup>), and
extrapolated to include intra-cloud (IC)+CG flashes based on a
climatological IC:CG ratio derived from NASA's space-based lightning
sensors. A series of 14 GOME pixels shows largely enhanced TVCDs over thick
and high clouds, coinciding with strong lightning activity. The enhancements
can not be explained by transport of anthropogenic NO<sub>x</sub> and must be due
to fresh production of LNO<sub>x</sub>. A quantitative analysis, accounting in
particular for the visibility of LNO<sub>x</sub> from satellite, yields a
LNO<sub>x</sub> production of 77 (27–230) moles of NO<sub>x</sub>, or 1.1 (0.4–3.2) kg [N],
per flash. If simply extrapolated, this corresponds to a global
LNO<sub>x</sub> production of 1.5 (0.5–4.5) Tg [N]/yr.