Spatial variability in tropospheric peroxyacetyl nitrate in the tropics from infrared satellite observations in 2005 and 2006
Peroxyacetyl nitrate (PAN) plays a fundamental role in the global ozone budget and is the primary reservoir of tropospheric reactive nitrogen over much of the globe. However, large uncertainties exist in how surface emissions, transport and lightning affect the global distribution, particularly in t...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-05-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/17/6341/2017/acp-17-6341-2017.pdf |
| Summary: | Peroxyacetyl nitrate (PAN) plays a fundamental role in the
global ozone budget and is the primary reservoir of tropospheric reactive
nitrogen over much of the globe. However, large uncertainties exist in how
surface emissions, transport and lightning affect the global distribution,
particularly in the tropics. We present new satellite observations of free-tropospheric PAN in the tropics from the Aura Tropospheric Emission
Spectrometer. This dataset allows us to test expected spatiotemporal
distributions that have been predicted by models but previously not well
observed. We compare here with the GEOS-Chem model with updates specifically
for PAN. We observe an austral springtime maximum over the tropical Atlantic,
a feature that model predictions attribute primarily to lightning. Over
northern central Africa in December, observations show strong interannual
variability, despite low variation in fire emissions, that we attribute to
the combined effects of changes in biogenic emissions and lightning. We
observe small enhancements in free-tropospheric PAN corresponding to the
extreme burning event over Indonesia associated with the 2006 El Niño. |
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| ISSN: | 1680-7316 1680-7324 |