Interannual variability of tropospheric composition: the influence of changes in emissions, meteorology and clouds

We have run a chemistry transport model (CTM) to systematically examine the drivers of interannual variability of tropospheric composition during 1996–2000. This period was characterised by anomalous meteorological conditions associated with the strong El Niño of 1997–1998 and intense wildfires, whi...

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Main Authors: A. Voulgarakis, N. H. Savage, O. Wild, P. Braesicke, P. J. Young, G. D. Carver, J. A. Pyle
Format: Article
Language:English
Published: Copernicus Publications 2010-03-01
Series:Atmospheric Chemistry and Physics
Online Access:http://www.atmos-chem-phys.net/10/2491/2010/acp-10-2491-2010.pdf
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author A. Voulgarakis
N. H. Savage
O. Wild
P. Braesicke
P. J. Young
G. D. Carver
J. A. Pyle
author_facet A. Voulgarakis
N. H. Savage
O. Wild
P. Braesicke
P. J. Young
G. D. Carver
J. A. Pyle
author_sort A. Voulgarakis
collection DOAJ
description We have run a chemistry transport model (CTM) to systematically examine the drivers of interannual variability of tropospheric composition during 1996–2000. This period was characterised by anomalous meteorological conditions associated with the strong El Niño of 1997–1998 and intense wildfires, which produced a large amount of pollution. On a global scale, changing meteorology (winds, temperatures, humidity and clouds) is found to be the most important factor driving interannual variability of NO<sub>2</sub> and ozone on the timescales considered. Changes in stratosphere-troposphere exchange, which are largely driven by meteorological variability, are found to play a particularly important role in driving ozone changes. The strong influence of emissions on NO<sub>2</sub> and ozone interannual variability is largely confined to areas where intense biomass burning events occur. For CO, interannual variability is almost solely driven by emission changes, while for OH meteorology dominates, with the radiative influence of clouds being a very strong contributor. Through a simple attribution analysis for 1996–2000 we conclude that changing cloudiness drives 25% of the interannual variability of OH over Europe by affecting shortwave radiation. Over Indonesia this figure is as high as 71%. Changes in cloudiness contribute a small but non-negligible amount (up to 6%) to the interannual variability of ozone over Europe and Indonesia. This suggests that future assessments of trends in tropospheric oxidizing capacity should account for interannual variability in cloudiness, a factor neglected in many previous studies.
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spelling doaj.art-ad40bda07f9848ce88893139ea3a5d6a2022-12-22T02:46:19ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242010-03-0110524912506Interannual variability of tropospheric composition: the influence of changes in emissions, meteorology and cloudsA. VoulgarakisN. H. SavageO. WildP. BraesickeP. J. YoungG. D. CarverJ. A. PyleWe have run a chemistry transport model (CTM) to systematically examine the drivers of interannual variability of tropospheric composition during 1996–2000. This period was characterised by anomalous meteorological conditions associated with the strong El Niño of 1997–1998 and intense wildfires, which produced a large amount of pollution. On a global scale, changing meteorology (winds, temperatures, humidity and clouds) is found to be the most important factor driving interannual variability of NO<sub>2</sub> and ozone on the timescales considered. Changes in stratosphere-troposphere exchange, which are largely driven by meteorological variability, are found to play a particularly important role in driving ozone changes. The strong influence of emissions on NO<sub>2</sub> and ozone interannual variability is largely confined to areas where intense biomass burning events occur. For CO, interannual variability is almost solely driven by emission changes, while for OH meteorology dominates, with the radiative influence of clouds being a very strong contributor. Through a simple attribution analysis for 1996–2000 we conclude that changing cloudiness drives 25% of the interannual variability of OH over Europe by affecting shortwave radiation. Over Indonesia this figure is as high as 71%. Changes in cloudiness contribute a small but non-negligible amount (up to 6%) to the interannual variability of ozone over Europe and Indonesia. This suggests that future assessments of trends in tropospheric oxidizing capacity should account for interannual variability in cloudiness, a factor neglected in many previous studies.http://www.atmos-chem-phys.net/10/2491/2010/acp-10-2491-2010.pdf
spellingShingle A. Voulgarakis
N. H. Savage
O. Wild
P. Braesicke
P. J. Young
G. D. Carver
J. A. Pyle
Interannual variability of tropospheric composition: the influence of changes in emissions, meteorology and clouds
Atmospheric Chemistry and Physics
title Interannual variability of tropospheric composition: the influence of changes in emissions, meteorology and clouds
title_full Interannual variability of tropospheric composition: the influence of changes in emissions, meteorology and clouds
title_fullStr Interannual variability of tropospheric composition: the influence of changes in emissions, meteorology and clouds
title_full_unstemmed Interannual variability of tropospheric composition: the influence of changes in emissions, meteorology and clouds
title_short Interannual variability of tropospheric composition: the influence of changes in emissions, meteorology and clouds
title_sort interannual variability of tropospheric composition the influence of changes in emissions meteorology and clouds
url http://www.atmos-chem-phys.net/10/2491/2010/acp-10-2491-2010.pdf
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