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Titel |
Analysis of ozone and nitric acid in spring and summer Arctic pollution using aircraft, ground-based, satellite observations and MOZART-4 model: source attribution and partitioning |
VerfasserIn |
C. Wespes, L. Emmons, D. P. Edwards, J. Hannigan, D. Hurtmans, M. Saunois, P.-F. Coheur, C. Clerbaux, M. T. Coffey, R. L. Batchelor, R. Lindenmaier, K. Strong, A. J. Weinheimer, J. B. Nowak, T. B. Ryerson, J. D. Crounse, P. O. Wennberg |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1680-7316
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 1 ; Nr. 12, no. 1 (2012-01-04), S.237-259 |
Datensatznummer |
250010432
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Publikation (Nr.) |
copernicus.org/acp-12-237-2012.pdf |
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Zusammenfassung |
In this paper, we analyze tropospheric O3 together with HNO3
during the POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface
Measurements and Models, of Climate, Chemistry, Aerosols, and Transport)
program, combining observations and model results. Aircraft observations
from the NASA ARCTAS (Arctic Research of the Composition of the Troposphere
from Aircraft and Satellites) and NOAA ARCPAC (Aerosol, Radiation and Cloud
Processes affecting Arctic Climate) campaigns during spring and summer of
2008 are used together with the Model for Ozone and Related Chemical
Tracers, version 4 (MOZART-4) to assist in the interpretation of the
observations in terms of the source attribution and transport of O3 and
HNO3 into the Arctic (north of 60° N). The MOZART-4 simulations
reproduce the aircraft observations generally well (within 15%), but some
discrepancies in the model are identified and discussed. The observed
correlation of O3 with HNO3 is exploited to evaluate the MOZART-4
model performance for different air mass types (fresh plumes, free
troposphere and stratospheric-contaminated air masses).
Based on model simulations of O3 and HNO3 tagged by source type
and region, we find that the anthropogenic pollution from the Northern
Hemisphere is the dominant source of O3 and HNO3 in the Arctic at
pressures greater than 400 hPa, and that the stratospheric influence is the
principal contribution at pressures less 400 hPa. During the summer, intense
Russian fire emissions contribute some amount to the tropospheric columns of
both gases over the American sector of the Arctic. North American fire
emissions (California and Canada) also show an important impact on
tropospheric ozone in the Arctic boundary layer.
Additional analysis of tropospheric O3 measurements from ground-based
FTIR and from the IASI satellite sounder made at the Eureka (Canada) and
Thule (Greenland) polar sites during POLARCAT has been performed using the
tagged contributions. It demonstrates the capability of these instruments
for observing pollution at northern high latitudes. Differences between
contributions from the sources to the tropospheric columns as measured by
FTIR and IASI are discussed in terms of vertical sensitivity associated with
these instruments. The first analysis of O3 tropospheric columns
observed by the IASI satellite instrument over the Arctic is also provided.
Despite its limited vertical sensitivity in the lowermost atmospheric
layers, we demonstrate that IASI is capable of detecting low-altitude
pollution transported into the Arctic with some limitations. |
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