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| Titel |
The global chemistry transport model TM5: description and evaluation of the tropospheric chemistry version 3.0 |
| VerfasserIn |
V. Huijnen, J. Williams, M. Weele, T. Noije, M. Krol, F. Dentener, A. Segers, S. Houweling, W. Peters, J. Laat, F. Boersma, P. Bergamaschi, P. Velthoven, P. Sager, H. Eskes, F. Alkemade, R. Scheele, P. Nédélec, H.-W. Pätz |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 3, no. 2 ; Nr. 3, no. 2 (2010-10-06), S.445-473 |
| Datensatznummer |
250000950
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| Publikation (Nr.) |
 copernicus.org/gmd-3-445-2010.pdf |
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| Zusammenfassung |
We present a comprehensive description and benchmark evaluation of the
tropospheric chemistry version of the global chemistry transport model TM5
(Tracer Model 5, version TM5-chem-v3.0). A full description is given
concerning the photochemical mechanism, the interaction with aerosol, the
treatment of the stratosphere, the wet and dry deposition parameterizations,
and the applied emissions. We evaluate the model against a suite of
ground-based, satellite, and aircraft measurements of components critical
for understanding global photochemistry for the year 2006.
The model exhibits a realistic oxidative capacity at a global scale. The
methane lifetime is ~8.9 years with an associated lifetime of methyl
chloroform of 5.86 years, which is similar to that derived using an
optimized hydroxyl radical field.
The seasonal cycle in observed carbon monoxide (CO) is well simulated at
different regions across the globe. In the Northern Hemisphere CO
concentrations are underestimated by about 20 ppbv in spring and 10 ppbv in
summer, which is related to missing chemistry and underestimated emissions
from higher hydrocarbons, as well as to uncertainties in the seasonal
variation of CO emissions. The model also captures the spatial and seasonal
variation in formaldehyde tropospheric columns as observed by SCIAMACHY.
Positive model biases over the Amazon and eastern United States point to
uncertainties in the isoprene emissions as well as its chemical breakdown.
Simulated tropospheric nitrogen dioxide columns correspond well to
observations from the Ozone Monitoring Instrument in terms of its seasonal
and spatial variability (with a global spatial correlation coefficient of
0.89), but TM5 fields are lower by 25–40%. This is consistent with
earlier studies pointing to a high bias of 0–30% in the OMI retrievals,
but uncertainties in the emission inventories have probably also contributed
to the discrepancy.
TM5 tropospheric nitrogen dioxide profiles are in good agreement (within
~0.1 ppbv) with in situ aircraft observations from the INTEX-B
campaign over (the Gulf of) Mexico.
The model reproduces the spatial and seasonal variation in background
surface ozone concentrations and tropospheric ozone profiles from the World
Ozone and Ultraviolet Radiation Data Centre to within 10 ppbv, but at
several tropical stations the model tends to underestimate ozone in the free
troposphere.
The presented model results benchmark the TM5 tropospheric chemistry
version, which is currently in use in several international cooperation
activities, and upon which future model improvements will take place. |
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