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| Titel |
Regional modelling of tracer transport by tropical convection – Part 1: Sensitivity to convection parameterization |
| VerfasserIn |
J. Arteta, V. Marecal, E. D. Rivière |
| 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 ; 9, no. 18 ; Nr. 9, no. 18 (2009-09-24), S.7081-7100 |
| Datensatznummer |
250007649
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| Publikation (Nr.) |
 copernicus.org/acp-9-7081-2009.pdf |
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| Zusammenfassung |
| The general objective of this series of papers is to evaluate long duration
limited area simulations with idealised tracers as a tool to assess tracer
transport in chemistry-transport models (CTMs). In this first paper, we
analyse the results of six simulations using different convection closures
and parameterizations. The simulations are using the Grell and
Dévényi (2002) mass-flux framework for the convection
parameterization with different closures (Grell = GR, Arakawa-Shubert = AS,
Kain-Fritch = KF, Low omega = LO, Moisture convergence = MC) and an ensemble
parameterization (EN) based on the other five closures. The simulations are
run for one month during the SCOUT-O3 field campaign lead from Darwin
(Australia). They have a 60 km horizontal resolution and a fine vertical
resolution in the upper troposphere/lower stratosphere. Meteorological
results are compared with satellite products, radiosoundings and SCOUT-O3
aircraft campaign data. They show that the model is generally in good
agreement with the measurements with less variability in the model. Except
for the precipitation field, the differences between the six simulations are
small on average with respect to the differences with the meteorological
observations. The comparison with TRMM rainrates shows that the six
parameterizations or closures have similar behaviour concerning convection
triggering times and locations. However, the 6 simulations provide two
different behaviours for rainfall values, with the EN, AS and KF
parameterizations (Group 1) modelling better rain fields than LO, MC and GR
(Group 2). The vertical distribution of tropospheric tracers is very
different for the two groups showing significantly more transport into the
TTL for Group 1 related to the larger average values of the upward
velocities. Nevertheless the low values for the Group 1 fluxes at and above
the cold point level indicate that the model does not simulate significant
overshooting. For stratospheric tracers, the differences between the two
groups are small indicating that the downward transport from the
stratosphere is more related to the turbulent mixing parameterization than
to the convection parameterization. |
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