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| Titel |
WRF-CMAQ two-way coupled system with aerosol feedback: software development and preliminary results |
| VerfasserIn |
D. C. Wong, J. Pleim, R. Mathur, F. Binkowski, T. Otte, R. Gilliam, G. Pouliot, A. Xiu, J. O. Young, D. Kang |
| 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 ; 5, no. 2 ; Nr. 5, no. 2 (2012-03-12), S.299-312 |
| Datensatznummer |
250002443
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| Publikation (Nr.) |
 copernicus.org/gmd-5-299-2012.pdf |
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| Zusammenfassung |
| Air quality models such as the EPA Community Multiscale Air Quality (CMAQ)
require meteorological data as part of the input to drive the chemistry and
transport simulation. The Meteorology-Chemistry Interface Processor (MCIP)
is used to convert meteorological data into CMAQ-ready input. Key
shortcoming of such one-way coupling include: excessive temporal
interpolation of coarsely saved meteorological input and lack of feedback of
atmospheric pollutant loading on simulated dynamics. We have developed a
two-way coupled system to address these issues. A single source code
principle was used to construct this two-way coupling system so that CMAQ
can be consistently executed as a stand-alone model or part of the coupled
system without any code changes; this approach eliminates maintenance of
separate code versions for the coupled and uncoupled systems. The design
also provides the flexibility to permit users: (1) to adjust the call
frequency of WRF and CMAQ to balance the accuracy of the simulation versus
computational intensity of the system, and (2) to execute the two-way
coupling system with feedbacks to study the effect of gases and aerosols on
short wave radiation and subsequent simulated dynamics. Details on the
development and implementation of this two-way coupled system are provided.
When the coupled system is executed without radiative feedback,
computational time is virtually identical when using the Community
Atmospheric Model (CAM) radiation option and a slightly increased (~8.5%) when using the Rapid Radiative Transfer Model for GCMs
(RRTMG) radiation option in the coupled system compared to the
offline WRF-CMAQ system. Once the feedback mechanism is turned on, the
execution time increases only slightly with CAM but increases about 60%
with RRTMG due to the use of a more detailed Mie calculation in this
implementation of feedback mechanism. This two-way model with radiative
feedback shows noticeably reduced bias in simulated surface shortwave
radiation and 2-m temperatures as well improved correlation of simulated
ambient ozone and PM2.5 relative to observed values for a test case
with significant tropospheric aerosol loading from California wildfires. |
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