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| Titel |
Aerosol indirect effect on the grid-scale clouds in the two-way coupled WRF–CMAQ: model description, development, evaluation and regional analysis |
| VerfasserIn |
S. Yu, R. Mathur, J. Pleim, D. Wong, R. Gilliam, K. Alapaty, C. Zhao, X. Liu |
| 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 ; 14, no. 20 ; Nr. 14, no. 20 (2014-10-24), S.11247-11285 |
| Datensatznummer |
250119120
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| Publikation (Nr.) |
 copernicus.org/acp-14-11247-2014.pdf |
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| Zusammenfassung |
| This study implemented first, second and glaciation aerosol indirect effects
(AIE) on resolved clouds in the two-way coupled Weather Research and
Forecasting Community Multiscale Air Quality (WRF–CMAQ) modeling system by
including parameterizations for both cloud drop and ice number concentrations
on the basis of CMAQ-predicted aerosol distributions and WRF meteorological
conditions. The performance of the newly developed WRF–CMAQ model, with
alternate Community Atmospheric Model (CAM) and Rapid Radiative Transfer
Model for GCMs (RRTMG) radiation schemes, was evaluated with observations
from the Clouds and the See http://ceres.larc.nasa.gov/.
Earth's Radiant Energy System (CERES) satellite and surface monitoring
networks (AQS, IMPROVE, CASTNET, STN, and PRISM) over the continental US
(CONUS) (12 km resolution) and eastern Texas (4 km resolution) during
August and September of 2006. The results at the Air Quality System (AQS)
surface sites show that in August, the normalized mean bias (NMB) values for
PM2.5 over the eastern US (EUS) and the western US (WUS) are 5.3%
(−0.1%) and 0.4% (−5.2%) for WRF–CMAQ/CAM
(WRF–CMAQ/RRTMG), respectively. The evaluation of PM2.5 chemical
composition reveals that in August, WRF–CMAQ/CAM (WRF–CMAQ/RRTMG)
consistently underestimated the observed SO42- by −23.0%
(−27.7%), −12.5% (−18.9%) and −7.9%
(−14.8%) over the EUS at the Clean Air Status Trends Network
(CASTNET), Interagency Monitoring of Protected Visual Environments (IMPROVE) and
Speciated Trends Network (STN) sites, respectively. Both configurations
(WRF–CMAQ/CAM, WRF–CMAQ/RRTMG) overestimated the observed mean organic
carbon (OC), elemental carbon (EC) and and total carbon (TC) concentrations
over the EUS in August at the IMPROVE sites. Both configurations generally
underestimated the cloud field (shortwave cloud forcing, SWCF) over the CONUS
in August due to the fact that the AIE on the subgrid convective clouds was
not considered when the model simulations were run at the 12 km resolution.
This is in agreement with the fact that both configurations captured SWCF and
longwave cloud forcing (LWCF) very well for the 4 km simulation over eastern
Texas, when all clouds were resolved by the finer resolution domain. The
simulations of WRF–CMAQ/CAM and WRF–CMAQ/RRTMG show dramatic improvements
for SWCF, LWCF, cloud optical depth (COD), cloud fractions and precipitation
over the ocean relative to those of WRF default cases in August. The model
performance in September is similar to that in August, except for a greater
overestimation of PM2.5 due to the overestimations of SO42-,
NH4+, NO3-, and TC over the EUS, less underestimation of
clouds (SWCF) over the land areas due to the lower SWCF values, and fewer
convective clouds in September. This work shows that inclusion of indirect
aerosol effect treatments in WRF–CMAQ represents a significant advancement
and milestone in air quality modeling and the development of integrated
emissions control strategies for air quality management and climate change
mitigation. |
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