Environmental Engineering Reference
In-Depth Information
2. Participating Models and Simulation Setup
AURAMS is a multi-pollutant, regional air-quality modeling system with size
segregated and chemically speciated representation of aerosols (see Gong et al.,
2006; McKeen et al., 2007; Smyth et al., 2008). The AURAMS version 1.4 was
applied in a cascading fashion from 42 to 15 to 2.5-km resolutions, by one-way
nesting; the two coarser resolution runs (42 and 15 km) were carried out for the
entire ICARTT period (July 7-August 19, 2004) and the 2.5-km resolution case,
focused over the flight area, was run for August 10, 2004. The anthropogenic
emission files were prepared from the 2005 U.S. and Canadian and 1999 Mexican
inventories using version 2.3 of the SMOKE emission processing system (http://
www.smoke-model.org/index.cfm).
MesoNH:
The MesoNH model (Mesoscale Non-Hydrostatic atmospheric model)
was jointly developed by CNRM (Météo France) and Laboratoire d'Aérologie
(CNRS) (Lafore et al., 1998). MesoNH simulates small scale (LES type) to synoptic
scale and can be run in a two-way nested mode involving up to eight nesting stages.
Several parameterizations have been introduced and, in particular, for gaseous
chemistry (Tulet et al., 2003), aerosols chemistry (Tulet et al., 2006) and cloud
chemistry (Leriche et al., in preparation). Model runs at 15- and 2.5-km resolutions
in two-way nesting were carried out, the former from 12 Z August 9 to 0 Z August
11, 2004 and the latter from 0 Z August 10 to 0 Z August 11, 2004. The emission
input was prepared from a combination of POET and GEIA inventories at 1° × 1°
resolution.
WRF-CHEM:
The Weather Research and Forecasting (WRF) Chemistry model
is based upon the non-hydrostatic WRF community model developed at NCAR
(National Center for Atmospheric Research) in collaboration with several research
institutes and universities (http://www.wrf-model.org). Details of WRF/CHEM
can be found in Grell et al. (2005) and Fast et al. (2006). The simulations were
carried out using WRF/CHEM version 3.1 at 27-km resolution, for the eastern
U.S., from August 8 to August 10, 2004. WRF-CHEM simulations at 3-km resolution
are also being pursued. The emissions were prepared from the U.S. EPA 1999
National Emission Inventory with updated NOx and SO
2
emission rates from
selected U.S. power plants to their summer 2004 levels (Frost et al., 2006).
3. Results and Discussions
Modeled cloud processing of gases and aerosols depends critically on the ability to
predict cloud microphysics fields (Zhang et al., 2007). Modeled liquid water content
(LWC) is compared with the aircraft in-situ measurements sampled through
stratocumulus clouds along the two N-S lines. The models at high resolution (e.g.,
Fig. 1a,
GEM, AURAMS meteorological driver model, at 2.5 km) are able to
capture the observed spatial heterogeneity in LWC. The in-situ comparison
