Geoscience Reference
In-Depth Information
initial conditions, dry deposition algorithms, chemical mechanisms, and
other model configurations remained identical between September 1999
and 2007 simulations. The future case incorporated the 1999 base case
meteorology, and the model was run under varying levels of temperature
perturbations. The photochemical model grid system was in Lambert
conformal projection system centered at
100
◦
and 40
◦
with standard
parallel latitudes at 30
◦
and 60
◦
, respectively. The coarse outermost grid
of the photochemical modeling domain with a grid resolution of 36 km
covers south, southwest, and central parts of continental United States. The
inner grid of 12 km grid resolution envelops the urban centers of Houston-
Galveston area, Beaumont-Port Arthur area, Dallas-Fort Worth area,
and the eastern Texas region. The innermost grid of 4 km grid resolution
containing 90
−
108 cells is focused on south and central Texas and covers
all the urban areas including Austin, San Antonio, Victoria, and Corpus
Christi. The 12 vertical layers in CAMx extend from the surface all the way
up to 4 km.
The Emission Processing System version 2.0,
12
was utilized to process
emission inventory over the modeling domain and generate CAMx-ready
input gridded emission files. A report by ENVIRON,
13
contains the details
of the emissions inventory and emissions processing for the ozone episode
of September 1999. Table 1 highlights the emission loads for each of the
urban area in the south and central Texas.
Hourly meteorological data from 13-20 September 1999 were simulated
using Fifth Generation Pennsylvania State University/National Center of
Atmospheric Research (PSU/NCAR) Meteorological Model (MM5) version
4.3., as described by Grell
×
,
14
in a three-way nested grid mode to
produce gridded three-dimensional meteorological inputs needed for the
CAMx photochemical model. The meteorological model used analysis grid
et al.
Table 1. Emission loads (in tons) for urban areas of south and central
Texas during 13-20 September 1999.
NNA subdomain
Emissions (in tons)
Anthropogenic
Biogenic
NOx
VOC
NOx
VOC
Austin
1143
758
182
1862
San Antonio
1052
568
166
1560
Corpus Christi
1146
1393
323
329
Victoria
301
145
69
185
