1 **OTC CMAQ Air Quality Model Configuration Science Options**  **Configuration Details/Comments**  Model CMAQ Version 4.5 .1 Horizontal Grid Mesh 36km/12km 36 - km grid 145x102 cells 12 - km grid 172x172 cells Vertical Grid Mesh 22 Layers Grid Interaction One -way nesting Boundary Conditions GEOS - CHEM Emissions Baseline Emissions Processing SMOKE (Version 2.1) MM5 meteorology input to SMOKE & CMAQ Sub - grid- scale Plumes No Plume

–in- Grid (PinG) Chemistry Gas Phase Chemistry CBM - IV Aerosol Chemistry AE3/I SORROPIA Secondary

Organic Aerosols Secondary Organic Aerosol Model (SORGAM) Aerosol Mass Conservation Patch Yes Schell et. al., (2001) Cloud Chemistry RADM - ty pe aqueous chemistry In cludes sub - grid cloud processes N2 O 5 Reaction Probability 0.01 - 0.001 Meteorological Processor MCIP Version 3.0 Horizontal Transport Eddy Diffusivity

Scheme K- theory

with Kh grid size dependence Multi - scale Smagorinsky ( 1963) approach Vertical Transport Eddy Diffusivity

Scheme K- theory Diffusivity

L ower Limit Kzmin = 1.0 Planetary Boundary

L ayer No Patch Deposition Scheme M3dry Directl y linked to Pleim -Xiu Land Surface Model parameters Numerics Gas Phase Chemistry Solver Euler Backward

Iterative (EBI) solver Hertel et. Al. (1993) EBI solver ~2x

faster than MEBI Horizontal Advection Scheme Piecewise Parabolic

Method (PPM) scheme Simulation Periods 2002 Platform Linux Cluster2 **OTC MM5/SMOKE/CMAQ Modeling System Grid Configurations** OTC MM5/SMOKE/CMAQ modeling s ys tem for 2002 annual simulation is a pplied with a Lambert Conformal Conic projection with parallels at 33N and 45N. A spherical earth radius of 6370km is used in these programs. **MM5 Setup** MM5 was run with two - way nesting at 36 and 12km horizontal grid spacing and with 29 vertical layers. The top is at 50 mb. For 36km domain, the center is at 97W and 40N. There are 149 grids (dot- points) in east-west direction and 129 grids (dot-points) in north - south direction. The south -west corner is at ( - 2664km, - 2304km) and the north - east corner i s at (2664km, 2304km) For 12km domain, there are 175 grids in east-west direction and 175 grids in north - south direction. The south -west corner is at (252km, - 900km) and the north - east corner is at (2340km, 1188km) The 30 sigma - levels for the 29 vertical layers are: 1.0000, 0.9974, 0.9940, 0.9890, 0.9820, 0.9720, 0.9590, 0.9430, 0.9230, 0.8990, 0.8710, 0.8390, 0.8030, 0.7630, 0.7180, 0.6680, 0.6180, 0.5680, 0.5180, 0.4680, 0.4180, 0.3680, 0.3180, 0.2680, 0.2180, 0.1680, 0.1230, 0.0800, 0.0400, 0.0000 **C MAQ Setup**  CMAQ 36km modeling domain has 145 cells in east-west direction and 102 cells in north - south direction. The south -west corner is at ( - 2628km, - 1728km) and the north - east corner is at (2592km, 1944km) CMAQ 12km modeling domain has 172 cells in e ast-west directions and 172 cells in north- south direction. The south -west corner is at (264km, - 888km) and the north - east corner is at (2328km, 1176km) There are 22 vertical layers for CMAQ. The sigma- levels for these 22 layers are: 1.0000, 0.9974, 0. 9940, 0.9890, 0.9820, 0.9720, 0.9590, 0.9430, 0.9230, 0.8990, 0.8710, 0.8390, 0.8030, 0.7630, 0.7180, 0.6680, 0.5680, 0.4680, 0.3680, 0.2680, 0.1680, 0.0800, 0.0000 **SMOKE Setup** SMOKE modeling domains are same as CMAQ, except that the emissions are limited to the lower 16 CMAQ layers.3 **OTC Grid Definitions for MM5 and CMAQ** Model Columns

Dot (nx) Rows

Dot (ny) X - Origin

(km) Y - Origin

(km) MM5 36 - km 149 129 - 2664 - 2304 CMAQ 36 - km 145 102 - 2628 - 1728 MM5 12 - km 175 175 252 - 900 CMAQ 12 - km 172 172 264 - 8 88 **OTC Vertical Layer Definition for MM5 Simulations and Approach For Reducing**

**CMAQ Layers By Collapsing Multiple MM5 Layers MM5**  **CMAQ** Layer Sigma Pres(mb) Height(m) Depth(m) Layer Sigma Pres(mb) Height(m) Depth(m) 29 0.000 50 18600 2145 23 0.000 50 18 600 4290 28 0.040 88.5 16450 2145 27 0.080 127.1 14300 1460 21 0.080 127.1 14300 2920 26 0.123 168.5 12800 1460 25 0.168 211.8 11400 1200 20 0.168 211.8 11400 2390 24 0.218 260.0 10200 1200 23 0.268 308.1 8990 934 19 0.268 308.1 8990 1 870 22 0.318 356.3 8060 934 21 0.368 404.5 7120 772 18 0.368 404.5 7120 1540 20 0.418 452.6 6350 772 19 0.468 500.8 5580 662 17 0.468 500.8 5580 1320 18 0.518 549.0 4920 662 17 0.568 597.1 4250 581 16 0.568 597.1 4250 1160 16 0.618 64 5.3 3670 581 15 0.668 693.4 3090 532 15 0.668 693.4 3090 532 14 0.718 741.6 2560 455 14 0.781 741.6 2560 455 13 0.763 785.0 2110 388 13 0.763 785.0 2110 388 12 0.803 823.5 1720 337 12 0.803 823.5 1720 337 11 0.839 858.2 1380 290 11 0.839 858.2 13 80 290 10 0.871 889.0 1090 247 10 0.871 889.0 1090 247 9 0.899 916.0 844 207 9 0.899 916.0 844 207 8 0.923 939.1 637 169 8 0.923 939.1 637 169 7 0.943 958.3 468 133 7 0.943 958.3 468 133 6 0.959 973.7 334 107 6 0.959 973.7 334 107 5 0.972 986.3 227 8 2 5 0.972 986.3 227 82 4 0.982 995.9 145 57 4 0.982 995.9 145 57 3 0.989 1002.6 89 40 3 0.989 1002.6 89 40 2 0.994 1007.5 48 27 2 0.994 1007.5 48 27 1 0.9974 1010.7 21 21 1 0.9974 1010.7 21 21 0 1.000 1013.24 0 0 0 1.000 1013.24 0 0 Note: Layer-top pressures assume a surface pressure of 1013.24 hPa. Layer - top heights are determined by averaging MM5 (CMAQ) - calculated layer -top heights over time and space (the entire 172x172 domain).