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WAQS 2011b Modeling Platform


The 3SAQS project performed photochemical grid modeling (PGM) for the year 2011 using the Comprehensive Air Quality Model with Extensions (CAMx) version 6.20 and the Community Multiscale Air Quality (CMAQ) model version 5.0.2. The 3SAQS 2011 Modeling Protocol details the CAMx and CMAQ configurations and justification for why they were chosen for the WAQS. Version B of the WAQS base 2011 modeling platform (WAQS_Base11b) includes air quality modeling results for 36-km, 12-km, and 4-km modeling domains. The WAQS 2011b modeling platform includes a future projection year (2025) and CAMx source apportionment studies. The set-up and configuration of the WAQS 2011b platform was derived from the 3SAQS 2011 version A (3SAQS_CAMx_Base11a) modeling platform, but differs significantly in the input data used in the simulation. The link below provides a detailed description of the WAQS 2011b modeling platform:

CAMx two-way nested model configuration

The Western Air Quality Study (WAQS) conducted a CAMx 2011b base case simulation using a 36 km resolution CONUS, 12 km resolution WESTUS and 4 km resolution Intermountain West (i.e., CO, UT, WY and northern NM) modeling domains with two-way grid nesting. The CAMx 2011b 36/12/4 km base case simulation results are available on the Intermountain West Data Warehouse (IWDW) that includes model documentation, including a model performance evaluation. The modeling platform input and output files can be accessed through the IWDW Data Request Page, and a model-to-observation tool on the IWDW website allows users to compare and download paired PGM model output and observational data for specific monitor locations and time periods.

CAMx source apportionment modeling

Ozone and PM source apportionment (SA) modeling was also conducted using an “a” and “b” versions of the CAMx 2011 database with results available through a SA wiki on the IWDW that includes an interactive Source Apportionment Visualization Tool (SA Vis Tool). Several rounds of SA were performed, due to resource constraints the ozone SA modeling (Round 2, 2011b version) was performed on the 36/12 km CONUS/WESTUS domains and the PM SA modeling was conducted on the 36 km CONUS domains, thus the CAMx SA modeling results will not exactly match the CAMx 2011b 36/12/4 km base case modeling results because different domains were used. Even the WAQS Round 2 CAMx 2011b 36/12 km ozone SA modeling results for the 12 km domain will not match the CAMx 2011b 36/12/4 km base case 12 km results because the two-way nesting will replace the 12 km modeling results by the 4 km results in the CAMx 2011b 36/12/4 km base case simulation.



Air Quality Modeling