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WRAP/WAQS 2014v1 Shake-Out Study


The objectives of the WRAP/WAQS 2014 Platform Development and Shake-Out Study (“Shake-Out Study”) is to develop regional photochemical grid model (PGM) modeling platforms for the western U.S. and 2014 calendar year using existing information. The Shake-Out Study 2014 PGM modeling platforms will be used for regional haze State Implementation Plans (SIPs) and potentially other air quality issues in the western states. The first two phases of the Shake-Out Study were performed during the first four months of 2019 and culminated in version 1 (2014v1) of the annual CMAQ and CAMx PGM 2014 base case simulations, model performance evaluation and documentation as described below.

2014v1 Shake-Out Study Modeling Plan

The initial draft Modeling Plan for the 2014 Shake-Out Study was dated December 31, 2018 and distributed to State, Federal and Local agencies who provided comments that were implemented in a second draft Modeling Plan that was also reviewed. The final 2014 Shake-Out Study Modeling Plan was dated March 9, 2019 and represented the implementation of two rounds of comments. The final Modeling Plan and Response-to-Comments documents can be found at the following links:

2014v1 Shake-Out Study Final Report

The 2014v1 Shake-Out Study Draft Final Report was dated May 21, 2019 and documents the first phases of the WRAP Shake-Out Study. The Draft Final Report provides details on the 2014v1 PGM platform development, sensitivity modeling for Boundary Conditions (BCs), meteorology and emissions and documents the final annual 2014v1 CMAQ and CAMx 36/12-km Shake-Out simulations and model performance evaluation. The draft final report can be found at the following link:

2014v1 PGM Platform Development

The existing information used to develop the 2014v1 Shake-Out Study PGM modeling platforms was primarily based on EPA’s 2014 PGM Modeling Platform and 2014 WRF meteorological modeling conducted by the Western Air Quality Study (WAQS).

2014 Meteorological Data

There are two existing 2014 Weather Research Forecast (WRF) meteorological model databases that were available for developing 2014 meteorological input for the two PGMs: (1) the EPA 2014 WRF 12-km database for the 12US2 continental U.S. domain; and (2) the WAQS 2014 36/12-km database for the 36-km 36US continental U.S. and 12-km 12WUS2 western U.S. modeling domains. Figure 1 displays the PGM modeling domains that were developed using the WAQS 36-km 36US and 12-km 12WUS2 and EPA 12-km 12US2 WRF data.

Figure 1. 36-km 36US, 12-km 12US2 and 12-km 12WUS2 modeling domains use in the 2014v1 Shake-Out PGM modeling.

The WAQS 12-km 12WUS2 and EPA 12-km 12US2 WRF output was evaluated against observed surface wind speed, wind direction, temperature and humidity (water mixing ratio) at surface monitoring sites in the western U.S. The WAQS and EPA WRF precipitation were evaluated against monthly and daily PRISM spatial maps in the western U.S. This resulted in 10s of thousands of WRF model evaluation graphical displays. The WAQS and EPA comparative model performance evaluation is summarized in Chapter 3 of the 2014v1 Shake-Out Draft Final Report and in a PDF that was presented to the RTOWG on a January 31, 2019 webinar. All WRF MPE graphical displays are available for viewing and download on the IWDW Website where the user can drill down and analyze the 2014 WRF MPE to individual states or even individual sites. There are three types of WAQS and EPA 2014 MPE products available: (1) soccer plots that display surface meteorological variability statistical performance measures against performance goals and criteria across all western states, within each western states and at individual monitoring sites; (2) time series plots of surface meteorological variable model performance; and (3) comparison of observed and predicted spatial plots of precipitation fields in the western U.S. by month and by individual day. Figures 2 and 3 displays example soccer and time series plots for the two 2014 WRF simulations and wind speed across the western U.S. An example of WRF performance against PRISM data for August monthly precipitation is shown in Figure 4.

ImageFigure title2. Example wind speed performance across western states for EPA (left) and WAQS (right) 2014 12-km WRF simulations.