A detailed evaluation of the WRF-CMAQ forecast model performance for O 3, and PM 2.5 during the 2006 TexAQS/GoMACCS study Shaocai Yu $, Rohit Mathur +, Daiwen Kang $, Jonathan Pleim +, Daniel Tong $, Brian Eder + and Kenneth Schere + Atmospheric Sciences Modeling Division NERL, U.S. EPA, RTP, NC $ On assignment from Science and Technology Corporation + On assignment from Air Resources Laboratory, NOAA

Introduction

CMAQC ommunity M ultiscale A ir Q uality M odel Community Model Multiscale – consistent model structures for interaction of urban through Continental scales Multi-pollutant – ozone, speciated particulate matter, visibility, acid deposition and air toxics

grid cells 259 grid cells Northeast “1x” Domain East “3x” Domain Testing Domain: Summer 2006 Testing Domain: Summer 2006 Experimental: CONUS “5X” 442 grid cells 265 grid cells Operational: EUS “3x” CONUS “5x” Domain This Study

Tracks of ship Tracks of P-3 flights

 Results: Operational evaluation for O 3 at AIRNOW sites  overprediction (8/25-9/30)  Very low O 3 concentrations Obs Model  Underprediction: high conc. range

 Results: Operational evaluation for PM 2.5 at AIRNOW sites due to underestimation of SO 4 2-, NH 4 + (see later) Obs 11.7±7. 9 Mod9.9±6.6 Obs11.7±7.9 Mod9.9±6.6  Mean:  Underpredicted obs PM 2.5 by 16%  Significant underprediction (8/1-8/31)

 Results: Time-series evaluation with ship  Gas species O3Model37.82 Obs35.04 NO2Model11.07 Obs6.14 NOyModel15.91 Obs10.28 COModel Obs SO2Model2.11 Obs3.32 ISOPModel0.23 Obs0.28 HCHOModel2.39 Obs1.82 TOLModel0.30 Obs0.50 ALDModel2.02 Obs1.07 over Gulf of Mexico

 Meteorological parameters  Results: Time-series evaluation with ship data  Model underestimated SO 4 2-, NH 4 +, NO 3 - by -29, -41, -86%, respectively over Gulf of Mexico TempObs28.9 Model28.7 WDIR10Obs167.4 Model164.3 WSPD10Obs3.6 Model3.9 RGRNDObs461.8 Model466.2 Mean

 Results ( PM 2.5 SO 4 2-, NH 4 + ): vertical profiles  Over predicted SO 4 2- aloft but under prediction at surface  CB-4 chemical mechanism produces too much H2O2 (Yu et al., 2007) Layer means for model and observations from the aircraft (P 3 ) during the 2006 TexAQS/GoMACCS  The model under predicted NH 4 + both at the surface and aloft, Daily Layer Means

 Results ( Vertical profiles for O 3,CO and SO 2 ) Daily Layer Means SO 2 :  Close to obs at high altitude  Higher than obs at low altitude O 3 :  good at low altitude  Overprediction at high altitudes CO:  good at low altitude  Under-prediction at high altitudes

Daily Layer Means  Results ( Vertical profiles for NOy, NO2 and NO ) NOy, NO 2, NO and HNO 3 :  Generally good at high altitudes  Overprediction at low altitudes

Acetaldehyde:  overprediction Daily Layer Means Toluene, Isoprene:  underestimation  Results ( Vertical profiles of VOC species )

Site 1 ( Washington, D.C.)  Results: Time-series evaluation at PAMS sites

 Results: summary at 4 sites and all 9 PAMS sites site1234Total O3Obs Model NMB COObs Model NMB NOObs Model NMB NO2Obs Model NMB NOxObs Model NMB SO2Obs Model NMB

Contacts: Brian K. Eder

Contacts: Brian K. Eder

Site 2  Results: Time-series evaluation at PAMS sites

 Results : Total sulfur during 2004 ICARTT  Results (preliminary) : Time-series evaluation at PAMS sites Obs4.6±5 NMM5.9±4 ARW6.8±5  Mean  SO 2 : very scatter, over-predict low conc. but under-predict high conc.

 Results : O 3 Vertical profiles Sulfur Dioxide 2002 Summer 12-km Eastern US  Results: Standard CMAQ performance for SO 2