1 RAQMS-CMAQ Atmospheric Chemistry Model Data for the TexAQS-II Period : Focus on BCs impacts on air quality simulations Daewon Byun 1, Daegyun Lee 1, Hyuncheol Kim 1, Soontae Kim 1, Fong Ngan 1 ; Brad Pierce 2 ; Jassim Al-Saadi 3, Dorreen Neil 3 ; James Szykman 4 ; Todd Schaack 5 ; Chieko Kittaka 6 1 University of Houston, IMAQS; 2 NOAA/NESDIS; 3 NASA/Langley; 4 EPA/ORD; 5 University of Wisconsin; 6 Science Systems and Applications, Inc

2 Introduction   For the regional scale air quality simulations, boundary conditions are one of the most important inputs because they influence the temporal variations and spatial distributions of the pollutants.   One of the most common method to generate BCs inputs is utilization of global scale model outputs.   We have performed CMAQ simulations with three different BCs - Today’s results are preliminary Objective of the study 1. Assessment of boundary condition impacts on regional air quality simulations - BCs impacts on surface, middle and upper layers - Interactions between troposphere and lower stratosphere 2. Better simulations of regional air quality for the TexAQS II period, using boundary conditions generated from RAQMS which is fully assimilated with satellite data

3 Methodology : RAQMS-CMAQ 36km 12km 4km RAQMS : Global Chem/Aero Analysis - 2 degree longitude x 2 degree latitude - 35 vertical layers - Initialized with NOAA GFS Global Met. - Satellite data assimilation (MLS,TES, MODIS) CMAQ : Regional CTM - 36km – 12km – 4km domain - 23 vertical layers - MM5 w/ multiscale nest-down data assimilation - NEI TCEQ special inventory emission

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5 MM5/SMOKE/CMAQ Model Simulations ModelOptions MM5 EDAS (MADIS assimilated), USGS24, TFS LULC, Grell convection, RRTM radiation, MRF pbl, NOAH LSM SMOKE NEI 2002, Texas Special Inventory CMAQ CB4 (cb4_ae4_aq), PPM advection, Eddy vertical diffusion, RADM cloud   MM5 simulations are improved by multiscale nest-down data assimilation   Modeling period : ~   3 CMAQ simulations with different boundary conditions (BCON) (1) CMAQ predefined profile BCON (2) Typical year BCON (GEOS-Chem 2002 outputs without data assimilation) (3) BCON from fully data assimilated RAQMS outputs 36km 12km 4km

6 South East NorthWest Mean Ozone BCON from Profile, Typical year data, RAQMS w/ data assimilations South East NorthWest South East NorthWest   PF - Vertical variations only - Constant value at each levels   TY : Vertical/spatial variations   RAQMS - Strong spatial/vertical variations - High ozone values at the top layer 1.5 km 5 km 0 km 20 km 1.5 km 5 km 0 km 20 km

7 BCs effects on surface layer: 9/3/ (cst) BCs effects on Surface layer animation O3 diff. - Bndy cells: 20ppb - Inner cells: 2~4ppb

8 BCs effects on lower troposphere: 14 (1.5km) layer, 9/3/2006 O3 diff. - Bndy cells: 20ppb - Inner cells: 2~8ppb

9 BCs effects on middle troposphere: 18 (5~6 km) layer, 9/3/2006 O3 diff. - Over 30ppb

10 BCON effects on upper troposphere: 21 (12km) & Top layer 23 (20km) PFRAQMSTY TY-PFRQ-PF PFRAQMSTY TY-PFRQ-PF

11 “ What physical processes are important to bring down these upper-tropospheric high ozone anomaly to the surface level ? ”

12 Surface Weather chart 9/3~9/5/ :00 CST :00 CST :00 CST Frontal passage - -From Central USA including center of Texas state - -To Gulf of Mexico

13 500mb Weather chart 9/4~9/6/ :00 CST :00 CST :00 CST 500mb weather chart - -From :00 CST - -To :00 CST - -Every 12 hours animation

14 X & Y Cross section of ozone conc. at :00 CST 4 km

15 X & Y Cross section of ozone conc. at :00 CST 4 km

16 X & Y Cross section of ozone conc. at :00 CST 4 km

17 Comparison with ozonesonde profile

18 Summary of preliminary results Summary (1) CMAQ simulations with three different BCs (Profile, Typical Year, RAQMS) showed that the satellite data assimilated BC (RAQMS) impact model results throughout the layers (from top to surface layer) (2) With RAQMS BC, we could simulate the ozone intrusion from the stratosphere to the troposphere, showing the lower stratospheric ozone is entrained into the middle troposphere behind the cold front. - The effect reached down to 2.5km level Future work (1) CMAQ tracer mode simulation with 3 different boundary conditions to evaluate BCs impacts quantitatively. (2) Verification using various measurement data : - Ozonesonde, ground monitoring, aircraft data (3) Effects of long-range transported aerosols from the RAQMS BC, such as Saharan dust