1. Wang Jiandong 1, Wang Shuxiao 1, Zhao Bin 1, Wang Long 1, David Wong 2, Jonathan Pleim 2, Hao Jiming 1 1. Tsinghua University, Beijing, China 2. U.S. EPA, NC, USA Interactions between Particulate Matter and Meteorology: a Modeling Study Using Two-way CMAQ in China

2. Interaction Between Particulate Matter and Meteorology IPCC AR5, 2013.

3. Interaction Between Particulate Matter and Meteorology Ding, A. J. et al, ACPD, 2013

4. Two-way Model Introduction D.C. Wong et al, Geosci. Model Dev, 2012

5. Model Configuration Simulation System  WRFV3.3/CMAQ5.0 Mechanism  Land surface mechanism: PL-X  Radiation mechanism: rrtmg/cam  Gas-phase/aerosol CB05&AERO6 modeling domain  China Horizontal Resolution:  36km×36km Vertical layers  23 layers Time Period:  December 2010 Scenario 1  Without feedback (NF) Scenario 2  Feedback by using RRTMG Scenario 3  Feedback by using CAM

6. Inventory SO 2 NO X 2010 (t/km 2 ) PM 2.5 NH 3 24.4 Mt in total 26.1 Mt in total 18.3 Mt in total11.8 Mt in total Zhao B. et al, AE, 2013

7. Validation of Radiation Data OBSNo feedbackRRTMGCAM Mean (MJ/m 2 )8.4811.2010.389.78 Mean_EAST (MJ/m 2 )5.206.025.895.78 R0.790.8250.805 NMB 0.320.220.15 NMB_EAST 0.160.130.11 China Radiation Day Value data sets EAST With feedback mechanism, the overestimation of radiation simulation is reduced.

8. NF Validation of Radiation Data CAM RRTMG By using feedback mechanism the simulation of radiation significantly improved during the heavily polluting period. NMB=0.40 NMB=0.23NMB=0.08 Beijing

9. Validation of Meteorological Condition with NCDC Data BIAS NFRRTMGCAM Temperature (K) -0.17-0.05-0.57 Wind speed （ m/s ） 0.13 0.09 Humidity (g/kg) 0.07 0.13

10. The Pollutant Distribution Comparison NF RRTMG CAM For the concentration of PM 2.5 CAM > RRTMG > NF Heavily polluting areas showed a larger difference.

11. The Pollutant Distribution Comparison North China Plain Compared with the scenario NF, scenario CAM shows a decrease of solar radiation, which leading to a decrease of surface temperature and O 3. Contract to O 3, other gas pollutant increases, such as NO 2.

12. Impact of Particulate Matter on Meteorology on North China Plain The increase of PM due to the radiation reduction is a nonlinear process. NF max =103.4 RRTMG max =113.4 CAM max =168.7 NF mean =130.7 RRTMG mean =114.6 CAM mean =100.8

13. Radiation Effects of Particulate Matters Enhanced the Temperature Inversion Dec. 17 Dec. 18

14. Process Analysis Except the meteorological parameter changing, the generation and growth of particle matters also plays an important role.

15. Particle Matter Species

16. The Factors Effects on Aerosol Chemistry The precursors of particle matter concentration increased due to the change of PBL.

17. The Factors Effects on Aerosol Chemistry The precursors of particle matter concentration increased due to the change of PBL. The change of radiation and atmospheric oxidation impacted on the chemical reaction balance, especially photochemical reaction.

18. The Factors Effects on Aerosol Chemistry The precursors of particle matter concentration increased due to the change of PBL. The change of radiation and atmospheric oxidation impacted on the chemical reaction balance, especially photochemical reaction. The change of temperature and RH impact on the chemical reaction balance.

19. Conclusion 1.By using feedback mechanism the simulation of radiation significantly improved during the heavily polluting period. 2.The increase of PM due to the radiation reduction is a nonlinear process. The heavily pollutant period and area showed a larger difference. The max difference can be 65% in North China Plain. 3.The difference is due to change of PBL height and aerosol process. They each accounted for about 50% in the first layer. 4.To quantify the contribution of each factors, more analysis is still needed in the future research.