1. GEOS-CHEM Activities at NIA Hongyu Liu National Institute of Aerospace (NIA) at NASA LaRC June 2, 2003

2. 210 Pb- 7 Be-O 3 relationships

3. 210 Pb- 7 Be-O 3 relationships during PEM-West A (Sept-Oct 1991) Near AsiaRemote Pacific Near Asia 210 Pb-O 3 7 Be-O 3 UT MT LT OBSERVATION vs. MODEL

4. 210 Pb- 7 Be-O 3 relationships during PEM-West B 210 Pb-O 3 7 Be-O 3 UT LT MT OBSERVATION vs. MODEL Near AsiaRemote PacificNear AsiaRemote Pacific

5. 210 Pb- 7 Be-O 3 relationships during TRACE-P < 30 o N> 30 o N< 30 o N> 30 o N 210 Pb-O 3 7 Be-O 3 UT LT MT OBSERVATION vs. MODEL

6. RAQMS (regional) & GEOS-CHEM (global); LaRC/UW Regional Air Quality Modeling System (RAQMS) jointly developed by NASA Langley and Univ Wisconsin [Pierce et al., 2003]; Fast-J2 scheme recently implemented in RAQMS Cloud and trace gas distributions Cloud optical depth (model vs. satellite) …… The effect of clouds on Asian pollution outflow during TRACE-P (with Brad Pierce, Jim Crawford, et al.)

7. Intercontinental transport, Continental outflow, and Chemical processing of aerosols with GEOS-CHEM Duncan Fairlie* Rokjin Park Daniel Jacob Dept. Earth and Planetary Sciences Harvard University *Also NASA Langley Research Center, Hampton, VA 2 June 2003

8. Project Goals: (1)Assess the impact of intercontinental transport of mineral dust on aerosol concentrations in North America (2) Assess the global impact of heterogeneous uptake on mineral dust on SO 4 = production and NO y partitioning (3) Quantify export of aerosols and precursors from the North America, and relate to sources.

9. Aerosol Module in GEOS-CHEM Aerosol Module: Based on GOCART (Chin et al., 2002): SO 4, sea salt, dust, OC, EC. Added NH 3 (Adams et al., 1999), H 2 SO 4 -HNO 3 -NH 3 -H 2 O thermodynamics (Nenes et al., 1998). Rokjin Park Dust module: Mobilization: Ginoux et al. (2001) Dry deposition: Zhang et al. (2000) Wet deposition: Liu et al. (2001) Dust size bins: 0.1-1.0, 1.0-1.8, 1.8-3.0, 3.0-6.0  m radius. Full coupling with oxidant-aerosol chemistry: gas-aqueous sulfur oxidation; HNO 3 /nitrate partitioning; heterogeneous uptake of N 2 O 5, NO 2, NO 3, HO 2 ; impact on photolysis rates.

10. 1. How much does Asian dust contribute to concentrations over North America? Use GEOS-CHEM to quantify intercontinental transport of dust to the U.S. Evaluate the model with data from the IMPROVE network, AERONET observations, TRACE-P and ACE-Asia data, and MODIS AOD. Assess the model against the constraints of observations. Simulated dust April, 2001

11. 2001 annual dust simulation Total Emission: 2500Tg/yrDRYD: 1400Tg/yr WETD: 1100Tg/yr Avg. Burden: 37Tg 200 500 50 2000 mg/m 2 Tons/km 2 /yr

12. IMPROVE sites: extreme Asian dust event in April 2001 0 4 8  g/m 3 16 April, 200122 April 2001 IMPROVE Dust PM2.5

13. IMPROVE PM2.5 dust MODEL w/ all sources Model w/o NA sources 18 west sites 12 east sites Discrepancies between model and data suggest local sources too strong April 2001

14. 2. Evaluate global impact of uptake of SO 4 = and NO 3 - on dust GEOS-CHEM - fully coupled aerosol-gas simulation. Uptake of HNO 3, SO 2, H 2 SO 4 on dust. Carry alkalinity as a tracer to limit uptake Distinguish alkalinity differences at source. Use obs. to assess simulation, and constrain sources. TRACE-P ACE-Asia

15. 3. Impact of continental outflow on the global atmosphere : Key science objective of INTEX:  What is the aerosol outflow from N. America, and how does it relate to surface sources?  What are the outflow mechanisms, and how do they differ for aerosols, gases? INTEX Mission 2004

16. The role of dust: Navajo Mountain, Page, AZ typical view 16 April 2001 EPA regional haze rule: “return Federal Class I regions to natural visibility conditions by 2064.” Dust arrives behind cold front SeaWifs 11 April

17. Chemical modification due to uptake of HNO 3, SO 2, H 2 SO 4 on mineral dust Change global NO x /HNO 3 partitioning. and impact O 3 budget. Speed up SO 2 conversion to sulfate, and impact the SO 4 = lifetime. Make dust hygroscopic and promote additional aqueous surface reactions, e.g. SO 2, N 2 O 5 Shift aerosol sizes to larger particles. Impact radiative properties.