Comparing Models of NOx Chemistry in Asia Tracey Holloway, Columbia University MICS-Asia Workshop 2001 Acknowledgements вЂўHiram Levy II, NOAA GFDL вЂўGreg Carmichael, University of Iowa вЂўMarkus Amann and TAP Project, IIASA вЂўMeredith Galanter, Larry Horowitz, Mahesh Phadnis вЂўSupport from DoD, NASA, Princeton Univ., GFDL Outline вЂў Model Overview вЂў Comparing with Observations вЂў Regional Lagrangian vs. Global Eulerian вЂў ATMOS-N Results ATMOS: Model Overview вЂў вЂў вЂў вЂў Lagrangian, forward 1o x 1o resolution NCEP winds (1990) NCEP precipitation вЂў Vertical motion by вЂњpuff splittingвЂќ вЂў Linear chemistry only, non-interacting puffs ATMOS-N Model Chemistry Fossil Fuel, Biomass Burning, Biogenic Fossil Fuel Emissions in Asia kTon NO2/grid-yr (IIASA, Van Ardenne) Model vs. Observations, I Annual Wet HNO3 Deposition (mg N/m2-yr) Observations from Dentener and Crutzen, 1994 Model vs. Observations, II Annual Wet HNO3 Deposition (mg N/m2-yr) Observations from Fujita et al., 2000 Model vs. Aircraft Obs OBS GFDL GCTM Feb.-Mar. ATMOS Sept.-Oct. Tropical W. Pac. Mid-lat. W. Pac. GCTM: Model Overview вЂў Global, Eulerian вЂў 11 vertical layers, variable resolution ~2.5o x 2.5o at midlatitutes вЂў GCM-generated winds/precipitation, вЂњtypicalвЂќ year вЂў Off-line chemistryвЂ”same scheme as ATMOS Deposition Budgets in 2 Models (kTon N/yr) GCTM, Asia FF % Emission ATMOS, Asia % Emission FF Fossil Fuel Emissions 6209 Wet HNO3 Dep 3209 52% 1775 36% Dry HNO3 Dep 1220 20% 1298 26% Dry NOx Dep 459 7% 278 6% Dry PAN Dep 146 2% 112 2% Total NOy Dep 5034 81% 3463 70% 4964 GCTM vs. ATMOS-N Global, Eulerian Regional, Lagrangian Annual Wet HNO3 Deposition (meq/m2-yr) ATMOS-N vs. GCTM, at sites ATMOS OBS GFDL GCTM Both models too low in wet HNO3 deposition, but ATMOS lower. ATMOS-N vs. GCTM, [HNO3] Surface Free Trop. (~685 mb) Summary: Model Evaluation вЂў Overall correct вЂњballparkвЂќ butвЂ¦ вЂў Wet HNO3 deposition too low vs. obs вЂў Disagreement greatest at вЂњdownwindвЂќ sites вЂў Upper Trop. NOx too low in summer вЂў Although GCTM is also too low in wet HNO3 deposition, ATMOS-N is lower вЂў Not enough lateral spreading вЂў Too much dry deposition вЂ¦ All trace back to the vertical transport in ATMOS-NвЂ¦ China Impacts Winter Summer % wet HNO3 deposition due to fossil fuel emissions in China relative to all Asia fossil fuel emissions India Impacts Winter Summer Japan Impacts Winter Summer Transfer Matrix for HNO3 TOвЂ¦ FROMвЂ¦ TAIW JAPAN TAIW 80% 2% JAPAN 1% N KOR S KOR 65% 1% 4% 3% 34% 7% S KOR 12% 20% 63% 18% 46% 26% 18% INDIA 1% INDIA 2% N KOR CHINA CHINA 1% 90% 6% 95% Relative Nitrate Burden Total= Total S + Total NO3(meq/m2/yr) % NO3- Summary: Regional Transfer of HNO3 вЂў Significant Transfer within east Asia, and from India to west China вЂў China contributes 18% to total nitrate deposition (wet + dry) in Japan, 46% to North Korea, 26% to South Korea вЂў Most exchange in winter, when winds are stronger, precipitation less вЂў NOx much more localized due to shorter lifetime вЂў Nitrate contributes 30-50% of total acidification over much of Japan, but less than 20% over much of east China.