1. Chemistry-Climate Interaction Studies in Japan Hajime Akimoto Atmospheric Composition Research Program Frontier Research System for Global Change Chemistry Climate Interactions Workshop, Santa Fe, February 10-12, 2003

2. Only one AGCM-Based Chemical Transport Model “ CHASER ” = CCSR/NIES AGCM + Tropospheric Chemistry (gas Phase) Development of CHASER CCSR: Center for Climate System Research, UT RCAST: Research Center for Advanced Science and Technology, UT FRSGC: Frontier Research System for Global Change Model Description and validation Sudo, K., M. Takahashi, J. Kurokawa, and H. Akimoto, J. Geophys., Res., 107 (D17), 10.1029/2001JD001113, 2002. Sudo, K., M. Takahashi, and H. Akimoto, J. Geophys., Res., 107 (D17), 10.1029/2001JD001114, 2002. Present Status of Chemistry-Climate Research in Japan

3. Present Status of CHASER Horizontal resolution: T21 (5.6 ゜ ) / T42 (2.8 ゜ ) Vertical resolution: 32 layer (Upper boundary ca. 35 km) Advection Scheme: Flux-Form Semi-Lagransian [Lin and Rood, 1996] Radiation Scheme: Discrete Ordinate Method + k- distribution[Nakajima et al., 1996] Chemistry Scheme: Tropospheric chemistry up to ca. 20 km Chemical Species: 51 Gas phase reactions: 94 Photolytic reactions: 24 Liquid phase reactions: 4 Heterogeneous reactions: 1

4. Radiative forcing (W m -2 ) due to tropospheric ozone increase calculated by CHASER （ preindustrial  present-day ） 0.3820.5920.487 LW ＋ SW 0.0630.1070.085SW 0.3190.4850.402LW SHNHGlobal LW ＋ SW total ozone forcing DJF JJA Tropospheric ozone radiative forcing W m -2 (at tropopause, in annual mean) Normalized radiative forcing = 0.047 W m -2 DU -1 Tropospheric ozone increase 197 TgO 3 (preindustrial) ↓ +10.4 DU (+58%) 311 TgO 3 (present-day)

5. Radiative forcing (W m -2 ) due to tropospheric ozone increase （ preindustrial  present-day ） (W m -2 ) This work (0.49 W m -2 ) Global mean radiative forcing

6. SRES-A2 Emission Scenario Future prediction experiment of tropospheric ozone

7. Change of Tropospheric Ozone Production Rate SRES-A2 1990  2050  2100

8. The meteorological effect of El Nino (1997) on the tropospheric chemistry Difference (anomaly) : October 1997 minus October 1996 [Sudo and Takahashi, 2001]

9. Changes over 10 o S-10 o N (Lon.-Alt.) Ozone (ppbv)  Convective mass flux  & up/downward motions Specific humidity (g/kg)  Ozone chemical lifetime (%)  Oct. 1997 minus Oct. 1996

10. Future Plan using CHASER Model Development Inclusion of aerosol model Integration of stratospheric chemistry model Model Simulation Past simulation and Future prediction of air quality based on new emission models Global warming Prediction using fully-coupled CHASER/AGCM

11. Concept of Integrated Model Development at FRSGC Climate (CCSR/NIES AGCM 5.7) Chemistry (CHASER) Aerosol (SPRINTARS) Land Surface (MATSIRO,Sym-CYCLE) Ocean (an NPZD-type model) transport radiation cloud distribution transport radiation production heterogeneous reaction DMS NMHCsCO 2 Sea Saltdust, OC SST mineral