1. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 Stratospheric chemistry and SMVGEAR II in GEOS-CHEM model Gabriele Curci University of L’Aquila

2. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 ROAD MAP Role of the stratosphere in GEOS-CHEM modelRole of the stratosphere in GEOS-CHEM model New capabilities of GEOS-CHEM:New capabilities of GEOS-CHEM: –Full Stratospheric chemistry simulation –SMVGEAR II chemistry ODE solver –Tropospheric-Stratospheric chemistry simulation First evaluation of new capabilitiesFirst evaluation of new capabilities Conclusions and development needsConclusions and development needs Possible applicationsPossible applications

3. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 STRATOSPHERIC CHEMISTRY IN CURRENT GEOS-CHEM Chem prod in troposphere 4900 Chem loss in troposphere 4200 Transport from stratosphere 500Deposition1200 Global sources and sinks of ozone (Tg O 3 y -1 ) in GEOS-CHEM model NO x emissions (Tg N y -1 ) to the troposphere FOSSIL FUEL 23.1 AIRCRAFT 0.5 BIOFUEL 2.2 SOILS 5.1 LIGHTNING 5.8 STRATOSPHERE 0.2 BIOMASS BURNING 5.2

4. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 STRATOSPHERIC CHEMISTRY IN CURRENT GEOS-CHEM In UPBDFLX_MOD stratospheric O 3 (Synoz) and NO x fluxes are specifiedIn UPBDFLX_MOD stratospheric O 3 (Synoz) and NO x fluxes are specified Reactions with OH and photolysis of tracers are performed in SCHEM after call to SMVGEARReactions with OH and photolysis of tracers are performed in SCHEM after call to SMVGEAR Monthly mean stratospheric OH, J-values, Prod/Loss of CO and NO x are taken from Dylan Jones’ 2-D modelMonthly mean stratospheric OH, J-values, Prod/Loss of CO and NO x are taken from Dylan Jones’ 2-D model It would be helpful a better simulation of stratospheric chemistry?

5. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 A STRATOSPHERIC CHEMISTRY VERSION OF GEOS-CHEM It shares with standard model:It shares with standard model: –Input met fields –Transport module –SMVGEAR chemistry ODE solver Stratospheric chemistry mechanism derived from STRATAQ model from U. of L’Aquila [Grassi et. al, 2002]Stratospheric chemistry mechanism derived from STRATAQ model from U. of L’Aquila [Grassi et. al, 2002] –40 species, 120 kinetic reactions, 30 photolysis, 6 heterogeneous reactions –Heterogeneous chemistry on sulfate aerosol and PSCs –PSC sedimentation (denitrification) 17 transported tracers + 8 long-lived species w/ fixed distribution (CH 4, N 2 O, CFCs, CH 3 Cl, CH 3 Br…)17 transported tracers + 8 long-lived species w/ fixed distribution (CH 4, N 2 O, CFCs, CH 3 Cl, CH 3 Br…) Computes J-values using “SLOW-J” algorithmComputes J-values using “SLOW-J” algorithm MAIN FEATURES OF THE MODEL

6. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 A STRATOSPHERIC CHEMISTRY VERSION OF GEOS-CHEM: EVALUATION Stratospheric GEOS-CHEM ozone column vs TOMS column (1998)

7. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 A STRATOSPHERIC CHEMISTRY VERSION OF GEOS-CHEM: EVALUATION Simulation of the Antarctic Ozone Hole (1998)

8. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 SMVGEAR II IN GEOS-CHEM Sparse-Matrix-Vectorized Gear type chemical ODE solver version 2Sparse-Matrix-Vectorized Gear type chemical ODE solver version 2 Main differences vs. SMVGEAR version 1:Main differences vs. SMVGEAR version 1: –Allows for different chemistry sets in different regions of the atmosphere (e.g., urban, free troposphere, stratosphere) –Grid reordering according to stiffness for computational efficiency A GEOS-CHEM 1-month run using SMVGEAR II reveals: 20 min/day vs. 23 min/day on IBM/AIX platform 20 min/day vs. 23 min/day on IBM/AIX platform 10 h/month vs. 11.5 h/month on IBM/AIX platform 10 h/month vs. 11.5 h/month on IBM/AIX platform different concentrations different concentrations MAIN FEATURES OF THE PACKAGE

9. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 SMVGEAR II IN GEOS-CHEM: EVALUATION Relative differences between SMV1 and SMV2 simulations after 1 month NO x -1.6 ÷ 0.2 %

10. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 SMVGEAR II IN GEOS-CHEM: EVALUATION Relative differences between SMV1 and SMV2 simulations after 1 month O x 0 ÷ 1.6 %

11. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 SMVGEAR II IN GEOS-CHEM: EVALUATION Relative differences between SMV1 and SMV2 simulations after 1 month CO -0.55 ÷ 0 %

12. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 SMVGEAR II IN GEOS-CHEM: EVALUATION Relative differences between SMV1 and SMV2 simulations after 1 month OH 0 ÷ 10 %

13. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 TROPOSPHERIC-STRATOSPHERIC CHEMISTRY SIMULATION IF ( LEVEL < TROPOPAUSE ) THEN   STANDARD TROPOSPHERIC CHEMISTRY MECHANISM 80 species, 288 kinetic reactions, 51 photolysis, 5 heterogeneous reactionsELSE   NEW STRATOSPHERIC CHEMISTRY MECHANISM 40 species, 120 kinetic reactions, 30 photolysis, 6 heterogeneous reactions BASIC IDEA OF THE SIMULATION

14. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 TROPOSPHERIC-STRATOSPHERIC CHEMISTRY SIMULATION It is implemented on:It is implemented on: –Version 5.02 (fvDAS compatibility, pressure fixer) –GEOS-3 met-fields with 48  -levels –NO x -O x -Hydrocarbons simulation (NSCRX=3) Uses chemistry solverUses SMVGEAR II chemistry solver 6 new tracers for the stratosphere: (total of 30 tracers)6 new tracers for the stratosphere: ClO x, BrO x, HCl, HBr, ClONO 2, BrONO 2 (total of 30 tracers) Revised O x = O 3 +NO 2 +2NO 3 to make it suitable for the stratosphereRevised O x = O 3 +NO 2 +2NO 3 +O+O( 1 D) to make it suitable for the stratosphere Photorates: in the troposphere and in the stratospherePhotorates: FAST-J in the troposphere and SLOW-J in the stratosphere MAIN FEATURES OF THE MODEL

15. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 TROPOSPHERIC-STRATOSPHERIC CHEMISTRY SIMULATION Implementation of SMVGEAR II packageImplementation of SMVGEAR II package Added C-preprocessor switch STRATCHEM to activate specific capabilitiesAdded C-preprocessor switch STRATCHEM to activate specific capabilities Enhanced labeling of trop/strat boxesEnhanced labeling of trop/strat boxes Contemporaneous use of FAST-J and SLOW-JContemporaneous use of FAST-J and SLOW-J Implementation of stratospheric heterogeneous chemistry and PSCs sedimentationImplementation of stratospheric heterogeneous chemistry and PSCs sedimentation Revised O x partitioning before call to chemistry solverRevised O x partitioning before call to chemistry solver MAIN MODIFICATIONS TO THE CODE

16. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 TROPOSPHERIC-STRATOSPHERIC CHEMISTRY SIMULATION: EVALUATION Relative differences between STD and T-S simulations O x 0 ÷ 60 %

17. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 TROPOSPHERIC-STRATOSPHERIC CHEMISTRY SIMULATION: EVALUATION Zonal mean of O x in January

18. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 TROPOSPHERIC-STRATOSPHERIC CHEMISTRY SIMULATION: EVALUATION Zonal mean of O x in January

19. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 CONCLUSIONS AND DEVELOPMENT NEEDS New capabilities have been developed to improve stratospheric chemistry simulation into GEOS-CHEM model:New capabilities have been developed to improve stratospheric chemistry simulation into GEOS-CHEM model: –Full stratospheric chemistry model –Tropospheric-stratospheric chemistry model to be improved The new simulations require deep changes to the codeThe new simulations require deep changes to the code Changes imply adaptation of other parts of the code (diagnostics, other simulation types…)Changes imply adaptation of other parts of the code (diagnostics, other simulation types…) The new code is not yet implemented for parallel computingThe new code is not yet implemented for parallel computing

20. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 POSSIBLE APPLICATIONS STE and stratospheric influence studiesSTE and stratospheric influence studies Comparison of GEOS and fvDAS data (cross- tropopause fluxes)Comparison of GEOS and fvDAS data (cross- tropopause fluxes) Satellite data retrieval (better a-priori for the stratosphere)Satellite data retrieval (better a-priori for the stratosphere) Halogen chemistryHalogen chemistry Chemistry-radiation feedback (compute J-values using calculated O 3 )Chemistry-radiation feedback (compute J-values using calculated O 3 )

21. GEOS-CHEM users’ meeting Harvard University Gabriele Curci6/2/2003 END THANKS FOR YOUR ATTENTION! END THANKS FOR YOUR ATTENTION!