geos-chem users’ meeting harvard university gabriele curci6/2/2003 stratospheric chemistry and...

Gabriele Curci 6/2/2003 GEOS-CHEM users’ meetingHarvard University

Stratospheric chemistry and Stratospheric chemistry and SMVGEAR II in GEOS-CHEM SMVGEAR II in GEOS-CHEM

modelmodel

Gabriele CurciGabriele Curci

University of L’AquilaUniversity of L’Aquila


ROAD MAPROAD 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 simulationFull Stratospheric chemistry simulation– SMVGEAR II chemistry ODE solverSMVGEAR II chemistry ODE solver– Tropospheric-Stratospheric chemistry simulationTropospheric-Stratospheric chemistry simulation

• First evaluation of new capabilitiesFirst evaluation of new capabilities

• Conclusions and development needsConclusions and development needs

• Possible applicationsPossible applications


STRATOSPHERIC CHEMISTRY STRATOSPHERIC CHEMISTRY IN CURRENT GEOS-CHEMIN CURRENT GEOS-CHEM

Chem prod in Chem prod in tropospheretroposphere

49004900 Chem loss in Chem loss in tropospheretroposphere

42004200

Transport from Transport from stratospherestratosphere

500500 DepositionDeposition 12001200

Global sources and sinks of ozone (Tg O3 y-1) in GEOS-CHEM model

NOx emissions (Tg N y-1) to the troposphere

FOSSIL FUEL23.1

AIRCRAFT0.5

BIOFUEL2.2

SOILS5.1

LIGHTNING5.8

STRATOSPHERE0.2

BIOMASSBURNING

5.2


STRATOSPHERIC CHEMISTRY STRATOSPHERIC CHEMISTRY IN CURRENT GEOS-CHEMIN CURRENT GEOS-CHEM

• In UPBDFLX_MOD stratospheric OIn UPBDFLX_MOD stratospheric O33 (Synoz) (Synoz) and NOand NOxx fluxes are specified fluxes are specified

• Reactions with OH and photolysis of tracers Reactions with OH and photolysis of tracers are performed in SCHEM after call to are performed in SCHEM after call to SMVGEARSMVGEAR

• Monthly mean stratospheric OH, J-values, Monthly mean stratospheric OH, J-values, Prod/Loss of CO and NOProd/Loss of CO and NOxx are taken from are taken from Dylan Jones’ 2-D modelDylan Jones’ 2-D model

It would be helpful a better simulation of It would be helpful a better simulation of stratospheric chemistry?stratospheric chemistry?


A STRATOSPHERIC CHEMISTRY A STRATOSPHERIC CHEMISTRY VERSION OF GEOS-CHEMVERSION OF GEOS-CHEM

• It shares with standard model:It shares with standard model:– Input met fieldsInput met fields– Transport moduleTransport module– SMVGEAR chemistry ODE solverSMVGEAR chemistry ODE solver

• Stratospheric chemistry mechanism derived from STRATAQ Stratospheric chemistry mechanism derived from STRATAQ model from U. of L’Aquila [Grassi et. al, 2002]model from U. of L’Aquila [Grassi et. al, 2002]– 40 species, 120 kinetic reactions, 30 photolysis, 6 40 species, 120 kinetic reactions, 30 photolysis, 6

heterogeneous reactionsheterogeneous reactions– Heterogeneous chemistry on sulfate aerosol and PSCsHeterogeneous chemistry on sulfate aerosol and PSCs– PSC sedimentation (denitrification)PSC sedimentation (denitrification)

• 17 transported tracers + 8 long-lived species w/ fixed 17 transported tracers + 8 long-lived species w/ fixed distribution (CHdistribution (CH44, N, N22O, CFCs, CHO, CFCs, CH33Cl, CHCl, CH33Br…)Br…)

• Computes J-values using “SLOW-J” algorithmComputes J-values using “SLOW-J” algorithm

MAIN FEATURES OF THE MODEL


A STRATOSPHERIC CHEMISTRY A STRATOSPHERIC CHEMISTRY VERSION OF GEOS-CHEM: VERSION OF GEOS-CHEM: EVALUATIONEVALUATION

Stratospheric GEOS-

CHEM ozone column

vs

TOMS column

(1998)


SMVGEAR II IN GEOS-CHEMSMVGEAR II IN GEOS-CHEM

• Sparse-Matrix-Vectorized Gear type chemical ODE Sparse-Matrix-Vectorized Gear type chemical ODE solver version 2solver version 2

• Main differences vs. SMVGEAR version 1:Main differences vs. SMVGEAR version 1:– Allows for different chemistry sets in different regions of the Allows for different chemistry sets in different regions of the

atmosphere (e.g., urban, free troposphere, stratosphere)atmosphere (e.g., urban, free troposphere, stratosphere)– Grid reordering according to stiffness for computational Grid reordering according to stiffness for computational

efficiencyefficiency

A GEOS-CHEM 1-month run using SMVGEAR II reveals:A GEOS-CHEM 1-month run using SMVGEAR II reveals:

• 20 min/day vs. 23 min/day on IBM/AIX platform20 min/day vs. 23 min/day on IBM/AIX platform

• 10 h/month vs. 11.5 h/month on IBM/AIX platform10 h/month vs. 11.5 h/month on IBM/AIX platform

• different concentrationsdifferent concentrations

MAIN FEATURES OF THE PACKAGE


SMVGEAR II IN GEOS-CHEM: SMVGEAR II IN GEOS-CHEM: EVALUATIONEVALUATION

Relative differences

between SMV1 and

SMV2 simulations

after 1 month

NOx

-1.6 ÷ 0.2 %




between SMV1 and

SMV2 simulations

after 1 month

Ox

0 ÷ 1.6 %




between SMV1 and

SMV2 simulations

after 1 month

CO-0.55 ÷ 0 %




between SMV1 and

SMV2 simulations

after 1 month

OH0 ÷ 10 %


TROPOSPHERIC-STRATOSPHERIC TROPOSPHERIC-STRATOSPHERIC CHEMISTRY SIMULATIONCHEMISTRY SIMULATION

IF ( LEVEL < TROPOPAUSE ) THENIF ( LEVEL < TROPOPAUSE ) THENSTANDARD TROPOSPHERIC CHEMISTRY

MECHANISM80 species, 288 kinetic reactions, 51 photolysis, 5

heterogeneous reactions

ELSEELSENEW STRATOSPHERIC CHEMISTRY

MECHANISM40 species, 120 kinetic reactions, 30 photolysis, 6

heterogeneous reactions

BASIC IDEA OF THE SIMULATION


TROPOSPHERIC-STRATOSPHERIC TROPOSPHERIC-STRATOSPHERIC CHEMISTRY SIMULATIONCHEMISTRY SIMULATION

• It is implemented on:It is implemented on:– Version 5.02 (fvDAS compatibility, pressure fixer)Version 5.02 (fvDAS compatibility, pressure fixer)– GEOS-3 met-fields with 48 GEOS-3 met-fields with 48 -levels-levels– NONOxx-O-Oxx-Hydrocarbons simulation (NSCRX=3)-Hydrocarbons simulation (NSCRX=3)

• Uses Uses SMVGEAR II chemistry solver chemistry solver• 6 new tracers for the stratosphere: 6 new tracers for the stratosphere: ClOx, BrOx, HCl, HBr,

ClONO2, BrONO2 (total of 30 tracers) (total of 30 tracers)• Revised ORevised Oxx = O = O33+NO+NO22+2NO+2NO33+O+O(1D) to make it suitable to make it suitable

for the stratospherefor the stratosphere• Photorates: Photorates: FAST-J in the troposphere and in the troposphere and SLOW-J in the in the

stratospherestratosphere

MAIN FEATURES OF THE MODEL


TROPOSPHERIC-STRATOSPHERIC TROPOSPHERIC-STRATOSPHERIC CHEMISTRY SIMULATION: CHEMISTRY SIMULATION: EVALUATIONEVALUATION


between STD and T-S simulations

Ox

0 ÷ 60 %


TROPOSPHERIC-STRATOSPHERIC TROPOSPHERIC-STRATOSPHERIC CHEMISTRY SIMULATION: CHEMISTRY SIMULATION: EVALUATIONEVALUATION

Zonal mean of Ox in January


CONCLUSIONS AND CONCLUSIONS AND DEVELOPMENT NEEDSDEVELOPMENT NEEDS

• New capabilities have been developed to improve New capabilities have been developed to improve stratospheric chemistry simulation into GEOS-CHEM stratospheric chemistry simulation into GEOS-CHEM model:model:– Full stratospheric chemistry modelFull stratospheric chemistry model– Tropospheric-stratospheric chemistry model to be Tropospheric-stratospheric chemistry model to be

improvedimproved

• The new simulations require deep changes to the The new simulations require deep changes to the codecode

• Changes imply adaptation of other parts of the Changes imply adaptation of other parts of the code (diagnostics, other simulation types…)code (diagnostics, other simulation types…)

• The new code is not yet implemented for parallel The new code is not yet implemented for parallel computingcomputing


POSSIBLE APPLICATIONSPOSSIBLE APPLICATIONS

• STE and stratospheric influence studiesSTE and stratospheric influence studies• Comparison of GEOS and fvDAS data Comparison of GEOS and fvDAS data

(cross-tropopause fluxes)(cross-tropopause fluxes)• Satellite data retrieval (better a-priori for Satellite data retrieval (better a-priori for

the stratosphere)the stratosphere)• Halogen chemistryHalogen chemistry• Chemistry-radiation feedback (compute J-Chemistry-radiation feedback (compute J-

values using calculated Ovalues using calculated O33))


ENDEND

THANKS FOR YOUR ATTENTION! THANKS FOR YOUR ATTENTION!

geos-chem users’ meeting harvard university gabriele curci6/2/2003 stratospheric chemistry and...

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