Transport Working Group

All users interested in the GEOS-Chem transport scheme are encouraged to subscribe to the transport email list (click on the link in the contact information section section below).

Contact information

Transport Working Group Co-Chairs	Andrea Molod and Hongyu Liu
Transport Working Group email list	geos-chem-transport [at] g.harvard.edu
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--Bob Y. (talk) 18:38, 21 August 2015 (UTC)

Current GEOS-Chem Transport Projects (please add yours!)

User Group	Description	Contact Person
U. Toronto	Assessing impact of transport biases on methane simulation and applying weak constraint 4D-Var to correct them	Ilya Stanevich
U. Toronto	Characterizing model transport errors using weak constraint 4D-Var	Martin Keller
U. Toronto	Quantifying the impact of errors in PBL mixing on CO2	Wei Lu
Harvard	Examining the effect of grid resolution on vertical transport and convective mass fluxes	Karen Yu
Harvard	Quantifying the impact of numerical diffusion on plume transport and comparing to observed atmospheric diffusion	Sebastian D. Eastham
Harvard	Assessing the co-benefits of increasing vertical and horizontal grid resolutions for tracer transport	Jiawei Zhuang
Dalhousie	Implementation of a new PBL mixing scheme	Aaron van Donkelaar
NIA / NASA Langley	Constraints on Precipitation Scavenging and Transport of Soluble Trace Species From Airborne and Surface Radionuclide (222Rn, 210Pb, 7Be, 10Be) Observations	Bo Zhang Hongyu Liu
Harvard	Vertical resolution needs for GEOS-Chem global transport	Ada Shaw
Harvard U. Toronto	Re-diagnosed convection in off-line GEOS-Chem	Bob Yantosca Tailong He
Add yours here!

Current GEOS-Chem Transport Issues

Text to be added

Common set of transport tracers in GEOS-Chem and GEOS

This update will be included in GEOS-Chem 12.2.0.

The Transport Working Group proposed implementing additional tracers in GEOS-Chem for benchmarking purposes and for diagnosing transport in GEOS-Chem compared to GEOS-5. The GMI tracer suite is implemented via the tracer gridded component "TR_GridComp" in GEOS. In GEOS-Chem, the tracer suite has been added as an extension of the Rn-Pb-Be simulation (simulation type "1") by default, but may be added to any GEOS-Chem simulations by following the instructions below.

The current and future proposed transport tracers are summarized below.

Tracer name in GEOS-Chem	Tracer name in GEOS / GMI	Description	Version added
Rn222	Rn222	Radon-222 isotope See our Rn-Pb-Be wiki page for information on sources and sinks Used to evaluate convection over land and strat-trop exchange	GEOS-Chem v2-02
Pb210	Pb210	Lead-210 isotope See our Rn-Pb-Be wiki page for information on sources and sinks Used to evaluate convection over land and strat-trop exchange	GEOS-Chem v2-02
Pb210Strat	Pb210Strat	Lead-210 produces in the stratosphere See our Rn-Pb-Be wiki page for information on sources and sinks Used to evaluate convection over land and strat-trop exchange	GEOS-Chem 12.2.0
Be7	Be7	Beryllium-7 isotope See our Rn-Pb-Be wiki page for information on sources and sinks Used to evaluate strat-trop exchange	GEOS-Chem v2-02
Be7Strat	Be7Strat	Berylium-7 produced in the stratosphere Used to evaluate strat-trop exchange	GEOS-Chem 12.2.0
Be10	Be10	Beryllium-10 isotope Used to evaluate strat-trop exchange	GEOS-Chem 12.2.0
Be10Strat	Be10Strat	Beryllium-10 produced in the stratosphere Used to evaluate strat-trop exchange	GEOS-Chem 12.2.0
PassiveTracer	N/A	Passive tracer with initial concentration of 100 ppb (no emissions or decay) Used to evaluate mass conservation in transport	GEOS-Chem 12.2.0
SF6tracer	SF6	Sulfur hexafluoride with anthropogenic emissions from EDGAR v4.2 Used to evaluate inter-hemispheric transport of anthropogenic emissions	GEOS-Chem 12.2.0
CH3Itracer	CH3I	Methyl iodide with emissions over the oceans of 1 molec/cm2/s and a 5-day lifetime Used to evaluate marine convection	GEOS-Chem 12.2.0
COAnthroEmis25dayTracer	CO_25	CO tracer with anthropogenic emissions from CEDS and a 25-day lifetime	GEOS-Chem 12.2.0
COAnthroEmis50dayTracer	CO_50	CO tracer with anthropogenic emissions from CEDS and a 50-day lifetime	GEOS-Chem 12.2.0
COUniformEmis25dayTracer	Uniform	CO tracer with uniform surface emissions of 2400 Tg/yr and a 25-day lifetime Used for evaluating tropospheric mixing	GEOS-Chem 12.2.0
MaintainMixRatioGlobEmis90dayTracer	e90	Tracer emitted globally at the surface such that the mixing ratio is 100 ppbv and has a 90-day lifetime	GEOS-Chem 12.2.0
MaintainMixRatioNHEmis90dayTracer	e90_n	Tracer emitted in the Northern Hemisphere at the surface such that the mixing ratio is 100 ppbv and has a 90-day lifetime	GEOS-Chem 12.2.0
MaintainMixRatioSHEmis90dayTracer	e90_s	Tracer emitted in the Southern Hemisphere at the surface such that the mixing ratio is 100 ppbv and has a 90-day lifetime	GEOS-Chem 12.2.0
Clock	Clock	Age of air [s] Used for evaluating residual circulation and mixing Not implemented in GEOS-Chem as a tracer, but as a field in State_Met	GEOS-Chem 12.2.0
TBD	nh_5	Northern Hemisphere 5 day tracer	TBD
TBD	nh_50	Northern Hemisphere 50 day tracer	TBD
TBD	sh_5	Southern Hemisphere 5 day tracer	TBD
TBD	sh_50	Southern Hemisphere 50 day tracer	TBD
TBD	ntr_5	Northern Hemisphere Subtropical 5 day tracer	TBD
TBD	ntr_50	Northern Hemisphere Subtropical 50 day tracer	TBD
TBD	str_5	Southern Hemisphere Subtropical 5 day tracer	TBD
TBD	str_50	Southern Hemisphere Subtropical 50 day tracer	TBD
TBD	tr_5	Tropical 5 day tracer	TBD
TBD	tr_50	Tropical 50 day tracer	TBD
TBD	st80_25	Stratospheric source 25 day tracer	TBD
TBD	oNpbl	Origin tracer for 45N-90N and surface to ~800 hPa	TBD
TBD	oSpbl	Origin tracer for 45S-90S and surface to ~800 hPa	TBD
TBD	oStrat	Origin tracer for the stratosphere	TBD

Implementation in GEOS-Chem

Several of the GEOS tracers listed above have been added as passive species in GEOS-Chem. The new tracers are listed in the advected species menu of input.geos as:

%%% ADVECTED SPECIES MENU %%%:
Type of simulation      : 1
Species Entries ------->: Name
Species name            : Rn222
Species name            : Pb210
Species name            : Pb210Strat
Species name            : Be7
Species name            : Be7Strat
Species name            : Be10
Species name            : Be10Strat
Species name            : PassiveTracer
Species name            : SF6tracer
Species name            : CH3Itracer
Species name            : COAnthroEmis25dayTracer
Species name            : COAnthroEmis50dayTracer
Species name            : COUniformEmis25dayTracer
Species name            : MaintainMixRatioGlobEmis90dayTracer
Species name            : MaintainMixRatioNHEmis90dayTracer
Species name            : MaintainMixRatioSHEmis90dayTracer

In the passive species menu of input.geos, each species is defined along with the molecular weight, lifetime, default background concentration, and long name.

%%% PASSIVE SPECIES MENU %%%:
Passive species name    : PassiveTracer                        1.0  -1       1.0e-7   Passive_tracer_for_mass_conservation_evaluation
Passive species name    : SF6Tracer                          146.0  -1       1.0e-20  Sulfur_hexafluoride
Passive species name    : CH3ITracer                         142.0   4.32e5  1.0e-20  Methyl_iodide
Passive species name    : COAnthroEmis25dayTracer             28.0   2.16e6  1.0e-20  Anthropogenic_CO_with_25day_lifetime
Passive species name    : COAnthroEmis50dayTracer             28.0   4.32e6  1.0e-20  Anthropogenic_CO_with_50day_lifetime
Passive species name    : COUniformEmis25dayTracer            28.0   2.16e6  1.0e-20  CO_with_uniform_emission_and_25day_lifetime
Passive species name    : MaintainMixRatioGlobEmis90dayTracer  1.0   7.776e6 1.0e-20  Globally_emitted_tracer_with_90day_lifetime
Passive species name    : MaintainMixRatioNHEmis90dayTracer    1.0   7.776e6 1.0e-20  Northern_hemisphere_emitted_tracer_with_90day_lifetime
Passive species name    : MaintainMixRatioSHEmis90dayTracer    1.0   7.776e6 1.0e-20  Southern_hemisphere_emitted_tracer_with_90day_lifetime

Species with an emissions flux also have a corresponding entry in the HEMCO_Config.rc file.

#==============================================================================
# SF6 emissions from EDGAR v4.2
#==============================================================================
0 EDGAR_SF6  $ROOT/SF6/v2019-01/EDGAR_v42_SF6_IPCC_2.generic.01x01.nc emi_sf6 1970-2008/1-12/1/0 C xy kg/m2/s SF6Tracer - 1 1

#==============================================================================
# CH3I emitted over the oceans at rate of 1 molec/cm2/s
#==============================================================================
0 SRC_2D_CH3I 1.0 - - - xy molec/cm2/s CH3ITracer 1000 1 1

#==============================================================================
# Anthropogenic CO 25-day and 50-day tracers
#==============================================================================
0 CEDS_CO25d_ENE   $ROOT/CEDS/v2018-08/$YYYY/CO-em-anthro_CMIP_CEDS_$YYYY.nc  CO_ene  1950-2014/1-12/1/0 C xy kg/m2/s COAnthroEmis25dayTracer  26 1/2/12 5
0 CEDS_CO50d_ENE   -                                                          -       -                  - -  -       COAnthroEmis50dayTracer  26 1/2/12 5
0 CEDS_CO25d_IND   $ROOT/CEDS/v2018-08/$YYYY/CO-em-anthro_CMIP_CEDS_$YYYY.nc  CO_ind  1950-2014/1-12/1/0 C xy kg/m2/s COAnthroEmis25dayTracer  26 1/2/12 5
0 CEDS_CO50d_IND   -                                                          -       -                  - -  -       COAnthroEmis50dayTracer  26 1/2/12 5
0 CEDS_CO25d_TRA   $ROOT/CEDS/v2018-08/$YYYY/CO-em-anthro_CMIP_CEDS_$YYYY.nc  CO_tra  1950-2014/1-12/1/0 C xy kg/m2/s COAnthroEmis25dayTracer  26 1/2/12 5
0 CEDS_CO50d_TRA   -                                                          -       -                  - -  -       COAnthroEmis50dayTracer  26 1/2/12 5
0 CEDS_CO25d_RCO   $ROOT/CEDS/v2018-08/$YYYY/CO-em-anthro_CMIP_CEDS_$YYYY.nc  CO_rco  1950-2014/1-12/1/0 C xy kg/m2/s COAnthroEmis25dayTracer  26 1/2/12 5
0 CEDS_CO50d_RCO   -                                                          -       -                  - -  -       COAnthroEmis50dayTracer  26 1/2/12 5
0 CEDS_CO25d_SLV   $ROOT/CEDS/v2018-08/$YYYY/CO-em-anthro_CMIP_CEDS_$YYYY.nc  CO_slv  1950-2014/1-12/1/0 C xy kg/m2/s COAnthroEmis25dayTracer  26 1/2/12 5
0 CEDS_CO50d_SLV   -                                                          -       -                  - -  -       COAnthroEmis50dayTracer  26 1/2/12 5
0 CEDS_CO25d_WST   $ROOT/CEDS/v2018-08/$YYYY/CO-em-anthro_CMIP_CEDS_$YYYY.nc  CO_wst  1950-2014/1-12/1/0 C xy kg/m2/s COAnthroEmis25dayTracer  26 1/2/12 5
0 CEDS_CO50d_WST   -                                                          -       -                  - -  -       COAnthroEmis50dayTracer  26 1/2/12 5

#==============================================================================
# CO tracer with uniform surface emission of 2400 Tg/yr
#==============================================================================
0 SRC_2D_COUniform25d 1.5e-7 - - - xy kg/m2/s COUniformEmis25dayTracer - 1 1

...

1000 OCEAN_MASK $METDIR/$CNYR/01/$MET.$CNYR0101.CN.$RES.$NC FROCEAN 2000/1/1/0 C xy 1 1 -180/-90/180/90
1001 NH_MASK    -180/0/180/90  - 2000/1/1/0 C xy 1 1 -180/0/180/90
1002 SH_MASK    -180/-90/180/0 - 2000/1/1/0 C xy 1 1 -180/-90/180/0

--Melissa Sulprizio (talk) 13:12, 4 January 2019 (UTC)

Origin tracers

Chris Holmes wrote:

Another tracer suggestion: I like and use the "origin" tracers defined by Clara Orbe et al. (2013). These tracers give the fraction of air that that originates in specified source regions.

In addition to diagnosing transport, I think the tracers will be useful as templates for users to modify for their own purposes (e.g. customizing source regions). For that reason, a comprehensive set of tracers would be useful, if they can be optional.

Reference

Orbe, C., M. Holzer, L. M. Polvani, and D. Waugh (2013), Air-mass origin as a diagnostic of tropospheric transport, J. Geophys. Res. Atmos., 118, 1459–1470, doi:10.1002/jgrd.50133.

--Melissa Sulprizio (talk) 18:42, 23 February 2018 (UTC)