Difference between revisions of "TransportTracers simulation"

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(New page: This page contains information about the Radon-Lead-Beryllium simulation in GEOS-Chem. == Overview == The Rn-Pb-Be simulation in GEOS-Chem was based on that of the old Harvard/GISS CTM m...)
 
 
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This page contains information about the Radon-Lead-Beryllium simulation in GEOS-Chem.
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__FORCETOC__
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'''''[[Tagged O3 simulation|Previous]] | [[Guide to GEOS-Chem simulations|Next]] | [[Guide to GEOS-Chem simulations]]'''''
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#[[GEOS-Chem chemistry mechanisms|Simulations using KPP-built mechanisms]]
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#[[Aerosol-only simulation]]
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#[[CH4 simulation]]
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#[[CO2 simulation]]
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#[[Mercury|Hg simulation]]
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#[[POPs simulation]]
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#[[Tagged CO simulation]]
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#[[Tagged O3 simulation]]
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#<span style="color:blue">'''TransportTracers simulation'''</span>
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This page contains information about the TransportTracers (formerly Rn-Pb-Be) simulation in GEOS-Chem.
  
 
== Overview ==
 
== Overview ==
  
The Rn-Pb-Be simulation in GEOS-Chem was based on that of the old Harvard/GISS CTM model. The current simulation follows ''Liu et al'' [2001].   
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The Rn-Pb-Be simulation in GEOS-Chem was based on that of the old Harvard/GISS CTM model. The current simulation follows [http://acmg.seas.harvard.edu/publications/2001/liu2001.pdf Liu et al (2001)].   
  
The standard Rn-Pb-Be simulation uses the following tracers:
+
In [[GEOS-Chem 12#12.2.0|GEOS-Chem 12.2.0]] the Rn-Pb-Be simulation was extended to include additional passive species for benchmarking purposes and for diagnosing transport in GEOS-Chem. At this time the simulation was renamed to the '''''TransportTracer simulation'''''.
  
#Rn<sup>222</sup>, which is emitted naturally from soils
+
In [[GEOS-Chem 14.2.0]] the TransportTracers simulation was further modified so that species names and definitions are now consistent with GMAO's tracer gridded component (aka TR_GridComp). This will facilitate comparison of transport within GEOS-Chem, GCHP, and GEOS.
#Pb<sup>210</sup>, which is the primary decay product of Rn<sup>222</sup>
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#Be<sup>7</sup>, which is produced by cosmic rays in the stratosphere
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This simulation is most frequently used to validate the convection and advection processes in GEOS-Chem. 
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=== List of species ===
  
== Sources ==
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The transport tracers are summarized below.
  
The source of #Rn<sup>222</sup> is determined as follows (cf. ''Jacob et al'' [1997]):
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{| border=1 cellspacing=0 cellpadding=5
 +
|-bgcolor="#CCCCCC"
 +
!width="100px"|Species name
 +
!width="200px"|Description
 +
!width="300px"|Source
 +
!width="300px"|Sink
 +
!width="300px"|Purpose
  
#Rn<sup>222</sup> emission poleward of 70 degrees = 0.0 [atoms/cm2/s]
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|-valign="top"
#For latitudes 70S-60S and 60N-70N (both land & ocean), Rn<sup>222</sup> emission = 0.005 [atoms/cm2/s]
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|Rn222
#For latitudes between 60S and 60N:
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|Radon-222 isotope
#*Rn<sup>222</sup> over land = 1 [atoms/cm2/s] over land
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|
#*Rn<sup>222</sup> over land = 0.005 [atoms/cm2/s] over oceans
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*Emitted naturally from soils based on [https://acp.copernicus.org/articles/21/1861/2021/ Zhang et al., 2021].
#Where the surface temperature is below 0&deg; C, reduce Rn<sup>222</sup> emissions by a factor of 3.
+
|
 +
*Half-life of 3.83 days (Liu at al., 2001).
 +
**Decays into Pb<sup>210</sup> according to the exponential law:
 +
::<tt>EXP( -&Delta;T * 2.097d-6  )</tt>
 +
|Used to evaluate convection over land and strat-trop exchange
  
The source of Be<sup>7</sup> is taken from ''Lal and Peters'' [1967].
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|-valign="top"
 +
|Pb210
 +
|Lead-210 isotope
 +
|
 +
*Radioactive decay from Rn<sup>222</sup> according to the exponential law:
 +
::<tt>EXP( -&Delta;T * 2.097d-6  )</tt>
 +
::Where &Delta;T is the emission timestep in seconds.
 +
|
 +
*Half-life of 22.3 years (Liu et al., 2001).
 +
**Decays according to the exponential law:
 +
::<tt>EXP( -&Delta;T * 9.725d-10 )</tt>
 +
*Wet deposition
 +
*Dry deposition
 +
|Used to evaluate wet scavenging and transport
  
== Sinks ==
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|-valign="top"
 +
|Pb210s
 +
|Lead-210 isotope stratospheric-source tracer
 +
|
 +
*Same as Pb210 (restricted to the stratosphere)
 +
|
 +
*Same as Pb210
 +
|Used to evaluate strat-trop exchange
  
Rn<sup>222</sup> decays into Pb<sup>210</sup> according to the exponential law: <tt>EXP( -&Delta;T * 2.097d-6 )</tt>
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|-valign="top"
 +
|Be7
 +
|Beryllium-7 isotope
 +
|
 +
*Produced by cosmic rays as described in [https://link.springer.com/chapter/10.1007/978-3-642-46079-1_7 Lal and B. Peters, 1967]
 +
*Plus the following modifications from Liu et al. (2001):
 +
#Replace data at (0 hPa altitude, 70&deg;S latitude) following Koch (1996):
 +
#*old value = <tt>3000 disintegrations/g air/s</tt>
 +
#*new value = <tt>1900 disintegrations/g air/s</tt>
 +
#The original Lal & Peters data ended at 70&deg;S
 +
#*Copy the data values at 70&deg;S to 80&deg;S and 90&deg;S at all levels
 +
|
 +
*Half-life of 53.3 days (Liu et al., 2001).
 +
**Decays according to the exponential law:
 +
::<tt>EXP( -&Delta;T * 1.506d-7 )</tt>
 +
*Wet deposition
 +
*Dry deposition
 +
|Used to evaluate wet scavenging and strat-trop exchange
  
Pb<sup>210</sup> decays according to the exponential law: <tt>EXP( -&Delta;T * 9.725d-10 )</tt>
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|-valign="top"
 +
|Be7s
 +
|Beryllium-7 isotope stratospheric source tracer
 +
|
 +
*Same as Be7 (restricted to the stratosphere)
 +
|
 +
*Same as Be7
 +
|Used to evaluate strat-trop exchange
  
Be<sup>7</sup> decays according to the exponential law: <tt>EXP( -&Delta;T * 1.506d-7  )</tt>
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|-valign="top"
 +
|Be10
 +
|Beryllium-10 isotope
 +
|
 +
*Be<sup>10</sup> has an identical source distribution as Be<sup>7</sup> following Koch and Rind (1998).
 +
|
 +
*Half-life of 5.84e8 days (Koch and Rind, 1998).
 +
**Decays according to the exponential law:
 +
::<tt>EXP( -&Delta;T * 1.506d-7  )</tt>
 +
*Wet deposition
 +
*Dry deposition
 +
|Used to evaluate wet scavenging and strat-trop exchange
  
where -&Delta;T is the emission timestep in seconds.
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|-valign="top"
 +
|Be10s
 +
|Beryllium-10 isotope stratospheric source tracer
 +
|
 +
*Same as Be10 (restricted to the stratosphere)
 +
|
 +
*Same as Be10
 +
|Used to evaluate strat-trop exchange
  
== Validation ==
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|-valign="top"
 +
|PassiveTracer
 +
|Passive tracer with initial concentration of 100 ppb
 +
|
 +
*None
 +
|
 +
*None
 +
|Used to evaluate mass conservation in transport
  
See ''Liu et al'' [2001].
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|-valign="top"
 +
|SF6
 +
|Sulfur hexafluoride
 +
|
 +
*Anthropogenic emissions from EDGAR v4.2
 +
|
 +
*None
 +
|Used to evaluate inter-hemispheric transport of anthropogenic emissions
  
== References ==
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|-valign="top"
 +
|CH3I
 +
|Methyl iodide
 +
|
 +
*Emissions over the oceans of 1 molec/cm2/s
 +
|
 +
*5-day e-folding lifetime
 +
|Used to evaluate marine convection
  
#Liu, H., D. Jacob, I. Bey, and R.M. Yantosca, ''Constraints from 210Pb and 7Be on wet deposition and transport in a global three-dimensional chemical tracer model driven by assimilated meteorological fields'', <u>J. Geophys. Res</u>, '''106''', D11, 12,109-12,128, 2001.
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|-valign="top"
#Jacob et al., ''Evaluation and intercomparison of global atmospheric transport models using Rn-222 and other short-lived tracers'', <u>J. Geophys. Res</u>, '''102''', 5953-5970, 1997.
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|CO_25
#Koch, D. <u>J. Geophys. Res</u>, '''101''', D13, 18651, 1996.
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|Anthropogenic CO 25-day tracer
#Lal, D., and B. Peters, ''Cosmic ray produced radioactivity on the Earth''. <u>Handbuch der Physik</u>, '''46/2''', 551-612, edited by K. Sitte, Springer-Verlag, New York, 1967.
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|
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*Emissions from CEDS v2
 +
|
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*25-day e-folding lifetime
 +
|
 +
 
 +
|-valign="top"
 +
|CO_50
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|Anthropogenic CO 50-day tracer
 +
|
 +
*Emissions from CEDS v2
 +
|
 +
*50-day e-folding lifetime
 +
|
 +
 
 +
|-valign="top"
 +
|e90
 +
|Constant burden 90-day tracer
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|
 +
*Emitted globally at the surface such that the mixing ratio is maintained at 100 ppbv
 +
|
 +
*90-day e-folding lifetime
 +
|
 +
 
 +
|-valign="top"
 +
|e90_n
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|Constant burden Northern Hemisphere 90-day tracer
 +
|
 +
*Emitted at the surface such that the mixing ratio is maintained at 100 ppbv. Emissions source is restricted to 40N - 90N.
 +
|
 +
*90-day e-folding lifetime
 +
|
 +
 
 +
|-valign="top"
 +
|e90_s
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|Constant burden Southern Hemisphere 90-day tracer
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|
 +
*Emitted at the surface such that the mixing ratio is maintained at 100 ppbv. Emissions source is restricted to 90S - 40S.
 +
|
 +
*90-day e-folding lifetime
 +
|
 +
 
 +
|-valign="top"
 +
|aoa
 +
|Age of air uniform source tracer
 +
|
 +
*Increases by a value of 1 each emissions timestep
 +
|
 +
*Sink at the surface
 +
|Used for evaluating residual circulation and mixing
 +
 
 +
|-valign="top"
 +
|aoa_bl
 +
|Age of air uniform source tracer with sink restricted to the boundary layer
 +
|
 +
*Increases by a value of 1 each emissions timestep
 +
|
 +
*Sink in the boundary layer
 +
|Used for evaluating residual circulation and mixing
 +
 
 +
|-valign="top"
 +
|aoa_nh
 +
|Age of air uniform source tracer with sink restricted to a zone in the Northern Hemisphere
 +
|
 +
*Increases by a value of 1 each emissions timestep
 +
|
 +
*Sink at 30N - 50N
 +
|Used for evaluating residual circulation and mixing
 +
 
 +
|-valign="top"
 +
|nh_5
 +
|Northern Hemisphere 5-day tracer
 +
|
 +
*Constant source of 100 ppbv at latitudes 30N - 50N
 +
|
 +
*5-day e-folding lifetime
 +
|
 +
 
 +
|-valign="top"
 +
|nh_50
 +
|Northern Hemisphere 50-day tracer
 +
|
 +
*Constant source of 100 ppbv at latitudes 30N - 50N
 +
|
 +
*50-day e-folding lifetime
 +
|
 +
 
 +
|-valign="top"
 +
|st80_25
 +
|Stratospheric source 25-day tracer
 +
|
 +
*Constant source of 200 ppbv above 80 hPa
 +
|
 +
*25-day e-folding lifetime
 +
|
 +
 
 +
|}
 +
 
 +
== References ==
  
== Known issues ==
+
#Liu, H., D. Jacob, I. Bey, and R.M. Yantosca, ''Constraints from <sup>210</sup>Pb and <sup>7</sup>Be on wet deposition and transport in a global three-dimensional chemical tracer model driven by assimilated meteorological fields'', <u>J. Geophys. Res</u>, '''106''', D11, 12109-12128, 2001.
 +
#Jacob et al., ''Evaluation and intercomparison of global atmospheric transport models using <sup>222</sup>Rn and other short-lived tracers'', <u>J. Geophys. Res</u>, '''102''', 5953-5970, 1997.
 +
#Koch, D.M., D.J. Jacob, and W.C. Graustein, ''Vertical transport of tropospheric aerosols as indicated by <sup>7</sup>Be and <sup>210</sup>Pb in a chemical tracer model'', <u>J. Geophys. Res</u>, '''101''', D13, 18651-18666, 1996.
 +
#Koch, D., and D. Rind, ''Beryllium 10/beryllium 7 as a tracer of stratospheric transport'', <u>J. Geophys. Res.</u>, '''103''', D4, 3907-3917, 1998.
 +
#Lal, D., and B. Peters, ''Cosmic ray produced radioactivity on the Earth''. <u>Handbuch der Physik</u>, '''46/2''', 551-612, edited by K. Sitte, Springer-Verlag, New York, 1967.
  
None at this time
 
  
--[[User:Bmy|Bob Y.]] 10:07, 2 March 2011 (EST)
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----
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'''''[[Tagged O3 simulation|Previous]] | [[Guide to GEOS-Chem simulations|Next]] | [[Guide to GEOS-Chem simulations]]'''''

Latest revision as of 17:18, 24 October 2023

Previous | Next | Guide to GEOS-Chem simulations

  1. Simulations using KPP-built mechanisms
  2. Aerosol-only simulation
  3. CH4 simulation
  4. CO2 simulation
  5. Hg simulation
  6. POPs simulation
  7. Tagged CO simulation
  8. Tagged O3 simulation
  9. TransportTracers simulation


This page contains information about the TransportTracers (formerly Rn-Pb-Be) simulation in GEOS-Chem.

Overview

The Rn-Pb-Be simulation in GEOS-Chem was based on that of the old Harvard/GISS CTM model. The current simulation follows Liu et al (2001).

In GEOS-Chem 12.2.0 the Rn-Pb-Be simulation was extended to include additional passive species for benchmarking purposes and for diagnosing transport in GEOS-Chem. At this time the simulation was renamed to the TransportTracer simulation.

In GEOS-Chem 14.2.0 the TransportTracers simulation was further modified so that species names and definitions are now consistent with GMAO's tracer gridded component (aka TR_GridComp). This will facilitate comparison of transport within GEOS-Chem, GCHP, and GEOS.

List of species

The transport tracers are summarized below.

Species name Description Source Sink Purpose
Rn222 Radon-222 isotope
  • Half-life of 3.83 days (Liu at al., 2001).
    • Decays into Pb210 according to the exponential law:
EXP( -ΔT * 2.097d-6 )
Used to evaluate convection over land and strat-trop exchange
Pb210 Lead-210 isotope
  • Radioactive decay from Rn222 according to the exponential law:
EXP( -ΔT * 2.097d-6 )
Where ΔT is the emission timestep in seconds.
  • Half-life of 22.3 years (Liu et al., 2001).
    • Decays according to the exponential law:
EXP( -ΔT * 9.725d-10 )
  • Wet deposition
  • Dry deposition
Used to evaluate wet scavenging and transport
Pb210s Lead-210 isotope stratospheric-source tracer
  • Same as Pb210 (restricted to the stratosphere)
  • Same as Pb210
Used to evaluate strat-trop exchange
Be7 Beryllium-7 isotope
  • Produced by cosmic rays as described in Lal and B. Peters, 1967
  • Plus the following modifications from Liu et al. (2001):
  1. Replace data at (0 hPa altitude, 70°S latitude) following Koch (1996):
    • old value = 3000 disintegrations/g air/s
    • new value = 1900 disintegrations/g air/s
  2. The original Lal & Peters data ended at 70°S
    • Copy the data values at 70°S to 80°S and 90°S at all levels
  • Half-life of 53.3 days (Liu et al., 2001).
    • Decays according to the exponential law:
EXP( -ΔT * 1.506d-7 )
  • Wet deposition
  • Dry deposition
Used to evaluate wet scavenging and strat-trop exchange
Be7s Beryllium-7 isotope stratospheric source tracer
  • Same as Be7 (restricted to the stratosphere)
  • Same as Be7
Used to evaluate strat-trop exchange
Be10 Beryllium-10 isotope
  • Be10 has an identical source distribution as Be7 following Koch and Rind (1998).
  • Half-life of 5.84e8 days (Koch and Rind, 1998).
    • Decays according to the exponential law:
EXP( -ΔT * 1.506d-7 )
  • Wet deposition
  • Dry deposition
Used to evaluate wet scavenging and strat-trop exchange
Be10s Beryllium-10 isotope stratospheric source tracer
  • Same as Be10 (restricted to the stratosphere)
  • Same as Be10
Used to evaluate strat-trop exchange
PassiveTracer Passive tracer with initial concentration of 100 ppb
  • None
  • None
Used to evaluate mass conservation in transport
SF6 Sulfur hexafluoride
  • Anthropogenic emissions from EDGAR v4.2
  • None
Used to evaluate inter-hemispheric transport of anthropogenic emissions
CH3I Methyl iodide
  • Emissions over the oceans of 1 molec/cm2/s
  • 5-day e-folding lifetime
Used to evaluate marine convection
CO_25 Anthropogenic CO 25-day tracer
  • Emissions from CEDS v2
  • 25-day e-folding lifetime
CO_50 Anthropogenic CO 50-day tracer
  • Emissions from CEDS v2
  • 50-day e-folding lifetime
e90 Constant burden 90-day tracer
  • Emitted globally at the surface such that the mixing ratio is maintained at 100 ppbv
  • 90-day e-folding lifetime
e90_n Constant burden Northern Hemisphere 90-day tracer
  • Emitted at the surface such that the mixing ratio is maintained at 100 ppbv. Emissions source is restricted to 40N - 90N.
  • 90-day e-folding lifetime
e90_s Constant burden Southern Hemisphere 90-day tracer
  • Emitted at the surface such that the mixing ratio is maintained at 100 ppbv. Emissions source is restricted to 90S - 40S.
  • 90-day e-folding lifetime
aoa Age of air uniform source tracer
  • Increases by a value of 1 each emissions timestep
  • Sink at the surface
Used for evaluating residual circulation and mixing
aoa_bl Age of air uniform source tracer with sink restricted to the boundary layer
  • Increases by a value of 1 each emissions timestep
  • Sink in the boundary layer
Used for evaluating residual circulation and mixing
aoa_nh Age of air uniform source tracer with sink restricted to a zone in the Northern Hemisphere
  • Increases by a value of 1 each emissions timestep
  • Sink at 30N - 50N
Used for evaluating residual circulation and mixing
nh_5 Northern Hemisphere 5-day tracer
  • Constant source of 100 ppbv at latitudes 30N - 50N
  • 5-day e-folding lifetime
nh_50 Northern Hemisphere 50-day tracer
  • Constant source of 100 ppbv at latitudes 30N - 50N
  • 50-day e-folding lifetime
st80_25 Stratospheric source 25-day tracer
  • Constant source of 200 ppbv above 80 hPa
  • 25-day e-folding lifetime

References

  1. Liu, H., D. Jacob, I. Bey, and R.M. Yantosca, Constraints from 210Pb and 7Be on wet deposition and transport in a global three-dimensional chemical tracer model driven by assimilated meteorological fields, J. Geophys. Res, 106, D11, 12109-12128, 2001.
  2. Jacob et al., Evaluation and intercomparison of global atmospheric transport models using 222Rn and other short-lived tracers, J. Geophys. Res, 102, 5953-5970, 1997.
  3. Koch, D.M., D.J. Jacob, and W.C. Graustein, Vertical transport of tropospheric aerosols as indicated by 7Be and 210Pb in a chemical tracer model, J. Geophys. Res, 101, D13, 18651-18666, 1996.
  4. Koch, D., and D. Rind, Beryllium 10/beryllium 7 as a tracer of stratospheric transport, J. Geophys. Res., 103, D4, 3907-3917, 1998.
  5. Lal, D., and B. Peters, Cosmic ray produced radioactivity on the Earth. Handbuch der Physik, 46/2, 551-612, edited by K. Sitte, Springer-Verlag, New York, 1967.



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