Difference between revisions of "TransportTracers simulation"

Revision as of 13:46, 20 September 2022

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1. Simulations overview
2. Mechanisms for full-chemistry simulations (e.g. Standard, Tropchem, etc.)
3. Aerosol-only simulation
4. CH4 simulation
5. CO2 simulation
6. Hg simulation
7. POPs simulation
8. Tagged CO simulation
9. Tagged O3 simulation
10. TransportTracers simulation

This page contains information about the Radon-Lead-Beryllium (and optional passive species) 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).

The standard Rn-Pb-Be simulation uses the following tracers:

1. Rn²²², which is emitted naturally from soils
2. Pb²¹⁰, which is the primary decay product of Rn²²²
3. Be⁷, which is produced by cosmic rays in the stratosphere and upper atmosphere
4. Be¹⁰, which is produced by cosmic rays in the stratosphere and upper atmosphere (introduced in GEOS-Chem 12.2.0)

This simulation is most frequently used to validate the convection, advection, and wet scavenging processes in GEOS-Chem.

Starting in GEOS-Chem 12.2.0, the Rn-Pb-Be simulation has been expanded to include several passive species in a new "Transport Tracer simulation." Please see this wiki post for more information.

Zhang et al 2021 source

In GEOS-Chem 13.4.0 and later versions, a new Radon source function based on Zhang et al., 2021 was implemented. This is now the default emission source.

Jacob et al 1997 source

This emissions source (based on Jacob et al., 1997) was replaced by the Zhang et al., 2021 source. It still may be used as a research optioln.

--Bob Yantosca (talk) 13:43, 20 September 2022 (UTC)

Sinks

The table below shows the sinks for Rn²²², Pb²¹⁰, and Be⁷. In the equations below, ΔT is the emission timestep in seconds.

--Bob Yantosca (talk) 13:46, 20 September 2022 (UTC)

Non-local PBL mixing

Capability to use the non-local PBL mixing scheme was added in GEOS-Chem v9-02. Code updates were provided by Jintai Lin.

Karen Yu evaluated the non-local PBL mixing scheme in the Rn-Pb-Be simulation using GEOS-5 and GEOS-FP met fields. Please see these plots comparing the simulation with and without the non-local PBL mixing scheme.

--Bob Yantosca (talk) 16:43, 8 January 2016 (UTC)

Vertical Grid

This update was included in v11-02e (approved 24 Mar 2018).

Starting in GEOS-Chem v11-02e the default vertical grid used in Rn-Pb-Be simulations is the native 72-level grid for GEOS-FP and MERRA-2.

Lizzie Lundgren wrote:

The RnPbBe uses 47 levels by default (NO_REDUCED=n) for GEOS-Chem Classic and this is what we benchmark. GCHP, however, only uses the full 72 level grid. I recall that using either option gives the same result. I therefore wonder if we could change the GEOS-Chem Classic default to be 72 levels, consistent with GCHP. I do not think this would be significantly more expensive computationally.

--Melissa Sulprizio (talk) 18:08, 16 March 2018 (UTC)

Validation

The information was computed from 1-year Rn-Pb-Be benchmark simulations.

1-year benchmark simulations

Benchmark overview

1-year Rn-Pb-Be benchmark simulations are completed at the request of the Transport Working Group or whenever an update is introduced into the code that will impact transport and/or wet deposition. Each of these benchmarks involve a 4-year spinup period, followed by the 1-year run used for evaluation.

Benchmark plots

Budget of Pb210

In this table we plot the budgets of Pb²¹⁰ obtained from 1-year benchmark simulations at 4° x 5° resolution done with various GEOS-Chem versions.

NOTES:

• Bolded text denotes change in meteorology product and/or meteorology year.
• The simulations that utilized GEOS-5 met fields were done for year 2005, with a 4-year spinup. (Computed by Hongyu Liu)
• The benchmark simulations for v9-02r were done for June 2012–May 2013, with a 2-month spinup. This was due to data availability of the GEOS-FP met fields at the time of the simulation. (Completed by Karen Yu)
• The simulations for GEOS-Chem v10-01 and later versions utilized GEOS-FP met fields for the year 2013, with a 4-year spinup. The results reported here are for simulations using the non-local PBL mixing (VDIFF) scheme. (Completed by the GEOS-Chem Support Team)
• The simulations for GEOS-Chem 12.2.0 and later versions utilized GEOS-FP met fields for the year 2016, with a 10-year spinup. The results reported here are for simulations using the non-local PBL mixing (VDIFF) scheme. (Completed by the GEOS-Chem Support Team)
• Hongyu Liu and Bo Zhang are investigating the low Pb tropospheric lifetime against deposition observed in v11-01b using GEOS-FP. A quick fix was tested in v11-01d, but subsequently removed because of the high impact on aerosols. For more information, see this discussion on the Wet deposition wiki page.

Budget of Be7

In this table we plot the budgets of Be⁷ obtained from 1-year benchmark simulations at 4° x 5° resolution done with various GEOS-Chem versions.

NOTES:

• Bolded text denotes change in meteorology product and/or meteorology year.
• The simulations that utilized GEOS-5 met fields were done for year 2005, with a 4-year spinup. (Computed by Hongyu Liu)
• The benchmark simulations for v9-02r were done for June 2012–May 2013, with a 2-month spinup. This was due to data availability of the GEOS-FP met fields at the time of the simulation. (Completed by Karen Yu)
• The simulations for GEOS-Chem v10-01 and later versions utilized GEOS-FP met fields for the year 2013, with a 4-year spinup. The results reported here are for simulations using the non-local PBL mixing (VDIFF) scheme. (Completed by the GEOS-Chem Support Team)
• The simulations for GEOS-Chem 12.2.0 and later versions utilized GEOS-FP met fields for the year 2016, with a 10-year spinup. The results reported here are for simulations using the non-local PBL mixing (VDIFF) scheme. (Completed by the GEOS-Chem Support Team)

Radon flux diagnostic

This update will be added in GEOS-Chem v11-03.

Daniel Jacob wrote:

I suggest adding to the Rn-Pb-Be benchmark simulation a Rn flux diagnostic for a box across the coastal eastern US made up of 2x2 gridboxes in the horizontal and extending up to 3 levels in the vertical. This would allow testing of the horizontal fluxes as well as the vertical fluxes from advection, convection, and PBL mixing. Benchmark success would be measured by mass balance in that box and comparison to previous version. The first order of business will be to test whether we get a good Rn mass balance to test that the flux diagnostics (ND24, ND25, ND26) works.

--Melissa Sulprizio (talk) 21:39, 23 November 2016 (UTC)

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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