TransportTracers simulation

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  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.

Species Chemical source
Rn222 The default source of Rn222 follows Jacob et al. (1997):
Latitudes Rn222 Emission
90°N - 70°N
  • Everywhere: 0.0 atoms/cm2/s
70°N - 60°N
  • Everywhere: 0.005 atoms/cm2/s
  • Reduce emissions by a factor of 3 where surface temperature < 0° C
60°N - 60°S
  • Over land: 1 atom/cm2/s
  • Over oceans: 0.005 atoms/cm2/s
  • Reduce emissions by a factor of 3 where surface temperature < 0° C
60°S - 70°S
  • Everywhere: 0.005 atoms/cm2/s
  • Reduce emissions by a factor of 3 where surface temperature < 0° C
70°S - 90°S
  • Everywhere: 0.0 atoms/cm2/s


In GEOS-Chem 13.4.0 and later versions, users will have the option of replacing the default Rn222 emissions (described above) with emissions from Bo Zhang et al [2021] (DOI: 10.5194/acp-21-1861-2021).

Pb210 Radioactive decay from Rn222 according to the exponential law:
  • EXP( -ΔT * 2.097d-6 )

Where ΔT is the emission timestep in seconds.

Be7
Be7Strat 		The source of Be7 is taken from the following reference:
  • 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.

with 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
Be10
Be10 		Be10 has an identical source distribution as Be7 following Koch and Rind (1998).

--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.

Species Chemical sink Drydep sink? Wetdep sink?
Rn222 Half-life of 3.83 days (Liu at al., 2001).

Decays into Pb210 according to the exponential law:

  • EXP( -ΔT * 2.097d-6 )
 no no
Pb210 Half-life of 22.3 years (Liu et al., 2001).

Decays according to the exponential law:

  • EXP( -ΔT * 9.725d-10 )
 yes yes
Be7
Be7Strat 		Half-life of 53.3 days (Liu et al., 2001).

Decays according to the exponential law:

  • EXP( -ΔT * 1.506d-7 )
 yes yes
Be10
Be10Strat 		Half-life of 5.84e8 days (Koch and Rind, 1998).

Decays according to the exponential law:

  • EXP( -ΔT * 1.506d-7 )
 yes yes

--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

Version Link
12.8.0
w/ GEOS-FP 		http://ftp.as.harvard.edu/gcgrid/geos-chem/1yr_benchmarks/GC_12/12.8.0/
12.2.0
w/ GEOS-FP 		http://ftp.as.harvard.edu/gcgrid/geos-chem/1yr_benchmarks/GC_12/12.2.0/TransportTracers/output/
v11-02e
w/ GEOS-FP (2016 met) 		http://ftp.as.harvard.edu/gcgrid/geos-chem/1yr_benchmarks/v11-02/v11-02e/RnPbBePasv-Run2/NLPBL/output/
v11-02e
w/ GEOS-FP (72 levels) 		http://ftp.as.harvard.edu/gcgrid/geos-chem/1yr_benchmarks/v11-02/v11-02e/RnPbBePasv-Run1/NLPBL/output/
v11-02e
w/ GEOS-FP (2013 met) 		http://ftp.as.harvard.edu/gcgrid/geos-chem/1yr_benchmarks/v11-02/v11-02e/RnPbBePasv-Run0/NLPBL/output/
v11-02b
w/ GEOS-FP 		http://ftp.as.harvard.edu/gcgrid/geos-chem/1yr_benchmarks/v11-02/v11-02b/RnPbBePasv/RnPbBePasv_VDIFF/output/
v11-01i
w/ GEOS-FP 		http://ftp.as.harvard.edu/gcgrid/geos-chem/1yr_benchmarks/v11-01/v11-01i/RnPbBePasv/RnPbBePasv_VDIFF/output/
v11-01h
w/ GEOS-FP 		http://ftp.as.harvard.edu/gcgrid/geos-chem/1yr_benchmarks/v11-01/v11-01h/RnPbBePasv/RnPbBePasv_VDIFF/output/
v11-01f
w/ MERRA-2 		http://ftp.as.harvard.edu/gcgrid/geos-chem/1yr_benchmarks/v11-01/v11-01f/MERRA2/RnPbBe/RnPbBePasv_VDIFF/output/
v11-01f
w/ GEOS-FP 		http://ftp.as.harvard.edu/gcgrid/geos-chem/1yr_benchmarks/v11-01/v11-01f/GEOSFP/RnPbBe/RnPbBePasv_VDIFF/output/
v11-01d
w/ GEOS-FP 		http://ftp.as.harvard.edu/gcgrid/geos-chem/1yr_benchmarks/v11-01/v11-01d/RnPbBe/RnPbBePasv_VDIFF/output/
v11-01b
w/ GEOS-FP 		http://ftp.as.harvard.edu/gcgrid/geos-chem/1yr_benchmarks/v11-01/v11-01b/RnPbBe/output/
v10-01
w/ GEOS-FP 		http://ftp.as.harvard.edu/gcgrid/geos-chem/1yr_benchmarks/v10-01/v10-01-public-release/RnPbBe/output/
v9-02r
w/ GEOS-FP 		http://ftp.as.harvard.edu/gcgrid/geos-chem/1yr_benchmarks/v9-02/v9-02r/geosfp/RnPbBe/output/pdf/
v9-02r
w/ GEOS-5 		http://ftp.as.harvard.edu/gcgrid/geos-chem/1yr_benchmarks/v9-02/v9-02r/geos5/RnPbBe/output/pdf/
v9-01-03e
w/ GEOS-5 		http://ftp.as.harvard.edu/gcgrid/geos-chem/1yr_benchmarks/v9-01-03/v9-01-03e/geos5/2005/RnPbBe/output/pdf/
v9-01-02
w/ GEOS-5 		http://wiki.seas.harvard.edu/geos-chem/index.php/Rn-Pb-Be_simulation#Comparison_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.

Version Met Field Year Tropospheric burden [g] Tropospheric lifetime against deposition [days] Sources [g day -1] Sinks [g day-1]
From Stratosphere From Troposphere Dry Deposition Wet Deposition Radioactive decay
Total Stratiform Convective
12.8.0
(with Luo2019 wetdep) 		GEOS-FP (72L) 2016 105.1827 3.2461 0.2690 32.1142 2.3068 30.0303 25.4236 4.6067 0.0088608
12.8.0 GEOS-FP (72L) 2016 211.6465 6.5363 0.2690 32.1142 3.9521 28.4142 19.9437 8.4705 0.0178018
12.2.0 GEOS-FP (72L) 2016 218.330 6.71344 0.236801 32.2602 3.95678 28.5218 20.0439 8.47787 0.0183735
v11-02e GEOS-FP (72L) 2016 217.941 6.71192 0.224000 32.2206 3.94971 28.4770 20.0147 8.46232 0.0183407
v11-02e GEOS-FP (72L) 2013 229.338 7.10583 0.219856 32.0661 3.90212 28.3646 19.9166 8.44793 0.0192987
v11-02e GEOS-FP 2013 229.338 7.10583 0.219864 32.0661 3.90212 28.3646 19.9166 8.44793 0.0192987
v11-02b GEOS-FP 2013 229.061 7.09725 0.219669 32.0661 3.93661 28.3299 19.8931 8.43679 0.0192754
v11-01i GEOS-FP 2013 229.335 7.10581 0.219894 32.0656 3.90206 28.3642 19.9163 8.44786 0.0192984
v11-01h GEOS-FP 2013 205.551 6.37603 0.200768 32.0656 3.32588 28.9232 22.2968 6.62642 0.0173020
v11-01f MERRA-2 2013 199.426 6.20202 0.237400 31.9437 3.26365 28.9007 21.7525 7.14814 0.0167875
v11-01f GEOS-FP 2013 204.931 6.37746 0.225323 31.9356 3.32210 28.8216 22.2060 6.61553 0.0172499
v11-01d GEOS-FP 2013 210.371 6.54296 0.225956 31.9538 3.41587 28.7451 21.9070 6.83813 0.0177696
v11-01b GEOS-FP 2013 212.655 6.60214 0.228550 31.9528 3.49478 28.6686 22.0420 6.62657 0.0179612
v10-01 GEOS-FP 2013 250.912 7.77516 0.0832825 32.2152 3.51910 28.7582 22.0207 6.73749 0.0211769
v9-02r GEOS-FP 2012/2013 247.630 7.71356 0.143133 31.9904 3.15887 28.9538 22.5351 6.41867 0.0208565
v9-02r GEOS-5 2012/2013 305.699 9.25835 0.419521 32.6109 3.42747 29.5772 20.2059 9.37127 0.0257354
v9-01-03e GEOS-5 2005 314.790 9.51050 0.128670 32.9831 3.48612 29.5991 20.8285 8.77061 0.0265495
v9-01-02 GEOS-5 2005 317.884 9.60957 0.121441 32.9831 3.49208 29.5857 19.5148 10.0709 0.0268078
v9-01-01 GEOS-5 2005 316.253 9.55568 0.129852 32.9831 3.66397 29.4223 19.4090 10.0134 0.0251665
v8-03-02 GEOS-5 2005 298.318 9.01288 0.129642 32.9831 3.21013 29.8775 21.3283 8.54923 0.0266710

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.

Version Met Field Year Tropospheric burden [g] Tropospheric lifetime against deposition [days] Sources [g day -1] Sinks [g day-1]
From Stratosphere From Troposphere Dry Deposition Wet Deposition Radioactive decay
Total Stratiform Convective
12.8.0
(with Luo2019 wetdep) 		GEOS-FP (72L) 2016 1.1882 9.5228 0.2882 0.1149 0.0052 0.1188 0.1029 0.0159 0.0154770
12.8.0 GEOS-FP (72L) 2016 2.8927 20.5842 0.2882 0.1149 0.0095 0.1305 0.1047 0.0258 0.0376572
12.2.0 GEOS-FP (72L) 2016 3.55540 24.5959 0.0541444 0.136303 0.00952537 0.134645 0.108871 0.0257736 0.0462768
v11-02e GEOS-FP (72L) 2016 3.56036 24.6000 0.0543652 0.136303 0.00955045 0.134776 0.108970 0.0258063 0.0463413
v11-02e GEOS-FP (72L) 2013 3.50286 24.9516 0.0529614 0.132687 0.0102709 0.129784 0.103733 0.0260514 0.0455928
v11-02e GEOS-FP 2013 3.51047 24.9816 0.0531919 0.132687 0.0102796 0.129907 0.103831 0.0260759 0.0456918
v11-02b GEOS-FP 2013 3.51002 24.9773 0.0531920 0.132688 0.0103364 0.129856 0.103796 0.0260605 0.0456861
v11-01i GEOS-FP 2013 3.51044 24.9815 0.0531920 0.132685 0.0102795 0.129907 0.103831 0.0260760 0.0456914
v11-01h GEOS-FP 2013 3.27337 22.7988 0.0531059 0.132685 0.00626941 0.136914 0.124153 0.0127610 0.0426082
v11-01f MERRA-2 2013 3.12435 21.2728 0.0538848 0.133202 0.00650753 0.139910 0.124784 0.0151255 0.0406699
v11-01f GEOS-FP 2013 3.27720 22.8066 0.0531204 0.132842 0.00628201 0.137021 0.124239 0.0127822 0.0426591
v11-01d GEOS-FP 2013 3.32564 23.2523 0.0530363 0.132914 0.00664940 0.135989 0.122347 0.0136424 0.0433123
v11-01b GEOS-FP 2013 3.33530 23.3408 0.0530463 0.132914 0.00698390 0.135539 0.1228950 0.0126441 0.0434378
v10-01 GEOS-FP 2013 3.98942 30.1194 0.0512072 0.132977 0.00794288 0.124298 0.1101450 0.0141529 0.0519433
v9-02r GEOS-FP 2012/2013 3.41039 25.9787 0.0630964 0.112349 0.00782526 0.123206 0.1093560 0.0138500 0.0444134
v9-02r GEOS-5 2012/2013 3.49564 27.5376 0.0674867 0.104750 0.00881422 0.117906 0.0844566 0.0334494 0.0455165
v9-01-03e GEOS-5 2005 4.37787 34.6750 0.0504472 0.132552 0.00882144 0.117156 0.0858211 0.0393817 0.0570217
v9-01-02 GEOS-5 2005 4.39653 34.8814 0.0504253 0.132552 0.00936374 0.116350 0.0769681 0.0393817 0.0572633
v9-01-01 GEOS-5 2005 4.39407 34.8514 0.0504328 0.132552 0.00969345 0.116060 0.0767926 0.0392671 0.0572312
v8-03-02 GEOS-5 2005 4.31961 33.9930 0.0504585 0.132552 0.00808056 0.118666 0.0846774 0.0339885 0.0562636

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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