Mean OH concentration

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Revision as of 02:17, 13 August 2023 by Melissa Payer (Talk | contribs) (Plot of mean OH evolution)

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On this page we track the evolution of the mean OH concentration in GEOS-Chem. This value is an indicator of how "hot" the chemistry is. Please also see the related topic about the methyl chloroform lifetime in GEOS-Chem.

Computation of the mean OH diagnostic

Routine DO_DIAG_OH (in module GeosCore/diag_oh_mod.F) sums up the tropospheric air mass and mass-weighted OH mass after each call to the chemistry solver. The summing happens in these lines of code:

     ! Skip non-chemistry boxes
     IF ( .not. State_Met%InChemGrid(I,J,L) ) CYCLE

     ! Dry air density [molec/cm3]
     ! Cast to REAL*8 to avoid underflow
     AIRDENS_8       = State_Met%AIRNUMDEN(I,J,L)

     ! Box volume [cm3]
     ! Cast to REAL*8 to avoid underflow
     VOLUME_8        = State_Met%AIRVOL(I,J,L) * 1e+6_fp

     ! Sum air mass term into AIR_MASS array
     XAIRMASS        = AIRDENS_8         * VOLUME_8
     AIR_MASS(I,J,L) = AIR_MASS(I,J,L)   + XAIRMASS

     ! Sum OH mass term into OH_MASS array
     XOHMASS         = State_Chm%Species(I,J,L,id_OH) * XAIRMASS
     OH_MASS(I,J,L)  = OH_MASS(I,J,L)    + XOHMASS

where the arrays contain the following quantities:

  I,J,L                           = 3-D array indices
  AIRDENS_8                       = air density [molec/cm3]
  VOLUME_8                        = grid box volume [cm3]
  AIR_MASS(I,J,L)                 = air mass [molec air]
  State_Chm%Species(I,J,L,id_OH)  = OH concentration [molec OH/cm3]  
  OH_MASS(I,J,L)                  = mass-weighted OH = OH mass * air mass [molec OH/cm3 * molec air]

After the GEOS-Chem simulation finishes, the mean OH value is printed out in subroutines PRINT_MEAN_OH (in module GeosCore/diag_oh_mod.F):

  ! Total Mass-weighted OH [molec OH/cm3] * [molec air]
  SUM_OHMASS = SUM( OH_MASS )

  ! Atmospheric air mass [molec air]
  SUM_MASS   = SUM( AIR_MASS ) 
         
  ! Divide OH [molec OH/cm3 * molec air] by [molec air] and report as [1e5 molec/cm3]
  OHCONC = ( SUM_OHMASS / SUM_MASS ) / 1d5

  ! Write value to log file
  WRITE( 6, '(/,a)' ) REPEAT( '=', 79 ) 
  WRITE( 6, *       ) 'ND23: Mass-Weighted OH Concentration'
  WRITE( 6, *       ) 'Mean OH = ', OHCONC, ' [1e5 molec/cm3]' 
  WRITE( 6, '(  a)' ) REPEAT( '=', 79 ) 
        

Typical values are around 105 or 115 molec/cm3.

--Bob Yantosca (talk) 19:43, 29 March 2018 (UTC)

Evolution of mean OH in GEOS-Chem

Plot of mean OH evolution

Here is a plot of the mean OH concentration from GEOS-Chem 1-year benchmark simulations through version 12.8.0 (released 04 May 2020). The mean OH is an indicator how the chemistry mechanism is performing. Typical values are 10–12 x 105 molecules cm-1.

GC Mean OH 12.8.0.png

--Melissa Sulprizio (talk) 02:17, 13 August 2023 (UTC)

Mean OH in GEOS-Chem 12

The following table chronicles the evolution of the mean OH value from several different GEOS-Chem simulations. All benchmark simulations were conducted at 4° x 5° resolution unless noted otherwise.

Benchmark Met Fields & Year Mean OH
[105 molec cm-3]
Change from
prev. version
[105 molec cm-3]
Important updates in this benchmark simulation References
12.8.0 GEOS-FP 2016 10.613 +0.108
(+1.02%)
Updates introduced in 12.8.0:

Updates introduced in 12.7.0:

12.6.0 GEOS-FP 2016 10.505 -0.797
(-7.05%)
Updates introduced in 12.6.0:

Updates introduced in 12.5.0:

12.4.0 GEOS-FP 2016 11.302 -.346
(-2.97%)
Updates introduced in 12.4.0:

Updates introduced in 12.3.0:

Updates introduced in 12.2.0:

Updates introduced in 12.1.0:

12.0.0 GEOS-FP 2016 11.648 +0.116
(+0.101%)
Updates introduced in 12.0.0

Mean OH in GEOS-Chem v11

The following table chronicles the evolution of the mean OH value from several different GEOS-Chem simulations. All benchmark simulations were conducted at 4° x 5° resolution unless noted otherwise.

Benchmark Met Fields & Year Mean OH
[105 molec cm-3]
Change from
prev. version
[105 molec cm-3]
Important updates in this benchmark simulation References
v11-02f-Run0 GEOS-FP 2016 11.532 -0.009
(-0.077%)
Updates introduced in v11-02f:
v11-02e-Run1 GEOS-FP 2016 11.541 -0.145
(-1.24%)
Same as v11-02e-Run0, but
  • Use GEOS-FP 2016 meteorology instead of GEOS-FP 2013 meteorology
v11-02e-Run0 GEOS-FP 2016 11.686 -0.171
(-1.44%)
Updates introduced in v11-02e:
v11-02d-Run2 GEOS-FP 2013 11.857 0.195
(1.672%)
Everything in v11-02d-Run0, plus:
v11-02d-Run0 GEOS-FP 2013 11.662 0.066
(0.569%)
Updates introduced in v11-02d:
v11-02c-Run0 GEOS-FP 2013 11.596 -0.233
(-1.970%)
Updates introduced in v11-02c:
v11-02a-Run1 GEOS-FP 2013 11.829 .079
(0.672%)
Same as in v11-02a-Run0, but:
  • Partitioning of NOx biomass burning emissions directly to PAN and HNO3 has been removed
v11-02a-Run0 GEOS-FP 2013 11.750 -0.251
(-2.09%)
Updates introduced in v11-02a:
v11-01-public-release-Run0 GEOS-FP 2013 12.001 -0.003
(-0.025%)
Updates introduced in v11-01 public release:
v11-01k-Run0 GEOS-FP 2013 12.004 -0.065
(-.538%)
Updates introduced in v11-01h:

Updates introduced in v11-01i:

Updates introduced in v11-01j:

Updates introduced in v11-01k:

v11-01g-Run0 GEOS-FP 2013 12.069 0.025
(0.207%)
Updates introduced in v11-01g:
v11-01f-geosfp-Run0 GEOS-FP 2013 12.044 0.033
(0.275%)
Updates introduced in v11-01e:

Updates introduced in v11-01f:

v11-01d-Run1 GEOS-FP 2013 12.011 0.011
(0.0916%)
Updates introduced in v11-01c:

Updates introduced in v11-01d:

v11-01b-Run0 GEOS-FP 2013 12.000 0.277
(2.30%)
Updates introduced in v11-01a:

Updates introduced in v11-01b:

--Bob Yantosca (talk) 18:12, 29 March 2018 (UTC)

Mean OH in GEOS-Chem v10

The following table chronicles the evolution of the mean OH value from several different GEOS-Chem simulations. All benchmark simulations were conducted at 4° x 5° resolution unless noted otherwise.

Benchmark Met Fields & Year Mean OH
[105 molec cm-3]
Change from
prev. version
[105 molec cm-3]
Important updates in this benchmark simulation References
v10-01i-Run0 GEOS-FP 2013 11.125 0.033
(0.298%)
v10-01h-Run0 GEOS-FP 2013 11.092 -0.751
(-6.341%)
v10-01e-Run1 GEOS-FP 2013 11.843 -0.042
(-0.353%)
v10-01c-Run1 GEOS-FP 2013 11.885 -0.665
(-5.299%)
v10-01c-Run0 GEOS-FP 2013 12.550 -0.139
(-1.095%)

--Bob Yantosca (talk) 18:12, 29 March 2018 (UTC)

Mean OH in GEOS-Chem v9

The following table chronicles the evolution of the mean OH value from several different GEOS-Chem simulations. All benchmark simulations were conducted at 4° x 5° resolution unless noted otherwise.

Benchmark Met Fields & Year Mean OH
[105 molec cm-3]
Change from
prev. version
[105 molec cm-3]
Important updates in this benchmark simulation References
v9-02r-geosfp-Run1 GEOS-FP 2013 12.689 0.300 (2.421%) *Global simulations with GEOS-FP data product from GMAO
v9-02r-geosfp-Run0 GEOS-FP 2013 12.389 -0.537 (-4.154%)
v9-02r-geos5-Run0 GEOS-5.1.0 2005 12.926 0.356
(2.832%)
v9-02l-Run0 GEOS-5.1.0 2005 12.570 0.332
(2.713%)
v9-02j-Run0 GEOS-5.1.0 2005 12.238 -0.234
(-1.876%)
v9-02g-Run0 GEOS-5.1.0 2005 12.472 0.969
(8.424%)
v9-02f-Run0 GEOS-5.1.0 2005 11.503 0.079
(0.692%)
v9-02b-Run0 GEOS-5.1.0 2005 11.424 0.068
(0.599%)
v9-01-03r-Run1 GEOS-5.1.0 2005 11.356 -0.502
(-4.233%)
v9-01-03r-Run0 GEOS-5.1.0 2005 11.858 -0.077
(-0.645%)
v9-01-03e-Run0 GEOS-5.1.0 2005 11.935 -0.397
(-3.219%)
v9-01-02-Run1 GEOS-5.1.0 2005 12.332 +0.099
(+0.809%)
v9-01-02-Run0 GEOS-5.1.0 2005 12.233 -0.009
(-0.074%)
v9-01-01-Run1 GEOS-5.1.0 2005 12.242 +0.377
(+3.177%)
v9-01-01-Run0 GEOS-5.1.0 2005 11.865 +0.798
(+7.2%)

--Bob Yantosca (talk) 18:12, 29 March 2018 (UTC)

Mean OH in GEOS-Chem v8

The following table chronicles the evolution of the mean OH value from several different GEOS-Chem simulations. All benchmark simulations were conducted at 4° x 5° resolution unless noted otherwise.

Benchmark Met Fields & Year Mean OH
[105 molec cm-3]
Change from
prev. version
[105 molec cm-3]
Important updates in this benchmark simulation References
v8-02-04-Run2 GEOS-5.1.0 2005 11.067 +0.019
(+0.17%)
  • Linoz stratospheric ozone chemistry used instead of SYNOZ scheme
v8-02-04-Run1 GEOS-5.1.0 2005 11.048 +0.598
(+5.72%)
  • MEGAN hybrid model with MODIS-derived LAI
v8-02-04-Run0 GEOS-5.1.0 2005 10.450 -1.362
(-11.53%)
  • MEGAN hybrid model with AVHRR-derived LAI
  • EPA/NEI2005 emissions
  • Non-local PBL mixing scheme
v8-02-01-Run0 GEOS-5.1.0 2005 11.812 +0.713
(+6.42%)
  • Updated chemical mechanism: globchem.dat
  • Updated photolysis rxn rates: jv_spec.dat, ratj.d
NOTE: there was a bug in near IR photolysis of HNO4 and HCHO in the jv_spec.dat and ratj.d files. This was finally resolved in v8-02-04. We recommend all users of v8-02-01, v8-02-02, and v8-02-03 to use these updated jv_spec.dat and ratj.d files.
v8-01-04-Run2 GEOS-5.1.0 2005 11.099 +0.805
(+7.82%)
v8-01-04-Run1 GEOS-5.0.1 2005 10.294 -0.395
(-3.69%)
  • Various emissions updates with regional overwrites
  • Aaron van Donkelaar et al scale factors for 2005
  • Switched from linear to random cloud overlap in FAST-J
v8-01-04-Run0 GEOS-5.0.1 2005 10.689 -1.351
(-11.22%)
v8-01-01-Run1 GEOS-5.0.1 2005 12.040 +0.034
(+0.28%)
  • Switched aerosol thermodynamical equilibrium scheme from ISORROPIA I to RPMARES
v8-01-01-Run0 GEOS-5.0.1 2005 12.006 -0.141
(-1.16%)
  • First simulation with GEOS-5 met data

--Bob Yantosca (talk) 18:11, 29 March 2018 (UTC)

Additional information for GEOS-Chem v8

--Bob Yantosca (talk) 19:12, 29 March 2018 (UTC)

Mean OH in GEOS-Chem v7

The following table chronicles the evolution of the mean OH value from several different GEOS-Chem simulations. All benchmark simulations were conducted at 4° x 5° resolution unless noted otherwise.

Benchmark Met Fields & Year Mean OH
[105 molec cm-3]
Change from
prev. version
[105 molec cm-3]
Important updates in this benchmark simulation References
v7-04-13-Run GEOS-4 2005 12.147 -0.669
(-5.22%)
v7-04-12-Run2 GEOS-4 2005 12.816 +1.053
(+8.95%)
  • Original non-near-land OTD/LIS local scaling
v7-04-12-Run1 GEOS-4 2005 11.763 -0.68
(-5.5%)
  • Ancient lightning scheme
v7-04-02-MEGAN GEOS-4 2001 12.44 -0.11
(-0.87%)
  • First benchmark w/ MEGAN biogenic emissions
v7-04-02-NOMEGAN GEOS-4 2001 12.55 +0.01
(+0.08%)
  • Switched fossil fuel scale year from 1995 to 1998
  • Last benchmark w/ the older GEIA biogenic emissions
v7-04-02-Base GEOS-4 2001 12.54 +0.67
(+5.6%)
  • 43 tracer simulation (no secondary organic aerosols)
  • Last 1-yr benchmark with fossil fuel scale year = 1995
v7-02-03-Run1 GEOS-4 2001 11.87 +1.39
(+13.26%)
  • Secondary organic aerosols (50 tracers)
  • GEOS-4 met fields
v7-02-03-Run0 GEOS-3 2001 10.48 ---
  • Secondary organic aerosols (50 tracers)
  • GEOS-3 2001

--Bob Yantosca (talk) 18:11, 29 March 2018 (UTC)

Additional information for GEOS-Chem v7

--Bob Yantosca (talk) 19:13, 29 March 2018 (UTC)