detailed_halogen_and_DMS_chemistry.md

Adding detailed halogen and DMS chemistry to CB6r3

Golam Sarwar, U.S. Environmental Protection Agency

Brief Description

Detailed chemistry for the halogens (bromine and iodine) was incorporated into the CB05 chemical mechanism in a previous release of CMAQ. In CMAQv5.3, the detailed halogen chemistry is extended for CB6r3. It contains 38 gas-phase reactions and 4 heterogeneous reactions for bromine chemistry, and 44 gas-phase reactions and 10 heterogeneous reactions for iodine chemistry. Dimethyl sulfide (DMS) chemistry is also combined with CB6r3 and implemented into CMAQv5.3. It contains 7 gas-phase reactions involving DMS and oxidants. The combined chemical mechanism containing CB6r3, detailed halogen and DMS chemistry is named as CB6r3m. The halogen chemistry is more beneficial in the hemispheric CMAQ model where there is a larger influence on the intercontinental transport over oceans. However, it can also be used in the regional version of the model.

Significance and Impact

Model sensitivity runs were completed with CB6r3 (without detailed halogen and DMS chemistry) and CB6r3m (with detailed halogen and DMS chemistry) over the Northern Hemisphere for three months in 2015 (October-December). It reduces ozone by 3-14 ppbV (Figure 1) and increases sulfur dioxide by 20-160 pptV (Figure 2) and sulfate by 0.1-0.8 μg m 3 (Figure 3) over much of the sea water. It reduces ozone and increases sulfate over land by much smaller margins than over sea water.

Figure 1: Impact of halogen chemistry on ozone (three-month average).

Figure 2: Impact of halogen chemistry on sulfur dioxide (three-month average).

Figure 3: Impact of halogen chemistry on sulfate (three-month average).

Affected Files

• CCTM/scripts/bldit_cctm.csh
• CCTM/src/MECHS/cb6r3m_ae7_kmtbr/AE_cb6r3m_ae7_kmtbr.nml
• CCTM/src/MECHS/cb6r3m_ae7_kmtbr/CSQY_DATA_cb6r3m_ae7_kmtbr
• CCTM/src/MECHS/cb6r3m_ae7_kmtbr/GC_cb6r3m_ae7_kmtbr.nml
• CCTM/src/MECHS/cb6r3m_ae7_kmtbr/NR_cb6r3m_ae7_kmtbr.nml
• CCTM/src/MECHS/cb6r3m_ae7_kmtbr/RXNS_DATA_MODULE.F90
• CCTM/src/MECHS/cb6r3m_ae7_kmtbr/RXNS_FUNC_MODULE.F90
• CCTM/src/MECHS/cb6r3m_ae7_kmtbr/SpecDef_Dep_cb6r3m_ae7_kmtbr.txt
• CCTM/src/MECHS/cb6r3m_ae7_kmtbr/SpecDef_cb6r3m_ae7_kmtbr.txt
• CCTM/src/MECHS/cb6r3m_ae7_kmtbr/mech_cb6r3m_ae7_kmtbr.def
• CCTM/src/aero/aero6/AEROSOL_CHEMISTRY.F
• CCTM/src/aero/aero6/AERO_DATA.F
• CCTM/src/aero/aero6/SOA_DEFN.F
• CCTM/src/cloud/acm_ae6/hlconst.F
• CCTM/src/cloud/acm_ae7_kmtbr/AQ_DATA.F
• CCTM/src/cloud/acm_ae7_kmtbr/acmcld.f
• CCTM/src/cloud/acm_ae7_kmtbr/aq_map.F
• CCTM/src/cloud/acm_ae7_kmtbr/aqchem_Function.F90
• CCTM/src/cloud/acm_ae7_kmtbr/aqchem_Global.F90
• CCTM/src/cloud/acm_ae7_kmtbr/aqchem_Initialize.F90
• CCTM/src/cloud/acm_ae7_kmtbr/aqchem_Integrator.F90
• CCTM/src/cloud/acm_ae7_kmtbr/aqchem_Jacobian.F90
• CCTM/src/cloud/acm_ae7_kmtbr/aqchem_JacobianSP.F90
• CCTM/src/cloud/acm_ae7_kmtbr/aqchem_LinearAlgebra.F90
• CCTM/src/cloud/acm_ae7_kmtbr/aqchem_Model.F90
• CCTM/src/cloud/acm_ae7_kmtbr/aqchem_Parameters.F90
• CCTM/src/cloud/acm_ae7_kmtbr/aqchem_Precision.F90
• CCTM/src/cloud/acm_ae7_kmtbr/aqchem_Rates.F90
• CCTM/src/cloud/acm_ae7_kmtbr/aqchem_kmt.F90
• CCTM/src/cloud/acm_ae7_kmtbr/cldproc_acm.F
• CCTM/src/cloud/acm_ae7_kmtbr/convcld_acm.F
• CCTM/src/cloud/acm_ae7_kmtbr/getalpha.F
• CCTM/src/cloud/acm_ae7_kmtbr/hlconst.F
• CCTM/src/cloud/acm_ae7_kmtbr/indexn.f
• CCTM/src/cloud/acm_ae7_kmtbr/opwdep.F
• CCTM/src/cloud/acm_ae7_kmtbr/rescld.F
• CCTM/src/cloud/acm_ae7_kmtbr/scavwdep.F
• CCTM/src/depv/m3dry/DEPVVARS.F
• CCTM/src/emis/emis/BIOG_EMIS.F
• CCTM/src/emis/emis/EMIS_DEFN.F
• CCTM/src/emis/emis/MGEMIS.F
• CCTM/src/emis/emis/SSEMIS.F
• CCTM/src/gas/ebi_cb6r3m_ae7_kmtbr/DEGRADE_SETUP_TOX.F
• CCTM/src/gas/ebi_cb6r3m_ae7_kmtbr/degrade.F
• CCTM/src/gas/ebi_cb6r3m_ae7_kmtbr/degrade_data.F
• CCTM/src/gas/ebi_cb6r3m_ae7_kmtbr/final_degrade.F
• CCTM/src/gas/ebi_cb6r3m_ae7_kmtbr/find_degraded.F
• CCTM/src/gas/ebi_cb6r3m_ae7_kmtbr/hrdata_mod.F
• CCTM/src/gas/ebi_cb6r3m_ae7_kmtbr/hrdriver.F
• CCTM/src/gas/ebi_cb6r3m_ae7_kmtbr/hrg1.F
• CCTM/src/gas/ebi_cb6r3m_ae7_kmtbr/hrg2.F
• CCTM/src/gas/ebi_cb6r3m_ae7_kmtbr/hrg3.F
• CCTM/src/gas/ebi_cb6r3m_ae7_kmtbr/hrg4.F
• CCTM/src/gas/ebi_cb6r3m_ae7_kmtbr/hrinit.F
• CCTM/src/gas/ebi_cb6r3m_ae7_kmtbr/hrprodloss.F
• CCTM/src/gas/ebi_cb6r3m_ae7_kmtbr/hrrates.F
• CCTM/src/gas/ebi_cb6r3m_ae7_kmtbr/hrsolver.F
• CCTM/src/gas/ebi_cb6r3m_ae7_kmtbr/init_degrade.F
• CCTM/src/vdiff/acm2_m3dry/ASX_DATA_MOD.F
• UTIL/inline_phot_preproc/photolysis_CSQY_data/COHBR_JPL2010
• UTIL/inline_phot_preproc/photolysis_CSQY_data/IBR_IUPAC10
• UTIL/inline_phot_preproc/photolysis_CSQY_data/IONO2_06

References

1. Sarwar, G.; Gantt, B.; Foley, K.; Fahey, K.; Spero T. L.; Kang, D., Mathur, Rohit M., Hosein F.; Xing, J.; Sherwen, T.; Saiz-Lopez, A., 2019: Influence of bromine and iodine chemistry on annual, seasonal, diurnal, and background ozone: CMAQ simulations over the Northern Hemisphere, Atmospheric Environment, 213, 395-404.
2. Sarwar, G., Gantt, B.; Schwede, D.; Foley, K.; Mathur, R.; Saiz-Lopez, A. Impact of enhanced ozone deposition and halogen chemistry on tropospheric ozone over the Northern Hemisphere, Environmental Science & Technology, 2015, 49(15):9203-9211.
3. Saiz-Lopez, A.; Fernandez, R. P.; Ordóñez, C.; Kinnison, D. E.; Gómez Martín, J. C.; Lamarque, J.-F.; Tilmes, S. Iodine chemistry in the troposphere and its effect on ozone. Atmospheric Chemistry and Physics, 2014, 14, 13119-13143.
4. Fernandez, R. P.; Salawitch, R. J.; Kinnison, D. E.; Lamarque, J.-F.; Saiz-Lopez, A. Bromine partitioning in the tropical tropopause layer: implications for stratospheric injection. Atmospheric Chemistry and Physics, 2014, 14, 13391-13410.
5. Sherwen, T., Evans, M. J., Carpenter, L. J., Andrews, S. J., Lidster, R. T., Dix, B., Koenig, T. K., Sinreich, R., Ortega, I., Volkamer, R., Saiz-Lopez, A., Prados-Roman, C., Mahajan, A. S., and Ordóñez, C.: Iodine's impact on tropospheric oxidants: a global model study in GEOS-Chem. Atmospheric Chemistry and Physics, 2016, 16, 1161-1186.
6. Sherwen, T., Schmidt, J. A., Evans, M. J., Carpenter, L. J., Großmann, K., Eastham, S. D., Jacob, D. J., Dix, B., Koenig, T. K., Sinreich, R., Ortega, I., Volkamer, R., Saiz-Lopez, A., Prados-Roman, C., Mahajan, A. S., and Ordóñez, C. Global impacts of tropospheric halogens (Cl, Br, I) on oxidants and composition in GEOS-Chem, Atmospheric Chemistry and Physics, 2016, 16, 12239-12271.
7. Yarwood, Y., Sakulyanontvittaya, T., Nopmongcol, O., and Koo, K. Ozone Depletion by Bromine and Iodine over the Gulf of Mexico, Final Report for the Texas Commission on Environmental Quality, November 2014.
8. Sarwar, G., J. Xing, K. Fahey, K. Foley, D. Wong, R. Mathur, C. M. Gan, B. Gant, H. Simon, 2016. Dimethylsulfide chemistry: seasonal and spatial impacts on sulfate, Chapter 55, Clemens Mensink, George Kallos (ed.), Air Pollution Modeling and its Application XXV. Springer, 347-352.

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Internal Records

Relevant Pull Requests:

PR #362

PR #433

Commit IDs:

e071d336de4e98b37e7d0d7b23b73f81f4daf79b 66f076fbb441e4d75e9ee55821da1cd63bf4a4d9 4e95eac60e9c78b27faf0c5e6d1c51b0b15cf7db 81edc0a978469bf9ea4e917f9de592921431134d

2d7d094b1cfa8b5432950d3719e0ce94082eba50

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