.. _transport-sim: ########################### TransportTracers simulation ########################### .. _transport-sim-overview: ======== Overview ======== The :program:`GEOS-Chem Rn-Pb-Be simulation` was based on that of the old Harvard/GISS CTM model. In version 12.2.0, this 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 :program:`TransportTracers` 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. .. _transport-sim-references: ========== References ========== #. :cite:t:`Liu_et_al._2001` #. :cite:t:`Jacob_et_al._1997` #. :cite:t:`Koch_et_al._1996` #. :cite:t:`Koch_Rind_1998` #. :cite:t:`Lal_Peters_1967` .. _transport-sim-species: =============== List of species =============== .. _transport-species-rn222: Rn222 ----- - **Description:** Radon-222 isotope - **Purpose:** Used to evaluate convection over land and strat-trop exchange. - **Formula:** Rn222 - **Molecular weight (g):** 222.0 - **Source:** Emitted naturally from soils based on `Zhang et al., 2021 `_. - **Sinks:** Radioactive decay into :ref:`transport-species-pb210` with a half-life of 3.83 days (cf `Liu et al., 2021 `_). .. _transport-species-pb210: Pb210 ----- - **Description:** Lead-210 isotope - **Purpose:** Used to evaluate wet scavenging and transport. - **Formula:** Pb210 - **Molecular weight (g):** 210.0 - **Source:** Radioactive decay from :ref:`transport-species-rn222`. - **Sinks:** #. Radioactive decay with a half-life of 22.3 years (Liu et al., 2001). #. Wet deposition #. Dry deposition .. _transport-species-pb210s: Pb210s ------ - **Description:** Lead-210 isotope stratospheric-source tracer - **Purpose:** Used to evaluate strat-trop exchange. - All other properties are identical to :ref:`transport-species-pb210`. .. _transport-species-be7: Be7 --- - **Description:** Beryllium-7 isotope - **Purpose:** Used to evaluate wet scavenging and strat-trop exchange. - **Formula:** Be7 - **Molecular weight (g):** 7.0 - **Source:** Produced by cosmic rays as described in `Lal and B. Peters, 1967 `_, with the following modifications (cf. Liu et al, 2001): #. Use 1900 disintegrations / g air / s (instead of 3000) at 0 hPa altitude and 70°S latitude. #. The original Lal & Peters data ended at 70°S. The values at 70°S were copied to 80°S and 90°S at all levels. - **Sinks:** #. Radioactive decay with a half-life of 53.3 days (Liu et al., 2001). #. Wet deposition #. Dry deposition .. _transport-species-be7s: Be7s ---- - **Description:** Beryllium-7 isotope stratospheric-source tracer - **Purpose:** Used to evaluate wet scavenging and strat-trop exchange. - All other properties are the same as for :ref:`transport-species-be7`. .. _transport-species-be10: Be10 ---- - **Description:** Beryllium-10 isotope - **Purpose:** Used to evaluate wet scavenging and strat-trop exchange. - **Formula:** Be7 - **Molecular weight (g):** 7.0 - **Source:** Identical to :ref:`transport-species-be7`. - **Sinks:** #. Radioactive decay with a half-life of :math:`5.84 \times 10^{8}` days (Koch and Rind 1998). #. Wet deposition #. Dry deposition .. _transport-species-be10s: Be10s ----- - **Description:** Beryllium-10 isotope stratospheric-source tracer - **Purpose:** Used to evaluate wet scavenging and strat-trop exchange. - All other properties are the same as for :ref:`transport-species-be10`. .. _transport-species-aoa: aoa --- - **Description:** Age of air uniform source tracer - **Purpose:** Used for evaluating residual circulation and mixing. - **Molecular weight (g):** 1.0 - **Source:** Increases by a value of 1 each emissions timestep. - **Sink:** At the surface. .. _transport-species-aoabl: aoa_bl ------ - **Description:** Age of air uniform source tracer with sink restricted to the boundary layer - **Purpose:** Used for evaluating residual circulation and mixing. - **Molecular weight (g):** 1.0 - **Source:** Increases by a value of 1 each emissions timestep. - **Sink:** In the boundary layer. .. _transport-species-aoanh: aoa_nh ------ - **Description:** Age of air uniform source tracer with sink restricted to a zone in the Northern Hemisphere - **Purpose:** Used for evaluating residual circulation and mixing. - **Molecular weight (g):** 1.0 - **Source:** Increases by a value of 1 each emissions timestep. - **Sink:** At 30°N - 50°N. .. _transport-species-ch3i: CH3I ---- - **Description:** Methyl iodide - **Purpose:** Used to evaluate marine convection - **Formula:** CH3I - **Molecular weight (g):** 141.94 - **Source:** Emissions over the oceans of 1 molec/cm2/s - **Sink:** 5-day e-folding lifetime .. _transport-species-co25: CO_25 ----- - **Description:** Anthropogenic CO 25 day tracer - **Formula:** CO - **Molecular weight (g):** 28.01 - **Source:** Anthropogenic emissions - **Sink:** 25-day e-folding lifetime .. _transport-species-co50: CO_50 ----- - **Description:** Anthropogenic CO 50 day tracer - **Formula:** CO - **Molecular weight (g):** 28.01 - **Source:** Anthropogenic emissions - **Sink:** 50-day e-folding lifetime .. _transport-species-e90: e90 --- - **Description:** Constant burden 90 day tracer - **Molecular weight (g):** 1.0 - **Source:** Emitted globally at the surface such that the mixing ratio is maintained at 100 ppbv - **Sink:** 90-day e-folding lifetime .. _transport-species-e90n: e90_n ----- - **Description:** Constant burden Northern Hemisphere 90 day tracer - **Molecular weight (g):** 1.0 - **Source:** Emitted at the surface such that the mixing ratio is maintained at 100 ppbv. Emissions source is restricted to 40°N - 90°N. - **Sink:** 90-day e-folding lifetime .. _transport-species-e90s: e90_s ----- - **Description:** Constant burden Southern Hemisphere 90 day tracer - **Molecular weight (g):** 1.0 - **Source:** Emitted at the surface such that the mixing ratio is maintained at 100 ppbv. Emissions source is restricted to 90°S - 40°S. - **Sink:** 90-day e-folding lifetime .. _transport-species-nh5: nh_5 ---- - **Description:** Northern Hemisphere 5 day tracer - **Molecular weight (g):** 1.0 - **Source:** Constant source of 100 ppbv at latitudes 30°N - 50°N - **Sink:** 5-day e-folding lifetime .. _transport-species-nh50: nh_50 ----- - **Description:** Northern Hemisphere 50 day tracer - **Molecular weight (g):** 1.0 - **Source:** Constant source of 100 ppbv at latitudes 30°N - 50°N - **Sink:** 50-day e-folding lifetime .. _transport-species-pasv: PassiveTracer ------------- - **Description:** Passive tracer for mass conservation evaluation - **Purpose:** Used to evaluate mass conservation in transport - **Molecular weight (g):** 1.0 - **Source:** None - **Sink:** None .. _transport-species-sf6: SF6 --- - **Description:** Sulfur hexafluoride - **Purpose**: Used to evaluate inter-hemispheric transport of anthropogenic emissions - **Formula:** SF6 - **Molecular weight (g):** 146.06 - **Source:** Anthropogenic emissions - **Sink:** None .. _transport-species-st8025: st80_25 ------- - **Description:** Stratosphere source 25 day tracer - **Molecular weight (g):** 1.0 - **Source:** Constant source of 200 ppbv above 80 hPa - **Sink:** 25-day e-folding lifetime