ClOxCycle

{
  "reference": {
    "notes": "source_ref: GasChem.jl@8c12c048482b515fb8eb2110bf8ab4b4f4e71309:src/StratosphericChemistry.jl:272\n\nUpstream `ClOxCycle` is an MTK `@component` with 12 `@constants` (Arrhenius pre-factors and activation temperatures for five binary channels plus the termolecular ClO + NO2 + M reference), 9 `@parameters` (T, M, j_ClONO2, and the six fixed-bath concentrations CH4, O, O3, NO, NO2, OH), and 6 `@variables` (4 time-indexed states Cl, ClO, HCl, ClONO2 + 2 algebraic family sums ClOx, Cly). All 6 equations preserved verbatim: 4 ODEs (D(Cl), D(ClO), D(HCl), D(ClONO2)) + 2 algebraic (ClOx ~ Cl + ClO, Cly ~ Cl + ClO + HCl + ClONO2). The upstream structural test (test/StratosphericChemistry_test.jl:71-81) asserts `length(equations(sys)) == 6` and that Cl, ClO, ClONO2, ClOx appear as states — both preserved here.\n\nUpstream `@constants` are encoded as parameters with their upstream SI default values, matching the convention used by sibling migrations in this rig (snow_thermal.esm encodes physical constants as parameters with default; diameter_growth.esm encodes R_gas, D_diff similarly). Rate coefficients are written inline in the equations as `A * exp(C / T)` (binary) and `A * (T_ref / T)^3.4` (termolecular ClO + NO2 + M) per Seinfeld & Pandis Table B.1/B.2 (pp. 162-167). CGS→SI conversion factors (cm³/molec/s × 1e-6; cm⁶/molec²/s × 1e-12) are folded into the `_A` defaults: e.g. upstream Cl + O3 pre-factor 2.3e-11 cm³/molec/s → 2.3e-17 m³/s.\n\nCly conservation: the upstream `Cly Conservation (ClOx Cycle)` test (test/StratosphericChemistry_test.jl:266-290) asserts that Cly = Cl + ClO + HCl + ClONO2 is conserved to rtol = 1e-6 over a 1 s integration. This is structurally exact for this component — summing the four ODEs:\n\n    D(Cl)     = -k_Cl_O3·Cl·O3 + k_ClO_O·ClO·O + k_ClO_NO·ClO·NO - k_Cl_CH4·Cl·CH4 + k_OH_HCl·OH·HCl + j_ClONO2·ClONO2\n    D(ClO)    = +k_Cl_O3·Cl·O3 - k_ClO_O·ClO·O - k_ClO_NO·ClO·NO - k_ClO_NO2_M·ClO·NO2·M\n    D(HCl)    = +k_Cl_CH4·Cl·CH4 - k_OH_HCl·OH·HCl\n    D(ClONO2) = +k_ClO_NO2_M·ClO·NO2·M - j_ClONO2·ClONO2\n    Σ         = 0\n\nso D(Cly) ≡ 0 analytically and any observed drift in Cly is integrator roundoff — this is why the upstream test uses rtol = 1e-6 over 1 s while internal solver tolerances run at abstol = 1e-12, reltol = 1e-12. The migration preserves this exact conservation structure.\n\nClOx (= Cl + ClO) is NOT conserved: D(ClOx) = -k_Cl_CH4·Cl·CH4 + k_OH_HCl·OH·HCl + j_ClONO2·ClONO2 - k_ClO_NO2_M·ClO·NO2·M, the four-channel exchange between the active ClOx pair and the reservoir species HCl and ClONO2. The Cl + CH4 / OH + HCl pair shuttles between ClOx and HCl; the ClO + NO2 + M / ClONO2 + hν pair shuttles between ClOx and ClONO2.\n\nTolerance rationale (model-level rel=1e-6): reference trajectories from upstream Julia MTK Tsit5 integration at abstol=1e-10, reltol=1e-10. 1e-6 covers Tsit5↔SciPy LSODA truncation over 3600 s plus float64 roundoff. Cly conservation runs at the same 1e-6 — it matches the upstream test tolerance (test/StratosphericChemistry_test.jl:289). Several anchors test small-fractional deltas near the initial reservoir mass (HCl, ClONO2 changing by 0.1-1% over short windows) — these use looser per-assertion abs floors derived from the variable magnitude (~1e15 m^-3 × 1e-6 = 1e9 abs floor).\n\nDomain validity: this is a stratospheric component. Defaults match the upstream component (T = 227 K and M = 3.1e23 m^-3 are ~30 km conditions; CH4 = 1e19 m^-3, O3 = 3e18 m^-3 are typical stratospheric values). All bath species (O, O3, NO, NO2, OH, CH4) are parameters here because the upstream component treats them as such — this cycle is a sub-model that runs against externally-prescribed environmental conditions, not a self-contained chemistry box. Coupling with the larger StratosphericOzoneSystem (test/StratosphericChemistry_test.jl:94+) is what promotes these to dynamical species; that integration is out of scope for this single-component migration."
  },
  "tolerance": {
    "rel": 1e-06
  },
  "variables": {
    "T": {
      "type": "parameter",
      "units": "K",
      "default": 227.0,
      "description": "Temperature. Default 227 K matches the upstream component and is the canonical 30 km stratospheric value (Seinfeld & Pandis Table 5.1)."
    },
    "j_ClONO2": {
      "type": "parameter",
      "units": "s^-1",
      "default": 0.0001,
      "description": "ClONO2 photolysis rate (ClONO2 + hν → Cl + NO3)."
    },
    "CH4": {
      "type": "parameter",
      "units": "m^-3",
      "default": 1e+19,
      "description": "Methane number density (1e13 molec/cm^3 × 1e6 → 1e19 m^-3). Drives the Cl + CH4 → HCl reservoir-formation channel."
    },
    "M": {
      "type": "parameter",
      "units": "m^-3",
      "default": 3.1e+23,
      "description": "Air number density at 30 km (3.1e17 molec/cm^3 × 1e6 → 3.1e23 m^-3). Third body for the ClO + NO2 + M → ClONO2 termolecular channel."
    },
    "O": {
      "type": "parameter",
      "units": "m^-3",
      "default": 10000000000000.0,
      "description": "Atomic oxygen number density (1e7 molec/cm^3 × 1e6 → 1e13 m^-3). Drives the ClO + O → Cl + O2 catalytic-cycle closing step."
    },
    "O3": {
      "type": "parameter",
      "units": "m^-3",
      "default": 3e+18,
      "description": "Ozone number density (3e12 molec/cm^3 × 1e6 → 3e18 m^-3). Drives the Cl + O3 → ClO + O2 catalytic-cycle initiating step."
    },
    "NO": {
      "type": "parameter",
      "units": "m^-3",
      "default": 1000000000000000.0,
      "description": "NO number density (1e9 molec/cm^3 × 1e6 → 1e15 m^-3). Drives the ClO + NO → Cl + NO2 alternative recycling channel."
    },
    "NO2": {
      "type": "parameter",
      "units": "m^-3",
      "default": 1000000000000000.0,
      "description": "NO2 number density (1e9 molec/cm^3 × 1e6 → 1e15 m^-3). Reactant in the ClO + NO2 + M → ClONO2 reservoir-formation channel."
    },
    "OH": {
      "type": "parameter",
      "units": "m^-3",
      "default": 1000000000000.0,
      "description": "OH number density (1e6 molec/cm^3 × 1e6 → 1e12 m^-3). Drives the OH + HCl → Cl + H2O reservoir-release channel."
    },
    "k_Cl_O3_A": {
      "type": "parameter",
      "units": "m^3/s",
      "default": 2.3e-17,
      "description": "Arrhenius pre-factor for Cl + O3 → ClO + O2 (upstream constant: 2.3e-11 cm^3/molec/s × 1e-6 → 2.3e-17 m^3/s, Seinfeld & Pandis Table B.1, p. 162)."
    },
    "C_Cl_O3": {
      "type": "parameter",
      "units": "K",
      "default": -200.0,
      "description": "Activation temperature (C = -E_a/R) for Cl + O3 (upstream constant: -200 K, Seinfeld & Pandis p. 162)."
    },
    "k_ClO_O_A": {
      "type": "parameter",
      "units": "m^3/s",
      "default": 3e-17,
      "description": "Arrhenius pre-factor for ClO + O → Cl + O2 (upstream constant: 3.0e-11 cm^3/molec/s × 1e-6 → 3.0e-17 m^3/s, Seinfeld & Pandis Table B.1, p. 162)."
    },
    "C_ClO_O": {
      "type": "parameter",
      "units": "K",
      "default": 70.0,
      "description": "Activation temperature for ClO + O (upstream constant: 70 K, Seinfeld & Pandis p. 162). Positive C means the reaction speeds up at low T (catalytic cycle is more efficient in the cold stratosphere)."
    },
    "k_ClO_NO_A": {
      "type": "parameter",
      "units": "m^3/s",
      "default": 6.4e-18,
      "description": "Arrhenius pre-factor for ClO + NO → Cl + NO2 (upstream constant: 6.4e-12 cm^3/molec/s × 1e-6 → 6.4e-18 m^3/s, Seinfeld & Pandis Table B.1, p. 163)."
    },
    "C_ClO_NO": {
      "type": "parameter",
      "units": "K",
      "default": 290.0,
      "description": "Activation temperature for ClO + NO (upstream constant: 290 K)."
    },
    "k_Cl_CH4_A": {
      "type": "parameter",
      "units": "m^3/s",
      "default": 9.6e-18,
      "description": "Arrhenius pre-factor for Cl + CH4 → HCl + CH3 (upstream constant: 9.6e-12 cm^3/molec/s × 1e-6 → 9.6e-18 m^3/s, Seinfeld & Pandis Table B.1, p. 168)."
    },
    "C_Cl_CH4": {
      "type": "parameter",
      "units": "K",
      "default": -1360.0,
      "description": "Activation temperature for Cl + CH4 (upstream constant: -1360 K — strongly endothermic, slow in the cold stratosphere)."
    },
    "k_OH_HCl_A": {
      "type": "parameter",
      "units": "m^3/s",
      "default": 2.6e-18,
      "description": "Arrhenius pre-factor for OH + HCl → Cl + H2O (upstream constant: 2.6e-12 cm^3/molec/s × 1e-6 → 2.6e-18 m^3/s, Seinfeld & Pandis p. 168)."
    },
    "C_OH_HCl": {
      "type": "parameter",
      "units": "K",
      "default": -350.0,
      "description": "Activation temperature for OH + HCl (upstream constant: -350 K)."
    },
    "k_ClO_NO2_M_A": {
      "type": "parameter",
      "units": "m^6/s",
      "default": 1.8e-43,
      "description": "Pre-factor for the termolecular ClO + NO2 + M → ClONO2 reaction at T_ref = 300 K (upstream constant: 1.8e-31 cm^6/molec^2/s × 1e-12 → 1.8e-43 m^6/s, Seinfeld & Pandis p. 165). Rate is k = A · (T_ref/T)^3.4, not Arrhenius."
    },
    "T_ref_ClO": {
      "type": "parameter",
      "units": "K",
      "default": 300.0,
      "description": "Reference temperature for the ClO + NO2 + M rate law k = k_A · (T_ref/T)^3.4."
    },
    "Cl": {
      "type": "unknown",
      "units": "m^-3",
      "default": 10000000000.0,
      "description": "Cl atom number density (upstream default initial value 1e4 molec/cm^3 × 1e6 → 1e10 m^-3)."
    },
    "ClO": {
      "type": "unknown",
      "units": "m^-3",
      "default": 10000000000000.0,
      "description": "ClO number density (upstream default initial value 1e7 molec/cm^3 × 1e6 → 1e13 m^-3)."
    },
    "HCl": {
      "type": "unknown",
      "units": "m^-3",
      "default": 1000000000000000.0,
      "description": "HCl reservoir number density (upstream default initial value 1e9 molec/cm^3 × 1e6 → 1e15 m^-3)."
    },
    "ClONO2": {
      "type": "unknown",
      "units": "m^-3",
      "default": 1000000000000000.0,
      "description": "ClONO2 reservoir number density (upstream default initial value 1e9 molec/cm^3 × 1e6 → 1e15 m^-3)."
    },
    "ClOx": {
      "type": "unknown",
      "units": "m^-3",
      "description": "Active chlorine family ClOx = Cl + ClO (algebraic). Catalytically destroys O3 via the Cl + O3 / ClO + O cycle."
    },
    "Cly": {
      "type": "unknown",
      "units": "m^-3",
      "description": "Total inorganic chlorine Cly = Cl + ClO + HCl + ClONO2 (algebraic). Conserved by the four ODEs (D(Cly) ≡ 0)."
    }
  },
  "equations": [
    {
      "lhs": {
        "op": "D",
        "wrt": "t",
        "args": [
          "Cl"
        ]
      },
      "rhs": {
        "op": "+",
        "args": [
          {
            "op": "-",
            "args": [
              {
                "op": "*",
                "args": [
                  -1,
                  {
                    "op": "*",
                    "args": [
                      "k_Cl_O3_A",
                      {
                        "op": "exp",
                        "args": [
                          {
                            "op": "/",
                            "args": [
                              "C_Cl_O3",
                              "T"
                            ]
                          }
                        ]
                      }
                    ]
                  },
                  "Cl",
                  "O3"
                ]
              },
              {
                "op": "*",
                "args": [
                  {
                    "op": "*",
                    "args": [
                      "k_Cl_CH4_A",
                      {
                        "op": "exp",
                        "args": [
                          {
                            "op": "/",
                            "args": [
                              "C_Cl_CH4",
                              "T"
                            ]
                          }
                        ]
                      }
                    ]
                  },
                  "Cl",
                  "CH4"
                ]
              }
            ]
          },
          {
            "op": "*",
            "args": [
              {
                "op": "*",
                "args": [
                  "k_ClO_O_A",
                  {
                    "op": "exp",
                    "args": [
                      {
                        "op": "/",
                        "args": [
                          "C_ClO_O",
                          "T"
                        ]
                      }
                    ]
                  }
                ]
              },
              "ClO",
              "O"
            ]
          },
          {
            "op": "*",
            "args": [
              {
                "op": "*",
                "args": [
                  "k_ClO_NO_A",
                  {
                    "op": "exp",
                    "args": [
                      {
                        "op": "/",
                        "args": [
                          "C_ClO_NO",
                          "T"
                        ]
                      }
                    ]
                  }
                ]
              },
              "ClO",
              "NO"
            ]
          },
          {
            "op": "*",
            "args": [
              {
                "op": "*",
                "args": [
                  "k_OH_HCl_A",
                  {
                    "op": "exp",
                    "args": [
                      {
                        "op": "/",
                        "args": [
                          "C_OH_HCl",
                          "T"
                        ]
                      }
                    ]
                  }
                ]
              },
              "OH",
              "HCl"
            ]
          },
          {
            "op": "*",
            "args": [
              "j_ClONO2",
              "ClONO2"
            ]
          }
        ]
      }
    },
    {
      "lhs": {
        "op": "D",
        "wrt": "t",
        "args": [
          "ClO"
        ]
      },
      "rhs": {
        "op": "-",
        "args": [
          {
            "op": "*",
            "args": [
              {
                "op": "*",
                "args": [
                  "k_Cl_O3_A",
                  {
                    "op": "exp",
                    "args": [
                      {
                        "op": "/",
                        "args": [
                          "C_Cl_O3",
                          "T"
                        ]
                      }
                    ]
                  }
                ]
              },
              "Cl",
              "O3"
            ]
          },
          {
            "op": "+",
            "args": [
              {
                "op": "*",
                "args": [
                  {
                    "op": "*",
                    "args": [
                      "k_ClO_O_A",
                      {
                        "op": "exp",
                        "args": [
                          {
                            "op": "/",
                            "args": [
                              "C_ClO_O",
                              "T"
                            ]
                          }
                        ]
                      }
                    ]
                  },
                  "ClO",
                  "O"
                ]
              },
              {
                "op": "*",
                "args": [
                  {
                    "op": "*",
                    "args": [
                      "k_ClO_NO_A",
                      {
                        "op": "exp",
                        "args": [
                          {
                            "op": "/",
                            "args": [
                              "C_ClO_NO",
                              "T"
                            ]
                          }
                        ]
                      }
                    ]
                  },
                  "ClO",
                  "NO"
                ]
              },
              {
                "op": "*",
                "args": [
                  {
                    "op": "*",
                    "args": [
                      "k_ClO_NO2_M_A",
                      {
                        "op": "^",
                        "args": [
                          {
                            "op": "/",
                            "args": [
                              "T_ref_ClO",
                              "T"
                            ]
                          },
                          3.4
                        ]
                      }
                    ]
                  },
                  "ClO",
                  "NO2",
                  "M"
                ]
              }
            ]
          }
        ]
      }
    },
    {
      "lhs": {
        "op": "D",
        "wrt": "t",
        "args": [
          "HCl"
        ]
      },
      "rhs": {
        "op": "-",
        "args": [
          {
            "op": "*",
            "args": [
              {
                "op": "*",
                "args": [
                  "k_Cl_CH4_A",
                  {
                    "op": "exp",
                    "args": [
                      {
                        "op": "/",
                        "args": [
                          "C_Cl_CH4",
                          "T"
                        ]
                      }
                    ]
                  }
                ]
              },
              "Cl",
              "CH4"
            ]
          },
          {
            "op": "*",
            "args": [
              {
                "op": "*",
                "args": [
                  "k_OH_HCl_A",
                  {
                    "op": "exp",
                    "args": [
                      {
                        "op": "/",
                        "args": [
                          "C_OH_HCl",
                          "T"
                        ]
                      }
                    ]
                  }
                ]
              },
              "OH",
              "HCl"
            ]
          }
        ]
      }
    },
    {
      "lhs": {
        "op": "D",
        "wrt": "t",
        "args": [
          "ClONO2"
        ]
      },
      "rhs": {
        "op": "-",
        "args": [
          {
            "op": "*",
            "args": [
              {
                "op": "*",
                "args": [
                  "k_ClO_NO2_M_A",
                  {
                    "op": "^",
                    "args": [
                      {
                        "op": "/",
                        "args": [
                          "T_ref_ClO",
                          "T"
                        ]
                      },
                      3.4
                    ]
                  }
                ]
              },
              "ClO",
              "NO2",
              "M"
            ]
          },
          {
            "op": "*",
            "args": [
              "j_ClONO2",
              "ClONO2"
            ]
          }
        ]
      }
    },
    {
      "lhs": "ClOx",
      "rhs": {
        "op": "+",
        "args": [
          "Cl",
          "ClO"
        ]
      }
    },
    {
      "lhs": "Cly",
      "rhs": {
        "op": "+",
        "args": [
          "Cl",
          "ClO",
          "HCl",
          "ClONO2"
        ]
      }
    }
  ],
  "tests": [
    {
      "id": "default_30km_short_window",
      "description": "Reference trajectory at upstream default conditions (T = 227 K, M = 3.1e23 m^-3 — 30 km, defaults for all bath species, initial Cl = 1e10, ClO = 1e13, HCl = 1e15, ClONO2 = 1e15). Samples Cl, ClO, HCl, ClONO2, and the algebraic family sums ClOx and Cly at t = 0, 1, 60, 600 s. Pinned from upstream Julia MTK Tsit5 integration at abstol=1e-10, reltol=1e-10. Exercises all four ODE channels (Cl + O3, ClO + O, ClO + NO, Cl + CH4, OH + HCl, ClO + NO2 + M, j_ClONO2) and both algebraic family sums simultaneously.",
      "time_span": {
        "start": 0.0,
        "end": 600.0
      },
      "assertions": [
        {
          "variable": "Cl",
          "time": 0.0,
          "expected": 10000000000.0
        },
        {
          "variable": "ClO",
          "time": 0.0,
          "expected": 10000000000000.0
        },
        {
          "variable": "HCl",
          "time": 0.0,
          "expected": 1000000000000000.0
        },
        {
          "variable": "ClONO2",
          "time": 0.0,
          "expected": 1000000000000000.0
        },
        {
          "variable": "ClOx",
          "time": 0.0,
          "expected": 10010000000000.0
        },
        {
          "variable": "Cly",
          "time": 0.0,
          "expected": 2010010000000000.0
        },
        {
          "variable": "Cl",
          "time": 1.0,
          "expected": 11667854808.897636
        },
        {
          "variable": "ClO",
          "time": 1.0,
          "expected": 10094658379034.93
        },
        {
          "variable": "HCl",
          "time": 1.0,
          "expected": 1000002222141430.2,
          "tolerance": {
            "abs": 1000000000.0
          }
        },
        {
          "variable": "ClONO2",
          "time": 1.0,
          "expected": 999901451624726.2,
          "tolerance": {
            "abs": 1000000000.0
          }
        },
        {
          "variable": "ClOx",
          "time": 1.0,
          "expected": 10106326233843.828
        },
        {
          "variable": "Cl",
          "time": 60.0,
          "expected": 16190275896.757105
        },
        {
          "variable": "ClO",
          "time": 60.0,
          "expected": 15698213820352.043
        },
        {
          "variable": "ClOx",
          "time": 60.0,
          "expected": 15714404096248.8
        },
        {
          "variable": "Cl",
          "time": 600.0,
          "expected": 52499282405.076584
        },
        {
          "variable": "ClO",
          "time": 600.0,
          "expected": 60699774240375.87
        },
        {
          "variable": "HCl",
          "time": 600.0,
          "expected": 1004412905738617.2
        },
        {
          "variable": "ClONO2",
          "time": 600.0,
          "expected": 944844820738602.4
        },
        {
          "variable": "ClOx",
          "time": 600.0,
          "expected": 60752273522780.945
        }
      ]
    },
    {
      "id": "default_30km_long_window_one_hour",
      "description": "Same upstream-default conditions extended to t = 3600 s (1 hour) — the exact window of the upstream `ClOx Cycle Integration` test (test/StratosphericChemistry_test.jl:182-202). At this point HCl has grown ~8% (~1.08e15) and ClONO2 has dropped ~25% (~7.5e14), as ClO + NO2 + M / ClONO2 + hν has not yet reached steady state and the Cl + CH4 / OH + HCl channel slowly transfers Cl into HCl. Exercises long-window numerical agreement and verifies positivity-preservation (all species ≥ 0) as the upstream test asserts.",
      "time_span": {
        "start": 0.0,
        "end": 3600.0
      },
      "assertions": [
        {
          "variable": "Cl",
          "time": 3600.0,
          "expected": 145917563476.57654
        },
        {
          "variable": "ClO",
          "time": 3600.0,
          "expected": 176769411036707.2
        },
        {
          "variable": "HCl",
          "time": 3600.0,
          "expected": 1082448634324647.6
        },
        {
          "variable": "ClONO2",
          "time": 3600.0,
          "expected": 750646037075181.4
        },
        {
          "variable": "ClOx",
          "time": 3600.0,
          "expected": 176915328600183.75
        }
      ]
    },
    {
      "id": "cly_conservation_short_window",
      "description": "Reproduces the upstream `Cly Conservation (ClOx Cycle)` test (test/StratosphericChemistry_test.jl:266-290): integrating 1 s under defaults, total inorganic chlorine Cly = Cl + ClO + HCl + ClONO2 must remain at its initial value 2.01001e15 m^-3 to rtol = 1e-6. Analytically D(Cly) = D(Cl) + D(ClO) + D(HCl) + D(ClONO2) ≡ 0, so any deviation is integrator roundoff. Samples Cly at three points spanning the integration window.",
      "time_span": {
        "start": 0.0,
        "end": 1.0
      },
      "assertions": [
        {
          "variable": "Cly",
          "time": 0.0,
          "expected": 2010010000000000.0
        },
        {
          "variable": "Cly",
          "time": 0.1,
          "expected": 2010010000000000.5
        },
        {
          "variable": "Cly",
          "time": 0.5,
          "expected": 2010010000000000.5
        },
        {
          "variable": "Cly",
          "time": 1.0,
          "expected": 2010010000000000.5
        }
      ]
    },
    {
      "id": "warm_temperature_40km",
      "description": "Reference trajectory at T = 251 K (40 km conditions, Seinfeld & Pandis Table 5.1) with all other parameters at defaults. Warmer T accelerates the Arrhenius positive-C channels (ClO + O, ClO + NO, OH + HCl) and slows the negative-C channels (Cl + O3, Cl + CH4) — net effect is faster ClOx cycling (ClO at 1 hour ≈ 1.63e14, vs ~1.77e14 at 30 km). Exercises the temperature-dependent rate-law branch at a textbook-relevant altitude. Reference values pinned from upstream Tsit5 integration.",
      "time_span": {
        "start": 0.0,
        "end": 3600.0
      },
      "parameter_overrides": {
        "T": 251.0
      },
      "assertions": [
        {
          "variable": "Cl",
          "time": 600.0,
          "expected": 42172605375.89072
        },
        {
          "variable": "ClO",
          "time": 600.0,
          "expected": 59592773138181.42
        },
        {
          "variable": "HCl",
          "time": 600.0,
          "expected": 1006449594334760.8
        },
        {
          "variable": "ClONO2",
          "time": 600.0,
          "expected": 943925459921681.9
        },
        {
          "variable": "Cl",
          "time": 3600.0,
          "expected": 109484925766.25302
        },
        {
          "variable": "ClO",
          "time": 3600.0,
          "expected": 163039344052707.62
        },
        {
          "variable": "HCl",
          "time": 3600.0,
          "expected": 1113523856447711.2
        },
        {
          "variable": "ClONO2",
          "time": 3600.0,
          "expected": 733337314573806.8
        }
      ]
    },
    {
      "id": "no_methane_channel",
      "description": "Methane-free scenario (CH4 = 0). Eliminates the Cl + CH4 → HCl reservoir-formation channel, so HCl can only decrease (OH + HCl → Cl is the only HCl term). After 1 hour HCl has dropped ~0.2% (vs growing ~8% at default CH4) because the only HCl source is the externally-prescribed OH + HCl reaction. Exercises the parameter-sweep behavior of the CH4 channel; reference values pinned from upstream Tsit5 integration.",
      "time_span": {
        "start": 0.0,
        "end": 3600.0
      },
      "parameter_overrides": {
        "CH4": 0.0
      },
      "assertions": [
        {
          "variable": "Cl",
          "time": 60.0,
          "expected": 16488836255.480213
        },
        {
          "variable": "ClO",
          "time": 60.0,
          "expected": 15897307817018.953
        },
        {
          "variable": "HCl",
          "time": 600.0,
          "expected": 999666239397679.0,
          "tolerance": {
            "abs": 10000000000.0
          }
        },
        {
          "variable": "HCl",
          "time": 3600.0,
          "expected": 997999106584768.9,
          "tolerance": {
            "abs": 10000000000.0
          }
        },
        {
          "variable": "ClO",
          "time": 3600.0,
          "expected": 247575679957642.84
        }
      ]
    },
    {
      "id": "no_no2_channel",
      "description": "NO2-free scenario (NO2 = 0). Eliminates the ClO + NO2 + M → ClONO2 reservoir-formation channel, so ClONO2 can only decrease (ClONO2 + hν → Cl is the only ClONO2 term). After 1 hour ClONO2 has dropped ~30% (vs ~25% at default NO2) because the photolysis loss is no longer balanced by formation. Exercises the parameter-sweep behavior of the termolecular ClO + NO2 + M channel; reference values pinned from upstream Tsit5 integration.",
      "time_span": {
        "start": 0.0,
        "end": 3600.0
      },
      "parameter_overrides": {
        "NO2": 0.0
      },
      "assertions": [
        {
          "variable": "Cl",
          "time": 60.0,
          "expected": 16279100182.742704
        },
        {
          "variable": "ClO",
          "time": 60.0,
          "expected": 15808340135467.223
        },
        {
          "variable": "ClONO2",
          "time": 600.0,
          "expected": 941764533584252.1
        },
        {
          "variable": "ClONO2",
          "time": 3600.0,
          "expected": 697676326071035.1
        },
        {
          "variable": "ClO",
          "time": 3600.0,
          "expected": 217428446195968.0
        }
      ]
    }
  ],
  "analyses": [
    {
      "id": "clox_cycle_default_one_hour",
      "description": "Default 30 km stratospheric run (T = 227 K, M = 3.1e23 m^-3, upstream initial conditions) over 1 hour. Surfaces the canonical ClOx-cycle behavior: ClO grows by ~18x as Cl + O3 drives the catalytic cycle, while HCl slowly accumulates and ClONO2 partially photolyzes. Reproduces the upstream `ClOx Cycle Integration` reference run (test/StratosphericChemistry_test.jl:182).",
      "initial_state": {
        "Cl": 10000000000.0,
        "ClO": 10000000000000.0,
        "HCl": 1000000000000000.0,
        "ClONO2": 1000000000000000.0
      },
      "time_span": {
        "start": 0.0,
        "end": 3600.0
      },
      "plots": [
        {
          "id": "active_clox_vs_time",
          "type": "line",
          "description": "Active ClOx species (Cl, ClO) vs time at 30 km defaults. Cl tracks ClO via the quasi-steady Cl/ClO ratio set by Eq. 5.30; both grow as Cl + O3 outpaces the reservoir-formation channels in the first hour.",
          "x": {
            "variable": "t",
            "label": "time (s)"
          },
          "y": {
            "variable": "ClO",
            "label": "ClO (m^-3)"
          }
        },
        {
          "id": "reservoir_species_vs_time",
          "type": "line",
          "description": "Reservoir species (HCl, ClONO2) vs time at 30 km defaults. HCl grows slowly via Cl + CH4, while ClONO2 partially photolyzes — the two reservoirs equilibrate on different timescales because the formation/loss rate constants differ.",
          "x": {
            "variable": "t",
            "label": "time (s)"
          },
          "y": {
            "variable": "ClONO2",
            "label": "ClONO2 (m^-3)"
          }
        },
        {
          "id": "cly_conservation_vs_time",
          "type": "line",
          "description": "Total inorganic chlorine Cly = Cl + ClO + HCl + ClONO2 vs time at 30 km defaults. Should remain constant at the initial value 2.01001e15 m^-3 — the upstream Cly Conservation test reference plot.",
          "x": {
            "variable": "t",
            "label": "time (s)"
          },
          "y": {
            "variable": "Cly",
            "label": "Cly (m^-3)"
          }
        }
      ]
    },
    {
      "id": "clox_cycle_temperature_sweep",
      "description": "Sweep T over the stratospheric range [200, 270] K at otherwise-default conditions. Surfaces the temperature dependence of the ClOx cycle: ClO at t = 3600 s rises with T (the positive-C Arrhenius channels — ClO + O, ClO + NO, OH + HCl — speed up faster than the negative-C channels — Cl + O3, Cl + CH4 — slow down). The termolecular ClO + NO2 + M → ClONO2 also slows at higher T (k ∝ (T_ref/T)^3.4), shifting the partition away from the ClONO2 reservoir.",
      "initial_state": {
        "Cl": 10000000000.0,
        "ClO": 10000000000000.0,
        "HCl": 1000000000000000.0,
        "ClONO2": 1000000000000000.0
      },
      "time_span": {
        "start": 0.0,
        "end": 3600.0
      },
      "parameter_sweep": {
        "type": "cartesian",
        "dimensions": [
          {
            "parameter": "T",
            "range": {
              "start": 200.0,
              "stop": 270.0,
              "count": 8,
              "scale": "linear"
            }
          }
        ]
      },
      "plots": [
        {
          "id": "ClO_final_vs_T",
          "type": "line",
          "description": "Final ClO at t = 3600 s vs temperature: shows the temperature-dependent saturation of the ClOx cycle as the relative weight of Arrhenius positive-C / negative-C / termolecular channels shifts.",
          "x": {
            "variable": "T",
            "label": "T (K)"
          },
          "y": {
            "variable": "ClO",
            "label": "ClO at t=3600 s (m^-3)"
          }
        }
      ]
    }
  ]
}