Stratospheric

Stratospheric bromine catalytic ozone-destruction cycle (BrOx). Three ODEs (Br, BrO, HOBr) and two algebraic family identities (BrOx = Br + BrO; Bry = Br + BrO + HOBr). Reactions: Br + O3 → BrO + O2 (Arrhenius); BrO + O → Br + O2; BrO + ClO → Br + Cl + O2 (constant rate); BrO + HO2 → HOBr + O2; HOBr + hν → OH + Br (photolysis). Unlike chlorine, bromine has no stable HBr reservoir because Br + CH4 is endothermic (Seinfeld & Pandis Page 169). Bromine is approximately 50× more effective than chlorine in destroying ozone on an atom-for-atom basis. Migrated from GasChem.jl@8c12c048 src/StratosphericChemistry.jl:390 (`BrOxCycle` @component). Rate coefficients converted CGS → SI: cm³/molec/s × 1e-6 → m³/s.

Stratospheric Chapman mechanism for ozone production and destruction (Seinfeld & Pandis 2006 Ch. 5, §5.2, Eqs. 5.1-5.17). Two-state ODE on atomic oxygen O and ozone O3 driven by the four canonical Chapman reactions: O2 photolysis (j_O2), three-body recombination O + O2 + M → O3 + M (k2 with power-law T-dependence (T_ref/T)^2.4), O3 photolysis (j_O3), and the O + O3 → 2 O2 odd-oxygen sink (k4 with Arrhenius temperature dependence). Odd oxygen Ox = O + O3 is *not* exactly conserved — the Chapman cycle has a net Ox source (2·j_O2·O2·M from O2 photolysis) balanced against an Ox sink (2·k4·O·O3 from the O+O3 reaction) — but on short timescales (≲ 10 s under default mid-stratosphere conditions) the net change is small (~4e-5 relative drift) and the upstream test treats it as quasi-conserved at rtol=1e-4. Migrated from GasChem.jl@8c12c048 src/StratosphericChemistry.jl:51 (`ChapmanMechanism` @component). Rate coefficients carry SI units throughout, converted from Seinfeld & Pandis CGS values via cm^6/molec^2/s × 1e-12 → m^6/s for the 3-body k2 and cm^3/molec/s × 1e-6 → m^3/s for the bimolecular k4.

Stratospheric ClOx catalytic ozone destruction cycle (Seinfeld & Pandis 2006, Ch. 5 §5.5.1). Migrated from GasChem.jl@8c12c048 src/StratosphericChemistry.jl:272 (`ClOxCycle` @component). Implements 4 ODEs (Cl, ClO, HCl, ClONO2) coupled to 2 algebraic family sums (ClOx = Cl + ClO, Cly = Cl + ClO + HCl + ClONO2). Rate coefficients are Arrhenius (k = A·exp(C/T)) for the five binary reactions and a (T_ref/T)^3.4 form for the termolecular ClO + NO2 + M → ClONO2 channel. All upstream `@constants` are encoded as parameters with their literal SI defaults; physical-condition `@parameters` (T, M, photolysis rates, fixed-bath species O, O3, NO, NO2, OH, CH4) are also parameters so the cycle can be exercised at different atmospheric conditions.

Stratospheric HOx catalytic ozone destruction cycle (Seinfeld & Pandis 2006 Ch. 5, §5.4, Eqs. 5.23-5.28). Two-state ODE on the radicals OH and HO2 driven by reactions with O3, atomic O, and NO; HOx = OH + HO2 is exactly conserved by construction (D(OH) + D(HO2) ≡ 0). Migrated from GasChem.jl@8c12c048 src/StratosphericChemistry.jl:187 (`HOxCycle` @component). All rate coefficients are temperature-dependent Arrhenius forms k_X = k_X_A · exp(C_X / T) with the Seinfeld & Pandis bimolecular CGS pre-factors converted to SI via the cm³/molec/s × 1e-6 → m³/s factor; SI rates and SI number-density concentrations (m^-3) are preserved verbatim from upstream.

Stratospheric NOx catalytic ozone destruction cycle (Seinfeld & Pandis 2006 Ch. 5 §5.3.2, Eqs. 5.20-5.22). Two-state ODE on the NOx radicals NO and NO2 driven by reactions with O3 and atomic O, plus daytime NO2 photolysis; NOx = NO + NO2 is exactly conserved by construction (D(NO) + D(NO2) ≡ 0). Migrated from GasChem.jl@8c12c048 src/StratosphericChemistry.jl:118 (`NOxCycle` @component). Rate coefficients are temperature-dependent Arrhenius forms k_X = k_X_A · exp(C_X / T) with the Seinfeld & Pandis bimolecular CGS pre-factors converted to SI via the cm³/molec/s × 1e-6 → m³/s factor; SI rates and SI number-density concentrations (m^-3) preserved verbatim from upstream.

Comprehensive stratospheric ozone chemistry (Seinfeld & Pandis 2006, Chapter 5) — a monolithic 15-state ODE plus 5 algebraic family sums combining the Chapman mechanism, O(1D) photochemistry, the N2O NOx source, and the NOx / HOx / ClOx / BrOx catalytic ozone-destruction cycles. Migrated from GasChem.jl@8c12c048 src/StratosphericChemistry.jl:497. SI units throughout.