Intercomparison Between Surrogate, Explicit, and Full Treatments of VSL Bromine Chemistry Within the CAM-Chem Chemistry-Climate Model

FERNANDEZ, RAFAEL P.; BARRERA, JAVIER A.; LÓPEZ-NOREÑA, ANA ISABEL; KINNISON, DOUGLAS E.; NICELY, JULIE; SALAWITCH, ROSS J.; WALES, PAMELA A.; TOSELLI, BEATRIZ M.; TILMES, SIMONE; LAMARQUE, JEAN-FRANÇOIS; CUEVAS, CARLOS A.; SAIZ-LOPEZ, ALFONSO

GEOPHYSICAL RESEARCH LETTERS

AMER GEOPHYSICAL UNION

Año: 2021 vol. 48

0094-8276

any Chemistry-Climate Models (CCMs) include a simplified treatment of brominated very short-lived (VSLBr) species by assuming CH3Br as a surrogate for VSLBr. However, neglecting a comprehensive treatment of VSLBr in CCMs may yield an unrealistic representation of the associated impacts. Here, we use the Community Atmospheric Model with Chemistry (CAM-Chem) CCM to quantify the tropospheric and stratospheric changes between various VSLBr chemical approaches with increasing degrees of complexity (i.e., surrogate, explicit, and full). Our CAM-Chem results highlight the improved accuracy achieved by considering a detailed treatment of VSLBr photochemistry, including sea-salt aerosol dehalogenation and heterogeneous recycling on ice-crystals. Differences between the full and surrogate schemes maximize in the lowermost stratosphere and midlatitude free troposphere, resulting in a latitudinally dependent reduction of ∼1?7 DU in total ozone column and a ∼5%?15% decrease of the OH/H