Modeling the Sources and Chemistry of Polar Tropospheric Halogens (Cl, Br, I) using the CAMChem Global ChemistryClimate Model

SAIZ-LOPEZ, ALFONSO

Journal of Advances in Modeling Earth Systems

Wiley-Blackwell

Año: 2019

1942-2466

urrent chemistry climate models do not include polar emissions and chemistry of halogens. This work presents the first implementation of an interactive polar module into the very short-lived (VSL) halogen version of the CAM-Chem model. The polar module includes photochemical release of molecular bromine, chlorine and interhalogens from the sea-ice surface, and brine diffusion of iodine biologically produced underneath porous sea-ice. It also includes heterogeneous recycling of inorganic halogen reservoirs deposited over fresh sea-ice surfaces and snow covered regions. The polar emission of chlorine, bromine and iodine reach approximately 32, 250 and 39 Gg yr −1 for Antarctica and 33, 270 and 4 Gg yr −1 for the Arctic, respectively, with a marked seasonal cycle mainly driven by sunlight and sea-ice coverage. Model results are validated against polar boundary layer measurements of ClO, BrO and IO, and satellite BrO and IO columns. This validation includes satellite observati