Modelling multi-phase halogen chemistry in the remote marine boundary layer: investigation of the influence of aerosol size resolution on predicted gas- and condensed-phase chemistry

摘要

A coupled box model of photochemistry and aerosol microphysics which explicitlyaccounts for size-dependent chemical properties of the condensed-phase has beendeveloped to simulate the multi-phase chemistry of chlorine, bromine and iodine inthe marine boundary layer (MBL). The model contains separate seasalt andnon-seasalt modes, each of which may be composed of 1–16 size-bins. Bycomparison of gaseous and aerosol compositions predicted using differentsize-resolutions with both fixed and size-dependent aerosol turnover rates, itwas found that, for halogen-activation processes, the physical propertyinitialisation of the aerosol-mode has a significant influence on gas-phasechemistry. Failure to adequately represent the appropriate physical propertiescan lead to substantial errors in gas-phase chemistry. The size-resolution ofcondensed-phase composition has a less significant influence on gas-phase chemistry.