Stratospheric Inorganic Bromine Loading Inferred from CONTRAST BrO and Organic Bromine Observations

The CONvective TRansport of Active Species in the Tropics (CONTRAST) and Airborne Tropical TRopopause EXperiment (ATTREX) aircraft campaigns sampled the tropical Western Pacific in the winter of 2014. In this region, strong convection provides an efficient pathway to transport very short lived (VSL) biogenic bromocarbons and their degradation products from the marine boundary layer to the stratosphere, where they contribute to ozone depletion. A stratospheric tracer-tracer relation will be developed based on CONTRAST and ATTREX whole air sampler observations of CFC-11, a commonly measured stratospheric tracer, and bromocarbons. This relation will be used to calculate the release of inorganic bromine both from VSL source gas injection and from long-lived bromocarbons as a function of CFC-11. Additionally, a photochemical box model will be used to infer inorganic bromine loading using CONTRAST BrO observations taken in the lower stratosphere using CIMS and DOAS instruments. The inferred inorganic bromine loading will be combined with the tracer-tracer relation to provide an estimate of VSL product gas injection. This work will provide an observations-based method for calculating stratospheric inorganic bromine loading from CFC-11 to be used in future modelling studies.