On the contribution of chemical oscillations to ozone depletion events in the polar spring

Abstract

Abstract. This paper presents a numerical study of the oscillations (or recurrences) of tropospheric ozone depletion events (ODEs) using the further-developed one-dimensional KInetic aNALysis of reaction mechanics with Transport (KINAL-T) chemistry transport model. Reactive bromine is the major contributor to the occurrence of ODEs. After the termination of an ODE, the reactive bromine in the air is deposited onto aerosols or on the snow surface, and the ozone may regenerate via NOx-catalyzed photochemistry or by turbulent transport from the free troposphere into the boundary layer. The replenished ozone then is available for the next cycle of autocatalytic bromine release (bromine explosion) leading to another ODE. The oscillation periods are found to be as short as 5 d for the purely chemically NOx-driven oscillation and 30 d for a diffusion-driven oscillation. An important requirement for oscillation of ODEs to occur is found to be a sufficiently strong inversion layer. In a parameter study, the dependence of the oscillation period on the nitrogen oxides' concentration, the inversion layer strength, the ambient temperature, the aerosol density, and the solar radiation is investigated. Parameters controlling the oscillation of ODEs are discussed.

Time-dependent 3D simulations of tropospheric ozone depletion events in the Arctic spring using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem)

“…ERA-Interim (Dee et al, 2011) is used to generate both the initial and boundary meteorological and sea ice cover data. ERA-Interim was found to perform well in polar regions in various studies (e.g., Bracegirdle and Marshall, 2012;Bromwich et al, 2016) and was successfully used in various modeling studies in polar regions (e.g., Hines et al, 2015;Cai et al, 2018), which is why it was chosen in the present study. Nudging of temperature, horizontal wind speed, humidity, and surface fields to ERA-Interim data ensures the validity of the simulation meteorology over the simulated 3-month period.…”

The Role of Snow in Controlling Halogen Chemistry and Boundary Layer Oxidation During Arctic Spring: A 1D Modeling Case Study

“…(2016) and used in Herrmann et al. (2019). We calculate these values as measurement data of eddy diffusion coefficients during this period were sparse.…”

“…Figure 4 shows that we are able to obtain very good agreement of both the surface and vertical temperature profiles in WRF compared to the observations. The eddy diffusion coefficients (K z ) in the model are calculated following the parameterization described in Cao et al (2016) and used in Herrmann et al (2019). We calculate these values as measurement data of eddy diffusion coefficients during this period were sparse.…”

3D simulations of tropospheric ozone depletion events using WRF-Chem

“…In the present study, the MOZART-MOSAIC mechanism based on MOZART-4 (Model for Ozone and Related chemical Tracers) gas-phase chemistry (Emmons et al, 2010a) is used which includes 85 gas-phase species, 237 gas-phase reactions, 49 photolysis reactions. Additional 18 gas-phase species, 73 gas-phase reactions, and 13 photolysis reactions (Herrmann et al, 2019) account for the bromine and chlorine chemistry (termed "full chemistry", see Tab. 2).…”