Numerical simulation of tropospheric ozone depletion in the polar spring

This study addresses the modeling of the tropospheric ozone depletion event in polar spring where the aim is an improved understanding of the underlying physical and chemical processes. For this purpose, a model is developed and implemented into the open source software Open source Field Operations And Manipulations (OpenFOAM). A detailed chemical reaction mechanism is analyzed with the software package KInetic aNALysis of reaction mechanics (KINAL), and a skeletal mechanism is derived for use in the three-dimensional simulations. The 3D compressible Navier–Stokes equations are solved to predict the effect of turbulent mixing, advection of the fluid, and chemical reactions. Large eddy simulation accounts for the turbulence, and the Smagorinsky model is employed as sub-grid model. The temporal and spatial distributions of the chemical species are captured. The mixing ratio of ozone in the troposphere drops to a value near zero within several days including an “induction stage” and a “depletion stage,” which confirms previous findings. Moreover, the vertical turbulent mixing of air parcels occurs below the height of the polar boundary layer, leading to a nonuniform vertical distribution of the chemical species concentrations. Both the wind speed and the boundary layer stability may affect the boundary layer height, thus influencing the ozone depletion rate.