Modeling the formation of polar stratospheric clouds with allowance for kinetic and heterogeneous processes

Abstract

A new mathematical model of global transport of multicomponent gaseous admixtures and aero sols in the atmosphere and the formation of polar stratospheric clouds (PSC) in both hemispheres has been constructed. Two types of PSCs are considered: type Ia, nitric acid trihydrate (NAT), and type Ib, super cooled ternary solutions of H 2 SO 4 /HNO 3 /H 2 O (STS). New equations are used to describe the variation in gas and condensed phase components on the basis of their thermodynamic properties. The formation of PSCs is coupled with sulfate aerosols generated in the upper troposphere and lower stratosphere, and with chemical and kinetic transformation processes (photochemistry, nucleation, condensation/evaporation, and coagulation). Using this coupled model, numerical experiments were performed to reproduce the spatial and temporal variability of PSCs in winter in both hemispheres. First, the formation of primary sulfate aerosols in the atmosphere is considered and then these aerosols are incorporated to the PSC model. The results of the numerical experiments are analyzed.