Formation of polar stratospheric clouds simulated in a two dimensional model of the atmosphere

Abstract

A microphysics code has been implemented in a two dimensional model of the atmosphere to study formation of polar stratospheric clouds containing HCl or HNO3. The model range is from pole to pole in latitude and from the ground to about 20 km in altitude. Resolution in latitude is 10 deg and about 0.8 km in altitude. This is an Eulerian model with prescribed eddy diffusion coefficients and the circulation obtained from observations. The chemistry of the model follows the family approach for NO(x), Cl(x) and HO(x) while the ozone is fixed and changed seasonally. The aerosol code is based on an assigned population of condensation, coagulation and sedimentation. Aerosol growth is simulated in nine different size bins ranging between 0.01u and 2.56u. The model has been built to study aerosol layers formation in the upper troposphere and lower stratosphere and has been validated for sulfate aerosol resulting from a rather complex sulfur chemistry