PHYSICAL ANALOGS AND PERFORMANCE OF A BOX MODEL FOR COMPOLITION AND GROWTH OF H_2SO_4/H_2O AND HNO_3/H_2SO_4/H_2O AEROSOL IN THE STRATOSPHERE

摘要

A physical box model simulating the aerosol particle evolution along air mass trajectouies is developed to provide a tool for interpreting the socal observations of stratospheric aerosols (i.e.,polar stratospheric clouds).The model calculates the composition and the size distributions of H_2SO_4/H_2O and HNO_3/H_2SO_4/H_2O liquid droplets.The parameterization of the physical pro-cesses affecting the dynamics of HNO_3and H_2SO_4 solid hydrates and ice particle size distrbutions is also included,but not used.This work is restricted to some speculations about the liquid to solid transition,acoording to existing theouies.The evolution of liquid particles is simulated taking into account nucleation,diffusive condensation/evaporation and coagulation.This paper reports the physical and numerical details of the model,which are discussed within the framework of the current understanding of the stratospheric aerosol physics.Performance and limitations of the liquid strato-spheric aerosols consisting of HNO_3/H_2SO_4/H_2O are calculated in the cases of air mass thermal histories with different cooling rates and with rapid temperature fluctuations.direct C 1999 Elsevier Science Ltd.All rights reserved