Monday, 14 January 2002: 4:45 PM
Transport of Aerosol Particles by Deep Convective Process and Its Contribution to the Formation of Junge Layer
The relative maximum of the global vertical aerosol concentration profile in the lower stratosphere is commonly referred to as the Junge aerosol layer, or simply the Junge layer. It is of great importance to study the formation of this layer and to monitor its changes because of the possible impacts of these stratospheric aerosols to global climate. At present, the formation mechanism of the Junge layer is not well understood. Current theories of Junge layer formation include the injection of sulfate particles by volcanic eruptions, turbulent diffusion of tropospheric sulfates, natural (biogenic) emissions of carbonyl sulfide, and other processes. This paper will demonstrate the feasibility of vertical transport of materials (both gases and particulates) from the troposphere to the stratosphere by the deep convective process and the potential of this process as a formation mechanism of the Junge layer. We will use a cloud dynamical model coupled with detailed microphysics package to simulate the transport of materials from the troposphere to the stratosphere during deep convective process. We will show simulation results for both inert tracer transport and the transport of sulfur species, the latter including chemical reactions in clouds that transform sulfur dioxide to sulfate particles. We will present estimates of the transport rates by typical deep convective storms in low and midlatitudes. Tangible evidence of such transport mechanism, mainly by satellite observations, will also be shown. Finally, the possible contribution of this deep convective transport to the Junge layer formation will be assessed.