9424433 Garstang This award will continue the "Characterization of Aerosols over Southern Africa (C-CASA)" which is directed solely at the analysis of the field generated data gathered under CASA and the larger umbrella experiments of SAFARI-TRACE-A conducted in southern Africa, the southern tropical Atlantic and Brazil in September- October 1992. The objective of C-CASA is to determine the characteristics of aerosols originating over the savannas of southern Africa. The overall objectives are now refined and expended on given the knowledge of what was achieved in the field. Chemical and isotopic composition of surface and airborne samples will be completed. Aerosol mass as well as elemental concentrations over continental source regions and in downstream regions of transports will be determined. Isotopes of nitrogen and oxygen together with changes in concentrations of elements in the aerosol samples will be combined with kinematic (trajectory) and thermodynamic (atmospheric conservative properties and stability) to determine 4-D (x,y,z,t) transports. Transports will be traced to the source locations in a horizontal framework ranging from regional to continental scales and in a lagrangian coordinate system following the trajectory as a function of height.
