| Two comprehensive field campaigns on desert dust were conducted in 2006 and 2008
in the framework of the Saharan Mineral Dust Experiment (SAMUM) project.
SAMUM–1 took place in southern Morocco close to the Saharan desert at pure
dust conditions in the summer of 2006, whereas SAMUM–2 was conducted in
Cape Verde in the outflow region of desert dust and biomass burning smoke from
western Africa in the winter of 2008. The relationship between chemical composition,
shape morphology, size distribution, and optical effects of the dust particles was
investigated. The impact of Saharan dust on radiative transfer and the feedback of radiative
effects upon dust emission and aerosol transport were studied. State-of-the-art field
observations (ground–based and airborne in situ measurements, multiwavelength
polarization Raman and HSRL lidars, Sun photometers with 1640Â nm channels,
radiometers) and modelling results were compared within a variety of dust closure
experiments with a strong focus on vertical profiling of desert dust properties. This
presentation summarizes the highlights and main findings of the SAMUM observations
and modelling efforts, but also presents a list of remaining problems and unsolved
questions.
Another tropical dust experiment is planned for the summer of 2013 and the
spring of 2014, the respective proposal was submitted end of 2011 (national funding,
DFG). The Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction
Experiment (SALTRACE) is proposed to take place at Barbados. The research focus is
on (a) the transport and transformation (aging, cloud processing, contamination)
of African mineral dust and biomass burning smoke in the far field regime (i.e.,
towards the Americas), about 6000-7000Â km west of the main desert dust sources
and (b) the impact of aged dust on cloud formation, especially the evolution of
deep convection. The motivation, design, and plans of SALTRACE will be briefly
outlined. |