Introduction - Mineral Dust: A Key Player in the Earth System - page 3

Martinez-Garcia et al. 2011 ). It has been hypothesised that the Amazon rainforest
is fertilised significantly by Saharan dust (e.g. Bristow et al. 2010 ) and that the
fertilising effect on the ocean is potentially so large that it plays an important role in
global climate (Martin 1990 ).
In addition, dust plays an important role in different aspects of weather
and climate dynamics, the Earth's radiative budget, cloud microphysics and
atmospheric chemistry. The radiative heating of airborne dust modifies the
energetics of the atmosphere, including possible modifications of easterly waves
and tropical cyclone development over the Atlantic Ocean, downwind of the Sahara
Desert (Karyampudi and Carlson 1988 ; Karyampudi and Pierce 2002 ).
As stressed by both the fourth and recent fifth assessment of the International
Panel of Climate Change, the level of scientific understanding of the effects of
aerosols, both natural and anthropogenic, on climate is generally low (Forster
et al. 2007 ; Myhre et al. 2013 ). Considerable advances in the knowledge of dust
mobilisation, dispersal and deposition as well as impacts of atmospheric dust have
been made, but many open questions remain.

1.2 A Short History of Dust Research

Dust storms and atmospheric dust processes have attracted societal attention for
millennia. In ancient Korea, for example, dust events caused concern because
they were considered as God's punishment or a warning to the ruler. Historical
records of dust observations are preserved from as early as the first century BC
(Chun et al. 2008 ). Two millennia later, Alexander von Humboldt ( 1807 ) discussed
how dust particles could be taken up into the atmosphere after viewing a wind
spout in South America. Charles Darwin ( 1846 ) published the first scientific record
of intercontinental transport of Saharan dust across the Atlantic Ocean. A Royal
Society Colleague of Darwin had encountered Saharan dust along the African coast
transported by the Harmattan winds much earlier, but he did not recognise that the
'troublesome sensation of prickling on the skin' he felt was probably caused by dust
particles (Dobson 1781 ). Samples of dust collected by Darwin on the Beagle near
the Cape Verde Islands were sent to Berlin, where they were analysed with regard
to their microscopic content. Ehrenberg hypothesised that at least parts of the dust
originated from a dry lake due to findings of freshwater diatoms and terrestrial plant
material, thereby excluding volcanic sources as previously suggested (Ehrenberg
1849 ). In 1925 Sutton published a paper on the meteorology of haboob dust storms
in Sudan, including a limited climatology based on surface station data. A few years
later, Semmelhack ( 1934 ) described some details of the long-range transport and
deposition patterns of mineral dust over the tropical Atlantic.
An important milestone of modern dust research was the publication of The
physics of blown sand and desert dunes by Bagnold in 1941, which has been a
main reference in the field of dust uplift ever since. The following 1940s-1960s saw
a number of studies on dust emission and its dependence on soil characteristics (e.g.