Mineral dust aerosol may both scatter and absorb solar radiation, and
the silicaceous fraction will strongly absorb terrestrial radiation in
the 8--14 
m wavelength region ( Penner et al.
[1993a]). Anthropogenic contributions to atmospheric dust loadings
include land-use changes (deforestation and
desertification). Long-range transport of Saharan dust to the western
Atlantic Ocean is associated with dust storms that lift material above
the boundary layer, and subsequent transport pathways that are
conducive to preventing significant mixing and removal of smaller
particles to the surface. Long-range transport of Asian dust to the
Pacific Ocean has also been documented ( Zhang et al. [1993a] and
Schneider et al. [1990]).
Dust plumes are often clearly seen in satellite imagery, and thus dust might be expected to contribute to aerosol radiative forcing. A comparison of measurements made in central Asia of the complex refractive index for atmospheric dust aerosols is presented in Sokolik et al. [1993]; it is pointed out that significant differences in estimates of radiative effects arise due to the considerable range of values for the imaginary part of the refractive index, which is related to light absorption. The presence of other material which is generally suspended with dust (e.g., soot) may also alter the conclusions. The measurements reported by Hansen et al. [1993] of optical absorption by suspended material, including dust and soot, showed that dust contributed significantly to total absorption only during times of active dust production. These authors conclude that a greater optical impact on less-developed regions of the world will be produced from the effects of transported products of fuel combustion than from the effects of desert dust production.
Interestingly, the magnitude and pattern of dust transport to the North Atlantic could be very sensitive to aridity on the North African continent and to shifts in the large-scale atmospheric circulation patterns that frequently transport Saharan dust to the region ( Arimoto et al. [1992]). Thus climate change may have an effect upon dust production and transport, rather than be caused by effects from this type of aerosol.