ASSESSING THE MICROPED SIZE DISTRIBUTIONS OF DESERT SOILS ERODIBLE BYWIND

The microped size distribution of erodible soils is one of the main fa ctors controlling the emissions of mineral aerosol. To date, the micro ped size distributions of desert soils in natural field conditions are not well known and thus the existing dust source models cannot be app lied to natural sites. Based on dry sieving and elemental analysis of 26 soil samples collected in arid and semiarid regions, it is shown th at the microped size distributions of these desert soil samples involv e a combination of four major mass size populations. These four size p opulations correspond to salty soils, fine quartz sand, coarse dune sa nd and aluminosilicate silt. We show that the microped size distributi ons of the various desert soils, according to their mineralogical char acteristics, can be calculated by a mixture involving two or three of these four populations. The main held of application for this scheme i s the characterization of the erodible soil size distributions for mod elling the atmospheric dust cycle.