Dunes, Wadis, and Desert Landform Processes

Modern desert geomorphology rests substantially on the work of Ralph Bagnold, a British Army engineer and explorer whose fieldwork crossing the Libyan Desert in the 1930s culminated in The Physics of Blown Sand and Desert Dunes, published in 1941. Bagnold identified saltation, the short, ballistic hopping of sand grains along the surface under wind stress, as the dominant mode of aeolian transport, distinct from the finer-grained suspension of dust high into the atmosphere and the slower surface creep of larger grains nudged forward by saltating impacts; he further derived the threshold wind velocity required to set grains of a given size into motion, a formula still used in desert engineering today.