Factors favouring precipitation in North Africa: seen from the viewpoint of present-day climatology

Dealing with global and regional climate factors, this paper attempts to illustrate the climatological conditions that prevailed during both the beginning and the end of the postglacial humid period (8000–5000 years ago) in North Africa. In this connection, in situ sources of moisture, advection of water vapour from the south, and advection and production of upper waves or vorticity are emphazised. A type of rain-stimulating meteorological connective system is proposed, resulting in an overlapping of areas with both sufficient summer and winter rain in North Africa. In addition, modern weather sequences are provided as analogue examples of the development of widespread precipitation processes over present-day desert regions