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Long-term (1984–2012) surface observations from 70 stations in the Saharaand Sahel are used to explore the diurnal, seasonal and geographicalvariations in dust emission events and thresholds. The frequency of dustemission (FDE) is calculated using the present weather codes of SYNOPreports. Thresholds are estimated as the wind speed for which there isa 50% probability of dust emission and are then used to calculate strongwind frequency (SWF) and dust uplift potential (DUP), where the latter is anestimate of the dust-generating power of winds. Stations are grouped into sixcoherent geographical areas for more in-depth analysis.  FDE is highest at stations in Sudan and overall peaks in spring north of23° N. South of this, where stations are directly influenced by thesummer monsoon, the annual cycle in FDE is more variable. Thresholds arehighest in northern Algeria, lowest in the latitude band 16–21° Nand have greatest seasonal variations in the Sahel. Spatial variability inthresholds partly explain spatial variability in frequency of dust emissionevents on an annual basis. However, seasonal variations in thresholds for thesix grouped areas are not the main control on seasonal variations in FDE.This is demonstrated by highly correlated seasonal cycles of FDE and SWFwhich are not significantly changed by using a fixed, or seasonally varying,threshold. The likely meteorological mechanisms generating these patternssuch as low-level jets and haboobs are discussed

A climatology of dust emission events from northern Africa using long-term surface observations