LARHYSS Journal
Volume 19, Numéro 1, Pages 7-32
2022-03-18
When The Sand Of The Sahara Leaves Its Territory – Mechanism Of Dust Rizing
Authors : Remini Boualem .
Abstract
This paper deals with the mechanism of the uplift of dust from the Sahara in the atmosphere. The first study carried out in 2001 showed that it is at the level of the mega-obstacles of the Sahara that the wind dynamics are very active. So, if there is dust rising, it will be at the level of these rock masses. To answer these hypotheses, we used satellite images taken over the Sahara during the period: 2001-2021. The results obtained showed that the Sahara recorded about 875 dust lifts during the period: 2001-2021. It is these uplifts that can send dust flying over the Atlantic. The years 2017 and 2020 recorded the highest number of dust lifts exceeding 600 days. Three types of dust lifting were highlighted: weak (Duration < 3 days), medium (7 days > duration ≥ 3 days) and strong (Duration ≥ 7 days). We have defined effective uplift as uplift capable of propelling a significant amount of dust into the atmosphere. A map of dust lifting areas in the Sahara has been established. Three foci of dust risings in the Sahara have been located. These are the areas induced by the mega-obstacles: Hoggar-Tassili N'Ajjer (Algeria), Aïr (Niger) as well as Tibesti and Ennedi (Chad).
Keywords
Sahara ; Wind dynamics ; Atlantic Ocean ; Mega-obstacle ; Dust rising
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