Geographia Technica, Vol 11, Issue no. 1/2016, pp. 13-22

FOUR DECADES PERIOD OF CLIMATIC DATA FOR ASSESSING THE AEOLIAN HAZARD IN THE REGION OF TOUGGOURT (LOW ALGERIAN SAHARA)

Nouar BOULGHOBRA, Naïma KOULL, Tidjani BENZAOUI

DOI: 10.21163/GT_2016.111.03

ABSTRACT: Using the model of Fryberger and Dean (1979), wind data from Sidi-Mahdi airport weather station covering for decades (1975-2014), were analyzed to calculate sand drift potential and its derived parameters: resultant drift potential, resultant drift direction and the wind directional variability index. Results showed that highest potential sand transport corresponded to the spring season (113 Vector Unit). The annual drift potential was about 258 VU; this allowed classifying the region of Touggourt among the intermediate-energy wind environment. Low wind directional variability was detected (0.33), and indicates the wind regime complexity and that winds blow from different directions; this complexity is due to interaction of winter westerlies and summer northerlies and north-easterlies effective winds. Resultant drift direction was estimated to be 320 degrees, and signifies that the moving sands are transported toward the southeast. Climatic data have been used to calculate sand dune mobility index of Lancaster (1988). Results showed that during the four decades period, dune mobility index was well superior to 200 indicating fully active dunes during the considered period. The study showed as well that the sand encroachment risk in Touggourt is certainly related to the physio-climatic environment, but the inappropriate human action could be an amplifying factor of the aeolian hazard.


Keywords: Drift potential, Wind regime, Wind environment, Dune mobility, Sand encroachment

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