干旱区生态环境知识资源中心

The present study aims to improve our understanding of the spatiotemporal variability of the dust emission occurrences and intensities over the Middle-East and North-Africa (MENA). We present monthly and yearly MENA’s dust emission potential (MENA-DEP) ranging between 0 and 1, which are derived from the hourly simulated sandblasting fluxes between 2011 and 2014. These simulations are carried out using the dust emission parameterization scheme proposed byAlfaro and Gomes (2001), which has already proven its efficiency over the MENA region. The computation is undertaken by considering the wind speed and the soil/surface variables from different datasets as input data. Results obtained in this study show a high spatiotemporal variability of the dust emission, where the average percentage proportions of the low, moderate and high dust emission areas from the total MENA’s desert lands are respectively 62%, 32%, and 7%. In short, a minor area of similar to 1.6 million km(2) contributes to the high dust emissions, thereby affecting the global environment. The maximum dust emission activities are observed during winter-spring seasons over North-Africa and during summer season over the Middle-East Similar to the published studies, these emissions occur intensely in areas of abundant fluvial deposits, such as the Bodele depression in Chad, the Qattara, depression in Egypt, the Chottel-ferld in southern Tunisia, the ChottMelghir in northerneast Algeria, the Nubian desert in Sudan, the Sistan basin in Iran-Afghanistan, the Makran desert in Pakistan and the Thar desert in northwest India, and less in areas of coarse sand sediments (seas sand and dune systems), such as the Rub’al Khali desert in the southern Arabian Peninsula, the Grant Erg occidental in Algeria, the Great sand sea in Libya. Specifically, the Chad basin including the Bodele depression is conclusively found to be the dustiest region in the world. Further, a few new dust source areas are revealed in this study, such as the Nogal valley in the Horn of Africa region, the Aljafra plain and the Nafusa mountain slopes at the Tunisia-Libyan borders, the northwestern slopes of the Tibesti mountains at the Libya-Chad border, the Sebkhet te-n-Dghamcha region in Mauritania/Western-Sahara border, the Wadi Howar in central Sudan, and the west Algeria region bordering with Morocco. All these dust sources exhibit high spatial and temporal heterogeneity in dust emissions, which are tightly coupled to atmospheric processes, geomorphology and sediment deposition. (C) 2016 Elsevier B.V. All rights reserved.