Oasis microclimate effect on the dust deposition in Cele Oasis at southern Tarim Basin, China
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ORIGINAL PAPER
Oasis microclimate effect on the dust deposition in Cele Oasis at southern Tarim Basin, China Lishuai Xu 1,2,3 & Guijin Mu 1,2,3 & Xiao Ren 1,2,3 & Dejun Wan 4 & Junxia He 1,2,3 & Yongchong Lin 1,2,3
Received: 18 August 2015 / Accepted: 11 January 2016 / Published online: 31 March 2016 # Saudi Society for Geosciences 2016
Abstract Seasonal dustfall was collected in the Cele Oasis at southern Tarim Basin, China, to study the oasis microclimate effect on the spatial distribution of dust deposition. The deposition rates and grain-size parameters were analyzed for each season. In spring, when there is no significant microclimate effect, the deposition rates decreased from the windward margin to the downwind margin. In summer and autumn, when there is a significant microclimate effect, the deposition rates increased slightly from the windward margin to the downwind margin of the oasis, similar with the annual dust deposition pattern. The differences in the dust deposition pattern between seasons indicate that dust deposition is greatly enhanced in the center and downwind directions of the oasis during floating dust days in summer and autumn when there is a significant oasis microclimate effect. Therefore, it can be inferred that the background wind blowing the cold-wet center away from the geometric center of the oasis may be a key factor affecting the dust deposition pattern. The natural dust deposition pattern during winter is uncertain due to deposition from anthropogenic sources. Our results suggest that the dust deposition in the Cele Oasis is affected by a mechanical obstruction effect due to rough surfaces and by an oasis microclimate effect.
* Guijin Mu [email protected]
1
Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, No. 818, Beijing Road, Urumqi, Xinjiang 830011, China
2
University of Chinese Academy of Sciences, Beijing 100049, China
3
Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele 848300, China
4
Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang 050061, China
Keywords Dustfall . Oasis microclimate effect . Grain size . Tarim Basin
Introduction A significant change in surface roughness can enhance dust deposition; rough patches can be regarded as dust-sink areas that can turn into dust sources if vegetation coverage changes (Field et al. 2012; Funk et al. 2012; Hoffmann et al. 2008; Tsoar and Pye 1987). Oases act as sinks for dust, and there have been some theories regarding the factors that increase dust deposition in oasis (Chen et al. 1999; Liu et al. 1994). In general, mechanical obstruction by rough surfaces, oasis microclimate effect (cold-wet island effect), and the influence of human activities can promote dust deposition inside oases (Chen et al. 1999; Liu et al. 1994; Wan et al. 2013). The influence of mechanical obstruction by the rough surfaces on the spatial distribution of dust deposition has been previously studied (Wan et al. 2009; Xu et al.
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