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›› 2014, Vol. 37 ›› Issue (2): 230-238.

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Vertical distribution of grain size in aeolian flow in Cele oasis-desert ecotone

WANG  Cui1,2,3,4,LEI  Jia-qiang1,2,LI  Sheng-yu1,MAO  Dong-lei1,2,3,ZHOU  Jie1,2,3,Zaynulla  RAHMUTULLA1,2,3   

  1. (1   University of Chinese Academy of Sciences, Beijing  100049, China;2   Xinjiang Institute of Ecology and Geography, Chinese Academy of Science, Urumqi  830011, Xinjiang, China;3   Cele State Station for Field Observation and Research on Desert Steppe Ecosystem, Cele  848300, Xinjiang, China;4    Xinjiang Communication Science Research Institute, Urumqi  830000, Xinjiang, China)
  • Received:2013-07-05 Revised:2013-09-04 Online:2014-03-25

Abstract: Selecting two different underlying surface including mobile sandland and semi-mobile sandland in Cele oasis-desert ectone,Xinjiang,China,via gathering sand grain in 0-1 cm depth on sand bed surface and collecting vertical sand transportation by gradient sand trap in the height of 0-20 cm when it has wind and dust activity,then measureing grain size by using of mastersizer2000,and all of sand granularity parameters were calculated by Folk &Ward’s equation as well as its judgement standard. The result indicates that the sand bed grain size is larger than the vertical’s in wind-sand flux,and the mean sand grain size decreased with the height. In vertical layer of mobile sandland,its mean silt content is about 28.67%,and its very fine sand and fine sand content accout for 62.31% and 8.94% respectively,and medium sand is the least,its content is only 0.08%. The same measuement was been conducted in semi-mobile sandland,the result displays that silt content of semi-mobile sandland is much more than mobile sandland,it is about 32.25%,and very fine sand content decreased to 58.26% correspondingly. Above sand bed surface,milt increase with the vertical height. Adversly,the very fine sand,fine sand and the medium sand decrease with vertical height. Both the mobile sandland and semi-mobile sandland,its grain size distribution displays the same pattern in vertical layers. Sand grain size percentage grows in power function when its size is less than 0.08 mm,and its percentage decreases when its size is larger than 0.08 mm. The mean grain size in aerolian sand transport displays negative correlation with its sorting efficient,skewness and kurtosis,and its sorting efficient displays positive correlation with its skewness and kurtosis. The underlying surface grain is mainly consisted by silt,very fine sand and fine sand,its sorting efficient is high. From mobile sandland to fixed sandland,the wind erosion degree eases,so the mean grain size decreases. The deposition of the study area is derived from wind-blown sand,and the sand grain transportation mainly by saltating and suspending. All in all,the grain size is tiny in Cele oasis-desert ecotone,where is easy to be the sand-storm source,so it’s necessary to prevent and govern local sand movement.

Key words: vertical distribution of grain size, different grain size group, wind-blown sand environment, Cele oasis-desert ecotone

CLC Number: 

  • P931.3