【摘要】 以库姆塔格沙漠腹地的羽毛状沙垄为床面,通过风季实地观测与分析,研究了羽毛状沙垄的近地面风况、粒度特征及风沙流结构等。结果表明:羽毛状沙垄近地面风况具有明显的季节性,冬季盛行东风,其他季节盛行东北风;全年平均风速5.94m.s-1,大于起沙风频率占总量的46.76%;新月形沙垄粒度变化在1.22~1.86之间,分选较好,垄间沙埂粒度变化在1.35~2.11之间,风选属于中偏差;随着风速的增大,地面以上0—2cm高度层所含沙量有明显减少的趋势,2—20cm所含沙量有增加的趋势,0—20cm所含沙量占总输沙量的92.28%以上;在地面以上0—40cm高度内,输沙率同2m高处1min平均风速为幂函数关系,不同性质的地表对输沙率有较大的影响;羽毛状沙垄的风速变化表现为新月形沙垄和垄间沙埂不同部位气流的增速和减速,风向变化表现为同风场下沙垄与沙埂风向夹角的存在。更多还原

【Abstract】 Through on-the-spot observation in windy season and data analysis a study on the wind regime,grain size characteristics and wind-sand flux structure near sand bed of feather-shaped sand ridge in the Kumtag Desert was conducted.The wind regime was seasonally changing,the E-dominated wind blew in winter and the N-E dominated wind blew in the other seasons.The annual average wind speed was 594 m·s-1 in the area,and the frequency of sand-blowing threshold wind was 46.76%.The grain size of barchan ridge was within 122186,belonging to better rating,and the grain size between sandy ridges was within 135211,belonging to weaker rating.With the increasing of wind speed,the sand content in wind-sand flux aboveground 02 cm reduced obviously;the content within 220 cm tended to increase,occupying more than 9228% of the total.The sand-transporting rate of 040 cm height had power function relation with the average wind speed per minute at 2 m,in addition it was influenced strongly by different landforms.The wind regime over feather-shaped sand ridges appeared on the wind-speeding and wind-slowing in different positions of barchan and lowland,also on the variation of wind direction angle between that faced sand ridges.更多还原