为揭示乌兰布和沙漠不同下垫面冬季沙尘通量的垂直分布,在野外实地监测的基础上对乌兰布和沙漠3种下垫面冬季输沙量进行测量分析。结果表明:近地表0~100 cm高度内冬季输沙量流动沙丘 > 梭梭固定沙丘 > 白刺半固定沙丘。各下垫面输沙量随高度呈下降趋势,流动沙丘、白刺半固定沙丘、梭梭固定沙丘符合幂函数分布,流动沙丘、梭梭固定沙丘输沙量集中于0~20 cm高度,白刺半固定沙丘集中于0~40 cm高度。风沙流幂函数通量系数a、b与粒径< 0.1 mm和粒径 >0.5 mm颗粒含量负相关,与粒径0.1~0.25 mm颗粒含量正相关,与粒径0.25~0.5 mm颗粒含量不相关。沙粒跃移高度在流动沙丘、白刺半固定沙丘和梭梭固定沙丘分别集中于0~3.59、0~4.33和0~2.36 cm;跃移高度与粒径<0.05 mm和0.1~0.5 mm颗粒含量正相关,尤其与粒径0.1~0.25 mm颗粒含量呈指数函数正相关,与粒径0.05~0.1 mm及>0.5 mm颗粒含量无明显相关性。乌兰布和沙漠流动沙丘在冬季仍具有较大的侵蚀状态,白刺半固定沙丘处于弱风蚀状态,梭梭固定沙丘处于堆积状态,造成地表积沙。在冬季,梭梭固定沙丘仍然发挥着防风固沙的能力,成为冬季固定风沙的重要防线。
In order to reveal the vertical distribution of dust over different underlying surfaces in the Ulan Buh Desert in winter, the sediment discharge of 3 kinds of underlying surfaces were analyzed based on the actual monitoring data in winter. The total sediment discharge of 0-100 cm height in winter was mobile dune > fixed dune > semi-fixed sand dune. The sediment discharge over 3 kinds of underlying surfaces all decreased with height and conformed to power function distribution. The sediment discharges over mobile dune, fixed dune were concentrated in 0-20 cm height and the sediment discharge over semi-fixed sand dune was mainly concentrated in 0-40 cm height. The coefficients a and b was negatively correlated with the concentration of < 0.1 mm particles and >0.5 mm particles, and was positively correlated with the concentration of 0.1-0.25 mm particles, and no correlation with the concentration of 0.25-0.5 mm particles. The saltation heights over mobile dune, fixed dune and semi-fixed sand dune were 3.59 cm, 2.36 cm and 4.33 cm, respectively. There was a positive correlation between the saltation height and the concentrations of <0.05 mm and 0.1-0.5 mm particles, especially there was an exponential function relationship with the concentrations of 0.1-0.25 mm particles, but there was no significant relationship with the concentrations of 0.05~0.1 mm and >0.5 mm particles. The mobile dune in the Ulan Buh Desert was still in serious erosion in winter, and semi-fixed sand dune was basically stable, and fixed dune was in the accumulation state. Fixed dune was still play a role in sand fixation in winter.
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