策勒沙漠-绿洲输沙及动力环境特征

利用2012年4月9日—5月9日策勒沙漠和绿洲内部测点的输沙及气象资料,分析了沙漠与绿洲内部沙尘传输的差异性,并从风动力环境上揭示了成因。结果表明:(1)观测期间,通过沙漠测点100 cm(宽)×200 cm(高)断面的沙尘总量为117.5 kg,通过绿洲内部棉田相同断面的沙尘总量为15.1 kg,比沙漠测点减少了87.1%;(2)过渡带和防护林带对风速的消减作用明显,观测期间,沙漠测点起沙风的持续时间为97.4 h,棉田测点仅为18.9 h;(3)观测期间,沙漠测点的总输沙势为114.2 VU,合成输沙势为72.8 VU,合成输沙方向为65.5°;棉田测点的总输沙势为16.1 VU,合成输沙势为15.1 VU,合成输沙方向为104.5°。荒漠过渡带和绿洲防护林通过降低绿洲内部的风速,改变动力环境,削弱沙尘在绿洲区的传输。

Characteristics of sediment transport and dynamical environments in desert-oasis, Qira County

The desert transitional zone and wind break forest were important to keep the stability of the oasis ecosystem and to protect oasis environment through intercepting sediment transport. In this study, the differences of sediment transport between desert and oasis were studied based on the observation data during 9 April to 9 May 2014. Meanwhile, the dynamical environments of desert and oasis were analyzed, so as to provide a reasonable explanation of differences of sediment transport between desert and oasis. Some preliminary conclusions as follows : (1) During observation period, the amount of dust that passed through a section of 100 cm in width and 200 cm in height was 117.5 kg in the desert, and 15.1 kg in the oasis. And the dust flux in the oasis was 87.1% less than that in the desert.(2)The desert transitional zone and wind break forest significantly reduced the wind speed, and the occurrence time of sand-driving wind was 97.4h in the desert, and 18.9h in the oasis during observation period.(3)During observation period, the drift sand potential and resultant sand drift potential were 114.2VU, 16.1VU and 72.8VU, 15.1VU, respectively. And the drift sand potential and resultant sand drift potential in the oasis were 85.9% and 79.3% less than that in the desert. This indicated that the desert transitional zone and wind break forest significantly reduced the intensity of sediment transport.