新疆策勒沙漠-绿洲过渡带水平输沙通量

Horizontal Sand Transportation Flux in the Desert-Oasis Ecotone in Cele,Xinjiang

新疆策勒沙漠-绿洲过渡带的天然植被对绿洲内部的农田起到了很好的保护作用,具有良好的防风阻沙效益。对策勒沙漠-绿洲过渡带的流沙地、半固定沙地、固定沙地的水平输沙通量和风速进行了分析。结果表明:(1)近地表的输沙通量和平均风速从流沙地至半固定、固定沙地大幅度地减少。在0~202.5cm高度范围,半固定沙地、固定沙地水平输沙通量相比流沙地分别少了56.91%、90.23%;在0~70cm高度范围内,输沙通量分别少了85.31%、99.55%;(2)平均风速越大,半固定沙地、固定沙地相比流沙地的输沙通量减少得愈多,流沙地、半固定沙地、固定沙地近地表输沙通量与平均风速分别服从指数、线性和多项式函数关系;(3)策勒沙漠-绿洲过渡带的有效宽度不小于1.74km,才能保护绿洲免受风沙危害。

The natural vegetation in the oasis-desert ecotone in Cele has good role in the protection of the farmland in the oasis.In order to analyze the protection effect of different landscape types,the sand transportation flux in horizontal direction in shifting sandy land,semi-fixed sandy land and fixed sandy land in desert-oasis ecotone in Cele is analyzed.The results showed that the sand transportation flux near ground surface and average wind speed reduced significantly from shifting sandy land to semi-fixed and fixed sandy lands.At 0-202.5 cm height,the sand transportation flux in semi-fixed and fixed sandy land were less than in shifting sandy land by56.91% and 90.23%.At 0-70 cm height,the sand transportation flux in semi-fixed and fixed sandy land were less than in shifting sandy land by 85.31% and 99.55%.When the average wind speed is greater,the sand transportation flux in semi-fixed and fixed sandy lands would reduce more compared with that in shifting sandy land.The exponential,linear and polynomial functional relationships were found between sand transportation flux near ground surface and average wind speed in shifting sandy land,semi-fixed sandy land and fixed sandy land,respectively.In order to protect oasis against wind and sand disasters,the effective width of desertoasis ecotone should not be less than 1.74 km in Cele.