柴达木盆地东北部哈勒腾河流域风况特征及其对风沙地貌发育的影响

Characteristics of wind regime and its influences on the development of aeolian landforms in the Haertenghe Reach,northeastern Qaidam Basin,China

风况是影响风沙地貌发育的重要因子,在一定程度上决定了沙丘类型。为探究区域风沙地貌发育与风况之间的关系,对哈勒腾河流域不同区域一个完整年度的风况进行分析。结果表明:流域年平均风速为2.78 m·s^(-1),起沙风集中在春夏季,平均风速为7.78 m·s^(-1),起沙风事件平均持续时间为4.1 h;流域输沙势122—254 VU,属中低风能环境,风向变率0.51—0.58,呈中等风向变率。区域风况表现有所差异,西部为中等风能环境,中部和东部为低风能环境。从西到东沙丘类型由穹状沙丘、新月形沙丘等简单类型向格状沙丘、金字塔沙丘等复杂类型过渡,风况变化与沙丘形态复杂程度具有一致性,沙丘整体沿合成输沙方向自西向东移动。结合风况与沙丘分布,推测流域风沙地貌是东部山体风化碎屑物经河流搬运和风力分选改造形成的。该研究结果对于全面认识区域风沙地貌分异规律以及理解风况与沙丘关系具有重要意义,能够为进一步研究沙丘演化及沙丘间相互作用提供基础资料。

Wind regime is one of the most important factors affecting the development of aeolian landforms.For wind-accumulated landforms(e.g.dunes),wind also determines the dune types partly.In order to explore the relationship between aeolian landforms and wind,we analyzed the wind pattern in different regions of the Haerteng River for a whole year.The results show that the mean wind speed is 2.78 m·s^(-1),and the sand-driving wind mainly occurs in spring and summer with a speed of 7.78 m·s^(-1),and the average duration of sand-driving wind events is 4.1 h.Annual drift potential range from 122 to 254 VU,which generally belongs to the intermediate-low wind environment and the index of directional variability(RDP/DP)is mostly intermediate from 0.51 to 0.58.Regional wind regime is different and the western part is intermediate wind environment while central and eastern are low.From the west to the east,the dune types transform from simple(e.g.dome and barchan dunes)to complex(e.g.reticulate and star dunes)with the variation of wind direction and the dune morphology is consistent with wind pattern.Dunes move generally from west to east along the direction of sediment transport.Combined with wind regime and dune distribution,it is speculated that the aeolian landforms of the basin are formed by weathered debris from the eastern mountain that undergo river transportation and wind modification.This study is of great significance for comprehensive understanding the law of regional wind-sand landform differentiation and the relationship between wind regime and sand dunes.It also can provide basic data for further study about the interaction and evolution of dunes.