最近10年来新疆风沙地貌研究进展

Progress in Aeolian Geomorphology Study in Xinjiang since Recent 10 Years

最新研究表明,塔克拉玛干沙漠风沙活动与气温变化呈现"风热同步"现象,虽然其风况类型多样,但整个沙漠处于低风能环境。不同沙丘部位上风沙流输沙量的对数与高度之间表现为线性关系。当气流与沙丘走向斜交时,两侧相同部位输沙率的差异不大,这是线形沙丘保持其动力形态平衡的主要原因之一。古尔班通古特沙漠也处于复合型低能风环境之中,冬季积雪和冻土对沙漠地表形成有利的保护,有效植被覆盖和生物结皮是沙面整体处于稳定状态的重要因素,风沙活动仅存在于沙垄顶部和两坡上部。沙漠中生物结皮发育、种类丰富,其类型和分布具有明显的景观异质性特征。天山北坡和昆仑山北坡的黄土研究揭示,新疆两大沙漠从中更新世以来出现明显的干旱化,沙漠逐步扩大至今天规模。此外,塔里木沙漠公路和古尔班通古特沙漠输水明渠沿线的风沙危害具有明显的时空分异特点。因此,根据工程设施所处地形与地貌部位,可定性判断风沙危害类型与强度,进而确定防治方案和措施。今后新疆风沙地貌学研究应注重研究领域的拓展、研究方法的突破和实验手段的创新3个方面。

The progress of aeolian geomorphology study in Xinjiang reveals that air temperature increase and blown sand occur simultaneously in the Taklimakan Desert. Although there are some different wind types, the whole desert is in a low wind-energy environment. There is a linear correlation between the logarithm of sediment dis- charge at different parts of dunes and the dune height. When airflow crosses obliquely with a linear dune, the difference of sediment discharge between two sides of the dune is not so significant, which is one of the main rea- sons maintaining the balance between wind power and dune shape. The Gurbantonggut Desert is also in a low wind- energy environment, the dune surface is protectively covered by seasonal snow cover and frozen earth in winter, the vegetation and the biotic crust are the important factors maintaining the dune surface stable, and aeolian sand move- ment occurs at dune tops and upper part of dune slopes only. There is obvious landscape heterogeneity of the well developed biotic crust with many types. The study results of loess on the northern piedmonts of the Tianshan and Kunlun mountains reveal that the two large deserts in Xinjiang has been in obvious drought since the mid-Pleisto- cene, since then their areas have been gradually enlarged to the current extent. In addition, there is an obvious spatiotemporal differentiation of aeolian sand disasters along the Tarim Desert Highway and the water-conveying ca- nal passing through the Gurbantonggut Desert. Therefore, the types and intensity of aeolian sand disasters can be qualitatively judged according to landforms and the geomorphologic features along these projects, thus the feasible programs and measures of controlling aeolian san disasters can be taken. For the future, the expansion of research domain, improvement of the research means and innovation of experimental technology about aeolian geomorphology in Xinjiang should be paid great attention to.