敦煌鸣沙山月牙泉景区高大沙丘短期动态变化特征

Short-term Dynamic Change of Mega-dunes around the Crescent Spring in Dunhuang

鸣沙山月牙泉以其独特的"沙丘抱泉,泉映沙丘"景观享誉中外,其形成与保存备受关注。通过野外气象站定位监测与全站仪测量等手段,对鸣沙山月牙泉景区短期沙山变化进行全面系统研究。结果表明:无论年内还是整年监测期,月牙泉周边高大沙丘变化趋势与多年航片解析下的南侧线性沙垄北移和北沙山南移形成的合围之势有所不同。首先,沙丘脊线来回摆动,并非一直朝单一方向移动。其次,沙丘坡面表现风蚀或风积,蚀积量与风况、沙源供给、下垫面以及周边障碍物等密切相关。并且,整年监测期内沙丘迎风坡面风蚀,背风坡面风积。此项研究揭示了月牙泉短期高大沙丘的移动规律,可为月牙泉保护提供新思路。

The Crescent Spring is a special scenery, so the study on its formation and preservation attracts more and more attention. In this paper, the data observed by the field meteorological station and the total station were applied to analyze the short-term dynamic change of the mega-dunes around the Crescent Spring. Results showed that the mega-dunes were stable during the observation period, which was different from the former conclusions drawn from the interpreted results of perennial aerial photographs that the longitudinal dunes in the south moved northward,the pyramid dunes in the north moved southward, and the Crescent Spring was threatened. The crest line of the mega-dunes shifted in an oscillating way. Sand erosion or deposition occurred on the dune surface, which was closely related to the wind regime, sand sources, underlying surface, barriers, etc. The observation revealed that sand erosion occurred on the windward slope and sand deposition occurred on the leeward slope. The displacement laws of the mega-dunes around the Crescent Spring were revealed, which could be referred in protecting the Crescent Spring.