新月形沙丘的移动规律及其影响因子—以甘肃河西沙区为例

Abstract

为了探明新月形沙丘的移动规律及其与气象环境因子之间存在的相互关系，在河西绿洲边缘选取了7个典型的样点，用Goolge Earth对各个样点沙丘的形态参数进行测量，并将所得数据与气象环境因子之间进行相关性分析。结果表明：1) 受风速、大风日数等因子的影响，民勤地区沙丘移动最快，移动速度为6.2 m∙a−1，敦煌地区沙丘移动最慢，移动速度为0.8 m∙a−1河西地区平均移动速度为3.7 m∙a−1；2) 受不同气象因子的影响，与2006年相比，河西大部分新月形沙丘背风坡长度呈增加的趋势，背风坡长呈减小趋势；3) 河西地区新月形沙丘均分布在砂砾质滩地或沙粘质滩地上，迎风坡前滩平均长220.0 m，背风坡后滩平均长413.1 m，粗糙的滩地降低了沙丘移动速度；4) 影响沙丘移动的3个主因子为年降水量、年平均风速、年大风日数，其中年降水量在气象因子中的贡献率最大。 In order to explore the movement regularity of the Barchan Dunes and its relationship with me-teorological environment factors, seven typical sample areas were selected at the oasis fringe of Hexi corridor. Google Earth was used to measure the morphological parameters of Barchan Dunes at every sample areas. Sometimes, the correlation was analyzed between the data and meteorological environment factors. The following results were obtained. 1) Affected by the wind speed, annual strong wind days and other factors, the fastest speed of dunes movement was 6.2 m∙a−1 in Minqin desert area. The speed of dunes movement in Dunhuang desert area is slowest at 0.8 m/a. 2) Compared with 2006, affected by different meteorological factors, in most desert area in Hexi corridor, the windward slope length increases and the leeward slope length decreases. 3) Garchan Dunes are located on the flat beach land of clayey sand or gravel quality in the Hexi desert area of Gansu. On the wind of Barchan Dune there is average 220.0 m, and in downwind of Barchan Dunes there is average 413.1 m. The rough beaches lowered the dunes movement speed. 4) The three main factors that affect the dunes dynamic are annual precipitation, annual average wind speed and annual strong wind days, but the annual precipitation has largest contribution rate in all meteorological factors.