民勤县沙地的历史变迁与演化(1991—2015年期间)

Historical Change and Evolution of Sandy Land in Minqin(During the Period 1991 to 2015)

采用的主要数据源为分别拍摄于1991、1996、2000、2004、2007、2010年的18景TM影像和拍摄于2015年的3景OLI影像,影像轨道号主要有131/33、131/34和132/33。民勤县大部分地区主要位于131/33。以131/33为主要分析对象,131/34和132/33作为补充。使用ENVI 5.1软件进行数据处理,采用监督分类的方法获得研究区每年的土地利用现状图,并进行面积统计和结果比较分析。实验结果表明:1)民勤县1991—2015年土地利用历史变化有两个主要趋势:东北地区的农田变为沙漠的趋势和中部地区和西南部地区水体、沙漠变为农田的趋势。2)民勤县1991—2015年土地类型之间转化分为3个阶段:1991—1996年土地类型之间转化百分比较高,特别是沙地转换成农田; 1996—2011年土地类型之间转化百分比较低; 2011—2015年土地类型之间转化百分比较高,特别是农田转换成沙漠。导致以上两个结果的原因有人为因素,也有自然因素。尤其是红崖山水库修建以来,人为因素成为主导因素。

Using the main data source for shooting in 1991,1996,2000, 2004, 2007, 2010, 18 King image and shooting in 2015, three OLI images, video track number is 131/33, 131/34 and 132/33. The most of Minqin is located at 131/33 to 131/33 as the main analysis of the object, 131/34 and 132/33 as a supplement. Data processing was carried out using ENVI 5.1 software, and the annual land use status of the study area was obtained by supervised classification method, and the area statistics and result comparison analysis were carried out. The experimental results show that： （1） There are two main trends in the historical use of land use during the period of 1991 to 2015： the farmland in the northeastern region into the desert and the desert in the central and southwest areas into the farmland; （2） The conversion between land types in Minqin between 1991 and 2015 is divided into three phases： the percentage of conversion between land types is higher in 1991-1996, especially the conversion of sandy land into cropland, land conversion between 1996 and 2011 The percentage is low, and the conversion rate between land types in 2011 and 2015 is high, especially farmland is converted into desert; （3） lead to the above two reasons for the results of human factors, there are natural factors. Especially since the construction of the Red Cliff Hill Reservoir, the human factor is the dominant factor.