李恒 龚文峰 曹凯华 刘月阳 徐铖龙 周莹 徐宏聚

摘要：基于RS和GIS技术，以甘南县2014年 GF-1WFV1影像和2018年GF-1WFV3影像为基础数据源，采用像元二分模型法定量获取研究区域的植被覆盖。研究结果表明，甘南县植被覆盖度整体状况良好，中高盖度和高盖度占据主要地位，呈现递增的趋势，面积比例之和分别为73.39%和87.16%，源于国家推行的退耕还林还草等生态政策，生态环境恶化趋势得到一定缓解。极低覆盖度、低盖度和中盖度植被面积呈现递减趋势，其中中盖度植被面积减少的最多，为439.88 km2。

关键词：植被覆盖度;GF-1;NDVI;甘南县

Abstract： Based on RS and GIS technology， based on Gannan County's 2014 GF-1WFV1 image and 2018 GF-1WFV3 image data source， the pixel coverage of the study area was quantitatively obtained by the pixel binary model method. The results show that the overall coverage of vegetation coverage in Gannan County is good， and the medium-high coverage and high coverage occupy a dominant position， showing an increasing trend. The sum of the area ratios is 73.39% and 87.16% respectively， which is derived from the national implementation of returning farmland to forests. Ecological policies such as grass and the deterioration of the ecological environment have been alleviated. The vegetation coverage of extremely low coverage， low coverage and mid-coverage showed a decreasing trend， with the most reduced vegetation area in the middle cover， which was 439.88 km2.

Key words： Vegetation coverage;GF-1;NDVI;Gannan County

1引言

农牧交错带是指农业区与牧业区之间所存在的一个农牧过渡地带，在这个过渡带内种植业和草地畜牧业在空间上交错分布[1]，生态结构较为简单，对全球环境变化极为敏感。近几十年来，随着全球环境的变化，该区域环境不断恶化，已对當地生态环境和经济发展产生严重影响。据甘南县水务局的相关勘察表明，全县现有水土流失面积占总面积52.7%[2]。植被覆盖度不仅是一个重要的生态学参数，也是控制土壤侵蚀的一个关键因素。因此，开展植被覆盖度的提取研究对当地生态恢复和经济发展都具有积极作用。

植被覆盖度是指植被包括叶、茎、枝在地面的垂直投影占统计区总面积的百分比[3]。植被覆盖度测算方法主要有目测估算法、仪器测量计算法和遥感解译法[4]。相比常规的调查方法，遥感解译法具有观测范围大、获取速度快、花费成本低、干扰因素少等优点[5]，已逐步成为当前学者提取植被覆盖度估算的主流方法。……