祁连山南坡主要河谷NDVI时空变化及影响因素分析

杨荣荣 曹广超 曹生奎 兰垚 张卓 陈治荣

摘 要：為进一步保护祁连山生态环境及合理开发利用河流沿线的植被资源，该文基于MODIS数据的NDVI产品及DEM数据集，对祁连山南坡主要河流谷地2000—2018年植被生长季的NDVI时空分布特征进行了研究，并提取研究区的主要地形因子，分析其对河流谷地植被生长季NDVI的影响。结果表明：随着河流两侧缓冲区距离逐渐增大，各年份的NDVI值呈现先增加后平稳再减少的分布特点;2000—2018年研究区河谷NDVI的变化趋势基本一致，整体表现出2010年出现了近20年的峰值;祁连山南坡河流谷地NDVI值，从斜坡（16°～25°）至急坡（41°～45°）增加的速率最大，说明该区间为NDVI值突变区间。2000—2018年祁连山南坡主要河流谷地的NDVI时空分布，可能受地形、气温和降水等自然因素影响较大，其受人为干扰因素影响较小，其中降水并非影响研究区河谷植被NDVI分布的主导因素，而气温可能是影响研究区河谷植被NDVI分布的主导因素。在地形因子中，存在较适合植被生长的特定坡度区间，且太阳辐射能量的增加有利于植被的生长。

关键词： 河流谷地， NDVI， 时空分布， 影响因素

中图分类号：Q948

文献标识码：A

文章编号：1000-3142（2021）03-0429-09

收稿日期：2019-07-16

基金项目：国家重点研发计划项目（2017YFC0404304）;青海省科技厅重大专项（2019-SF-A12）;国家自然科学基金（41361005）;青海省自然科学基金（2018-ZJ-903） [Supported by the National Key Research and Development Plan Project（2017YFC0404304）; Key Specitial Founation/Project of Science and Technology Department of Qinghai Province（2019-SF-A12）; the National Natural Science Foundation of China（41361005）; Qinghai Natural Science Foundation （2018-ZJ-903）]。

作者简介： 杨荣荣（1992-），硕士研究生，研究方向为遥感与地理信息系统应用，（E-mail）1370532120@qq.com。

通信作者：曹广超，教授，博士研究生导师，主要从事青藏高原地区环境变化与地理信息系统应用研究，（E-mail）caoguangchao@126.com。

Temporal and spatial variations of NDVI and analysis

of influencing factors in main valleys of southern slope of Qilian Mountains

YANG Rongrong1，2，3， CAO Guangchao2，3*， CAO Shengkui1，2，3， LAN Yao1，2，3， ZHANG Zhuo1，2，3， CHEN Zhirong1，2，3

（ 1. College of Geographical Science， Qinghai Normal University， Xining 810008， China; 2. MOE Key Laboratory of Tibetan Plateau Land Surface Processes and Ecological Conservation， Xining 810008， China; 3. Key Laboratory of Qinghai Province Physical Geography and Environmental Processes， Xining 810008， China ）

Abstract：In order to protect the ecological environment of the Qilian Mountains and utilize the vegetation resources along the river， the spatial and temporal distribution characteristics of NDVI in the main growing valleys of the southern slope of Qilian Mountains on the vegetation growing season from 2000 to 2018 based on the NDVI products and DEM datasets of MODIS data， and extracts the main topographic factors of the study area was  analyzed. The results were as followes： With the increasing distance of buffers on both sides of the river， the NDVI values of each year showed increase first and then level off and then decreased. The trend of NDVI was basically same and the peak of the past 20 years appeared in 2010 in the study area from 2000 to 2018. The NDVI value of the river valley increased from the slope （16°-25°） to the steep slope （41°-45°） in the southern slope of the Qilian Mountains， indicating that the interval is the NDVI value mutation interval. The spatial and temporal distribution of NDVI may be affected by natural factors such as topography， temperature and precipitation， which were less affected by human disturbance factors， and the precipitation did not affect the NDVI distribution， and temperature may be the dominant factor affecting the distribution of NDVI in the valleys of the southern slope of Qilian Mountains from 2000 to 2018. Among the topographic factors， there was a specific slope interval that suitable vegetation growth， and the increase of solar radiation energy is beneficial to the growth of vegetation.

Key words： river valley， NDVI， time and space distribution， influencing factor

陆地是人类进行生产生活的重要场所，而植被又是陆地生态系统中重要的一部分。……