艾比湖流域NDVI垂直梯度变化特征
收稿日期: 2014-07-04
修回日期: 2014-11-17
网络出版日期: 2015-03-20
基金资助
国家自然科学基金项目(41130531, 41361045)
NDVI at a Vertical Gradient in the Ebinur Lake Basin, Xinjiang, China
Received date: 2014-07-04
Revised date: 2014-11-17
Online published: 2015-03-20
利用2000-2011年MODIS-NDVI数据分析了艾比湖流域植被变化特征,以MVC法合成年最大NDVI,研究不同尺度下海拔与NDVI的关系。建立了12年的NDVI变化趋势的一元线性回归方程,结合DEM数据,分析了24等分下海拔间的NDVI变化趋势。结果显示:(1)总体上,NDVI与海拔的拟合程度较好,判定系数均大于0.88,随着等分数目减少,判定系数增大,10等分时,海拔与NDVI的相关性最大,为0.97;2 500 m为NDVI的分水岭,该海拔以下区域植被覆盖逐渐增加,以上区域植被覆盖逐渐减少;(2)研究区12年NDVI趋势变化平均值为1.03,总体属轻度改善;1 500 m以上区域植被呈减少态势,1 200 m以下植被呈增长态势;(3)各海拔带内NDVI趋势平均值为-42~54,研究区大部分像元NDVI趋势值较小,植被覆盖情况属于轻度改善和轻度退化。
关键词: 植被覆盖; 垂直梯度; MODIS-NDVI; DEM
邓煜霖, 塔西甫拉提·特依拜, 姜红涛, 张飞, 买买提·沙吾提, 努尔麦麦提江·吾布力卡斯穆 . 艾比湖流域NDVI垂直梯度变化特征[J]. 中国沙漠, 2015 , 35(2) : 508 -513 . DOI: 10.7522/j.issn.1000-694X.2014.00173
Vegetation is the most essential part of terrestrial ecosystem, its temporal/spatial changes in normalized difference vegetation index (NDVI) have been widely used in correlation studies. In this paper, MODIS-NDVI datasets in 2000-2011 are used for monitoring vegetation changes in the Ebinur Lake basin, MVC method is applied to make up the 12-year maximum NDVI, DEM data are divided into six intervals to revealing the relationship between NDVI and altitude; established 12-year NDVI trends by linear regression, analysis the trends of NDVI in different elevation intervals. The results showed that: (1) Overall, NDVI values comply well with elevation in six scales, with R2>0.88, elevation with 10 equal intervals and NDVI have the highest correlation, with R2=0.97; NDVI is increasing with the elevation under 2 500 m, is decreasing above 2 500 m; (2) The average of NDVI trend is 1.03 in the studied area, showing that the overall improvement of eco-environment; and it has a decreasing trend of vegetation above 1 500 m, while it shows a rising trend of vegetation blow 1 200 m in the past 12 years in the studied area; (3) In each scale, the average values of the NDVI trend are in the range of -42-54, indicating that large parts of study area are slightly improved and light degradation. The paper provide a new view to study the NDVI changes under different elevation intervals, it is of significance and value to local ecological environment construction.
Key words: vegetation cover; vertical gradient; MODIS-NDVI; DEM
/
〈 |
|
〉 |