2000—2018年云南省易门县植被指数时空动态变化及影响因素分析

Spatiotemporal Dynamic Changes and Impact Factors of Vegetation Index in Yimen County of Yunnan Province from 2000 to 2018

基于Landsat系列数据,将RS与GIS相结合,分析易门县2000—2018年间归一化植被指数(NDVI)时空变化特征,并探讨其影响因素。结果表明,2000—2018年间研究区NDVI值随时间呈波动变化趋势(0.547~0.614),2000—2009年呈增长趋势,2010年陡降,2010—2018年持续增长,高植被覆盖度(0.500≤NDVI值<0.700)区域占优势(占比33.83%~46.41%);县域内NDVI值与地形因子显著相关(P<0.05),随海拔的升高而显著增长,随坡度变化呈先增长后降低的趋势,不同坡向间NDVI值差异显著(P<0.05),阴坡最大,阳坡最小;各乡镇间NDVI值差异较大,十街彝族乡NDVI值最小为0.517,六街街道最大为0.629;NDVI的年际变化受人类活动和气候等因素的共同影响,其与人口数量相关性最大,其次是GDP,年降水量影响最小。

Based on the Landsat data,RS and GIS were used to analyze the spatiotemporal variation characteristics of the normalized vegetation index(NDVI)in Yimen County from 2000 to 2018,and the impact factors were explored.The results showed that NDVI(0.547-0.614)was fluctuated with time from 2000 to 2018,it was increased from 2000 to 2009 and from 2010 to 2018,only was sharply decreased in 2010,and the study area was dominated by high vegetation coverage area(0.500≤NDVI<0.700),which covered 33.83%-46.41%;NDVI was correlated with topographic factors(P<0.05),it was obviously increased with elevation and was firstly increased then decreased with slope,and the differences of NDVI values were significant between different slope aspects(P<0.05),with the maximum on the shaded slope and the minimum on the sunny slope;NDVI was varied among each town,the minimum NDVI was 0.517 in Shijie,and the maximum was 0.629 in Liujie;NDVI was affected by human activities and climate factors,the maximum related factor was the population,the second was GDP,and the minimum was annual precipitation.