生态学报2018，Vol.38Issue(6)：1885-1896,12.DOI:10.5846/stxb201701150122
近30年中国陆地生态系统NDVI时空变化特征
Spatiotemporal variations of NDVI in terrestrial ecosystems in China from 1982-2012
摘要
Abstract
Vegetation,an important component of terrestrial ecosystems,tells the story of the ecological response to climate change.In the context of climate change,vegetation changes have directly affected substance exchanges and energy balance of regional land-atmosphere interaction processes.Additionally,in China,the vegetation activity of varied terrestrial ecosystems has responded to global climate change in significantly different ways.As a vital remote sensing indicator,the normalized difference vegetation index (NDVI) reflects vegetation growth and coverage,and time series analysis can describe the temporal evolution and spatial variability of vegetation very well.Thus,studying the spatiotemporal variation of NDVI in terrestrial ecosystems not only reveals the response of vegetation in those ecosystems to climate change,but can provide a scientific basis for action on climate change and ecological considerations in an increasingly urbanized country like China.Based on the Global Inventory Modeling and Mapping Studies (GIMMS) NDVI3g dataset for 1982-2012,and the macro structure data of the Chinese terrestrial ecosystem,this study utilized one-dimensional linear regression,ensemble empirical mode decomposition (EEMD),and correlation analysis to examine spatiotemporal variation in the NDVI of each terrestrial ecosystem in China.It also analyzed the relationship between NDVI and climate events over a recent 30-year period.The results show that the average normalized difference vegetation index (ANDVI) and maximum normalized difference vegetation index (MNDVI) increased (0.0029/10 a,P＜0.05 and 0.0076/10 a,P＜0.01,respectively) over the same period.These phenomena indicate the activity of vegetation strengthened in China.In addition,owing to its sensitivity to water-thermal factors,MNDVI can be a useful supplement for monitoring vegetation change.Furthermore,the areas with significant increases in vegetation activities were mainly the farmland and forest ecosystems in the eastern monsoon region,and the areas with significant decreases in vegetation activities were mainly the forests in Northeast China and the desert ecosystem in Northwest China.With ANDVI and MNDVI showing linear trends at different significance levels,the NDVIs of the farmland,forest,grassland,and water and wetland ecosystems showed a general upward trend with large fluctuations,while the NDVI of the desert ecosystem decreased,with obvious vegetation degradation.However,EEMD detected an inflection point among the trends in the five ecosystems that was distinct from the linear trend.This occurred in the 1990s and early 21st century when the NDVI trend shifted from increasing to decreasing.The decomposed results indicated that the NDVI of the ecosystems had oscillation characteristics on an inter-annual (1.9-7.6 years) and an inter-decadal (10.7-22.2 years) scales,with the former being statistically more prominent.The increasing spatial heterogeneity of the NDVI of different terrestrial ecosystems also showed inter-annual periods of 2.1-2.7 years,with increasing regional differences in vegetation activity.Furthermore,the short period-pulsation of the air-sea system from the E1 Ni(n)o-Southern Oscillation and solar activity influenced vegetation activity via climatic factors,which was evidently related to the oscillation characteristics in all ecosystems.关键词
陆地生态系统/NDVI/集合经验模态分解/时空变化/振荡周期/残差趋势Key words
terrestrial ecosystem/NDVI/ensemble empirical mode decomposition/spatiotemporal variation/oscillation period/residual trend引用本文复制引用
刘可,杜灵通,侯静,胡悦,朱玉果,宫菲..近30年中国陆地生态系统NDVI时空变化特征[J].生态学报,2018,38(6):1885-1896,12.基金项目
国家自然科学基金项目(41661003) （41661003）
宁夏自然科学基金项目(NZ16010) （NZ16010）
宁夏高等学校科研项目(NGY2016074) （NGY2016074）
宁夏大学研究生创新项目(GIP2017005) （GIP2017005）
