植被碳利用率作为生物圈与大气圈碳循环的关键参数之一,对了解生态系统碳源和碳汇具有重要作用.本文基于MOD17A2H数据,采用Theil-Sen media趋势分析、空间插值以及偏相关分析法,分析2001～2020年西南地区植被碳利用率(Carbon Use Efficiency,CUE)时空分布格局及变化趋势,根据气象数据和数字高程模型(Digital Elevation Model,DEM)数据,重点研究了西南地区植被CUE对气候变化的响应.结果表明:(1)2001～2020年西南地区不同植被类型年内CUE整体呈上升—下降—再上升—再下降的变化特征,整体上各植被类型CUE呈下降趋势,下降速率依次为:灌木＞森林＞草地＞农作物.(2)近20年西南地区植被CUE多年均值约为0.75,植被固碳能力较强,空间上表现出由南部和东北部向西北部递增的空间分布格局,趋势分析表明西南地区植被CUE整体表现为微弱下降趋势.(3)2001～2020年西南地区植被碳利用率与气温、降水以及日照时长均呈负相关关系,整体上西南地区植被CUE主要受气温和日照时长影响,其次为降水.
Spatiotemporal Variation Characteristics of Vegetation Carbon Use Efficiency and Its Driving Factors in Southwest China over the Past 20 Years
As a key parameter of the carbon cycle within the biosphere and atmosphere,vegetation carbon use efficiency plays an important role in understanding ecosystem carbon sources and sinks.This paper analyzed the spatiotemporal patterns and trends of vegetation carbon use efficiency(CUE)in southwest China from 2001 to 2020 using Theil-Sen media trend analysis,spatial interpolation,and correlation analysis based on the MOD17A2H data.This paper focused on the response of vegetation CUE to climate changes in Southwest China using meteorological data and digital elevation model data.The results showed that(1)from 2001 to 2020,the monthly average CUE values for all vegetation types in Southwest China showed a pattern of rising,declining,rising again,and then declining again.Overall,the CUE of all vegetation types demonstrated a decreasing trend,and the decreasing rate was in the order of shrub＞forest＞grassland＞crop.(2)Over the past 20 years,the average annual value of vegetation CUE was about 0.75,indicating strong vegetation carbon sequestration capacity.The spatial distribution pattern revealed an increase in vegetation CUE from south and northeast China toward the northwest.Trend analysis displayed a weak downward trend in vegetation CUE across southwest China.(3)From 2001 to 2020,vegetation CUE negatively correlated with the air temperature,precipitation,and sunshine duration in Southwest China.This implies that the air temperature and sunshine duration were the dominant climatic factors affecting vegetation CUE in southwest China,whereas the impact of precipitation on vegetation CUE was relatively weak.
MODISCarbon use efficiency(CUE)Spatiotemporal variationClimatic factorsSouthwest China
NETL
NSTL
万方数据
