中国亚热带地区植被GPP时空变化及其对GPP_(max)和物候的响应

Spatiotemporal Variation of Vegetation GPP in Subtropical Regions of China and Its Response to GPP_(max)and Phenology

亚热带地区植被具有很强的固碳能力,其动态变化对区域乃至全球尺度碳循环都具有重要影响。基于植被总初级生产力(GPP)和日光诱导叶绿素荧光(SIF)数据,本文采用曲率求导和样条插值提取我国亚热带植被春秋季物候和GPP峰值(GPP_(max)),结合MK趋势检验和偏相关分析,定量分析2001—2018年我国亚热带植被年GPP时空变化特征及其对物候和GPP_(max)的响应。结果表明,研究期间,亚热带地区植被年GPP和GPP_(max)均表现为显著增加的趋势,春季物候和秋季物候则分别表现出不显著提前和显著推迟。偏相关分析结果表明,GPP_(max)和春季物候与年GPP在整个研究区分别为正相关和负相关;除研究区东南部以外,秋季物候与年GPP也表现为正相关。整体而言,研究区内植被年GPP变化主要受到GPP_(max)的控制,其次为春季物候和秋季物候。

Vegetation in subtropical regions has strong carbon sequestration capabilities,and its dynamic changes have significant impacts on regional and even global carbon cycling.Based on the gross primary productivity(GPP)of vegetation and sun-induced chlorophyll fluorescence(SIF)data,the curvature derivative and spline interpolation are used to extract the spring and autumn phenology and GPP peak(GPP_(max))of subtropical vegetation in China,and combined with MK trend test and partial correlation analysis,the spatiotemporal variation characteristics of annual GPP of subtropical vegetation in China from 2001 to 2018 and its response to phenology and GPP_(max)are quantitatively analyzed in this paper.The results showed that during the study period,the annual GPP and GPP_(max)of vegetation in subtropical regions showed a significant increase trend,while the spring phenology and autumn phenology showed no significant advance and significant delay,respectively.The partial correlation analysis results indicate that GPP_(max)and spring phenology are positively and negatively correlated with annual GPP in the entire study area,respectively;except for the southeastern part of the study area,there is also a positive correlation between autumn phenology and annual GPP.Overall,the annual GPP variation of vegetation in the study area is mainly controlled by GPP_(max),followed by spring phenology and autumn phenology.