21世纪以来河南省植被覆盖变化及气候驱动解析

借助MODIS NDVI数据和气象插值数据,采用一元线性回归、Hurst指数及相关分析等方法,从年际尺度探讨河南省21世纪以来植被覆盖时空变化规律,并分析其对气候因素的响应特征。结果表明:河南省植被覆盖区域差异较大,NDVI频度呈单峰结构;近16年来,河南省大部分地区植被覆盖呈现增加趋势,10年平均增速约为4%(P0.01),且阶段性明显;河南省植被变化的同向特征强于反向特征,植被覆盖整体上呈持续改善态势,但郑州、洛阳、焦作等市域局部地区存在持续减小现象;年平均温度的上升是平原区植被覆盖增加的主要驱动因子,但升温尤其是年平均最高温度增加抑制了山区植被生长,植被覆盖对气候因子的敏感程度地域异质性明显。

Analysis on the vegetation cover change in Henan Province of China since the 21st century and its climatic driving

Vegetation cover is an important indicator to assess the function of regional environment.In this study,based on the Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI data set and the historical climate observations,the Linear regression,Hurst index and correlation analysis methods were combined to investigate the spatial-temporal change of vegetation cover and its climatic driving in Henan Province since the 21^st century.The results showed that:Overall,the vegetation cover of Henan Province exhibited a pronounced geographical heterogeneity,and NDVI frequency was characterized by a unimodal structure.A majority (84.59%) of Henan Province displayed an increasing trend in annual NDVI with significant increase in 57.48% of the entire area,with an average rate of 4% per 10 years at the regional scale during the last 16 years.In future,the same characteristics of vegetation cover change would be stronger indicating that vegetation cover in most part of the study area is predicted to increase,while its degradation trends are mainly found in the parts of Zhengzhou City,Luoyang City and Jiaozuo City.In addition,the vegetation cover trends showed a remarkable heterogeneous corresponding to regional climate variations.Increase in the vegetation cover over the plain areas was primarily attributed to the annual average temperature rising,but annual average maximum temperature change was responsible for the decreased vegetation growth in the mountain region.