基于GEE的石羊河流域植被覆盖变化特征及其影响因素分析

Analysis of Vegetation Cover Change Characteristics and InfluencingFactors in the Shiyang River basin based on GEE

植被作为陆地生态系统的重要组成部分,常被用作评估气候变化和生态恢复成效的指标。以石羊河流域为研究对象,基于Google Earth Engine (GEE)平台采用Theil-Sen趋势分析和MannKendall检验(TS-MK)、Hurst指数揭示植被覆盖变化特征;采用偏相关分析、残差分析和地理探测器探究植被覆盖变化的影响因素。结果表明:2001~2020年间石羊河流域植被NDVI呈现波动增长趋势,增长率为0.023/10 a;呈显著增加趋势和显著减少趋势的面积占比分别为72.32%和2.40%。未来植被NDVI变化趋势保持一致(Hurst>0.5)的面积占比为63.84%,其中持续性显著增加的面积占比最大,为47.37%。偏相关分析结果表明降水对植被生长的影响较强,而温度、太阳辐射和饱和水汽压差的影响相对较弱。残差分析结果表明气候要素和人类活动影响下植被NDVI呈显著增加趋势的面积占比分别为21.59%和60.07%,石羊河流域的植被变化主要受人类活动的积极影响。此外,地理探测器的结果表明植被NDVI的空间分布主要受水热条件分布特征的影响。该研究结果有助于深化对植被覆盖变化影响因素的认识,为石羊河流域生态保护提供借鉴。

As an important part of terrestrial ecosystems,vegetation is often used as an indicator to assess the effectiveness of climate change and ecological restoration.In this study,the Shiyang River Basin is taken as an example,Theil-Sen and Mann-Kendall models,and the Hurst index were used to analyze the change characteristics of vegetation cover.The correlation analysis,residual analysis and Geodetector were used to explore the influencing factors of vegetation cover change.The results showed that the vegetation NDVI demonstrated a fluctuating but upward trend from 2001 to 2020,with a rate of increase of 0.023/10 a.Areas with significant increased and significant decreased accounted for 72.32%and 2.4%,respectively.Areas with sustainability(Hurst>0.5)accounted for 63.84%of the entire area,among which 47.37%showed continuously significant increasing trend.The correlation results between NDVI and climatic factors indicated that the impact of precipitation was particularly significant,and the impacts of temperature,solar radiation and saturated vapor pressure deficit were relatively weak.The area of NDVIpre showed a significant increase trend accounted for 21.59%,while the area of NDVIres showed a significant increase trend accounted for 60.07%,so interannual variation of NDVI in Shiyang River Basin was greatly affected by human activities.Geodetector results showed that the spatial distributation characteristics of water-heat conditions.It is noted that the spatial distribution of NDVI of cultivated land is greatly affected by population density.The results of this study are helpful to deepen the understanding of the driving factors of vegetation change and provide scientific reference for ecological protection and restoration of Shiyang River Basin.