京津冀植被覆盖度时空演变及其对自然人为变化的响应

Spatiotemporal evolution of vegetation coverage in Beijing-Tianjin-Hebei and its response to natural anthropogenic changes

基于2001~2020年归一化差异植被指数(NDVI)数据,采用像元二分模型最大值合成FVC,通过Sen趋势分析、Mann-Kendall显著性检验、Hurst指数分析预测研究区植被覆盖时空变化,结合气象因子数据应用相关性分析与残差分析在开展植被变化响应分析的基础上新增量化影响因子相对贡献率.结果表明:近20年京津冀地区植被建设良好,全域平均覆盖度为64.5%,植被变化速率介于(-0.0597421~0.039797)/a,植被覆盖波动较大,呈现明显的地理差异变化;京津冀地区FVC时空变化受多因素共同影响,FVC与气温以负相关为主,分布区域贴合行政分区,与城市热岛效应相关;FVC与降水以正相关为主,分布范围贴合生态分区,主要受地理因子调控;人类活动平均残差为-0.00105,负向影响为主;自然与人为因素相对贡献率分别为31.33%和68.67%,人类活动是植被变化的主要驱动因素;未来FVC以改善趋势为主,但城市交界处FVC有下降趋势.研究成果可指导京津冀交界处FVC监测,开展正向人为干预,稳定京津冀环境质量,助推全域生态环境高质量发展.

This study investigated the spatiotemporal changes of vegetation cover in Beijing-Tianjin-Hebei region using Sen trend analysis,Mann Kendall significance test and Hurst index analysis,in which FVC was synthesized using the maximum value of the like element dichotomous model based on the normalized difference vegetation index(NDVI)data from 2001 to 2020.In addition,this study also quantified the relative contribution rate of impact factors using meteorological factor data,correlation analysis and residual analysis.The results indicated that the vegetation construction in Beijing-Tianjin-Hebei region was good in the past 20 years.The average coverage was 64.5%in the whole region,and the vegetation change rate varied from-0.0597421/a to 0.039797/a.However,the vegetation cover fluctuated greatly,which showed obvious geographical differences.The spatiotemporal variation of FVC in this region can be affected by a multitude of factors.The distribution of FVC was negatively correlated with temperature,and its distribution area was close to the geographical boundaries,which was related to the urban heat island effect.Conversely,the FVC showed a positive correlation with precipitation,and its distribution followed ecological zones,predominantly regulated by geographical factors.The average residual error of human activities was-0.00105,mainly exhibiting negative impact.Furthermore,the relative contribution rates of natural factors and human factors were 31.33%and 68.67%,respectively.This revealed that human activities were the major driver of vegetation change.Although a positive trend is expected,a decrease in FVC is also predicted in urban areas.This study can guide the FVC monitoring at the junction of Beijing,Tianjin and Hebei,carry out positive human intervention,enhance the environmental quality of Beijing-Tianjin-Hebei,and boost the high-quality development of the regional ecological environment.