黄河流域植被指数对气候变化的响应及其与水沙变化的关系

Response of Vegetation Index to Climate Change and Their Relationship with Runoff-Sediment Change in Yellow River Basin

[目地]研究流域植被对气候变化的响应及其与水沙的关系,为黄河流域生态环境政策调整提供科学依据。[方法]基于归一化植被指数(GIMMS NDVI)、气温、降水和径流量、输沙量数据,利用线性回归和相关分析方法分析了黄河流域NDVI时空变化和对气温与降水的响应,及其与径流量和输沙量关系。[结果]①1982—2015年黄河流域及上、中游流域NDVI均呈显著线性增加趋势,中游流域增速最快,显著增加区域面积也最大。②1982—2015年黄河流域NDVI与年平均气温、年降水量呈显著正相关面积分别占22.39%和21.99%,集中分布在中北部区域。③2000—2015年黄河流域总体和上游流域年径流量均表现出增加趋势,上游和中游流域输沙量呈下降趋势。黄河流域水沙关系变化是多种因素共同作用的结果。[结论]气候变化背景下黄河流域1982—2015年植被总体呈改善趋势,但具有明显空间差异特征,植被变化与河流径流和输沙变化关系尚待进一步研究。

[Objective]The response of vegetation changes to climate change and their relationship with runoff and sediment was studied in order to provide the basis for the environment policy adjustment of the Yellow River basin.[Methods]The global inventory modelling and mapping studies normalized difference vegetation index(NDVI),as well as temperature,precipitation,runoff,and sediment transport data,were used to study the spatial and temporal variation of NDVI in the Yellow River basin.The linear trend method and correlation analysis methods were utilized.The characteristics of the response of the spatial and temporal variation of NDVI in the Yellow River basin to temperature and precipitation,as well as the impact on runoff and sediment transport,were examined.[Results]①From 1982 to 2015,the NDVI in the Yellow River basin and the upper and middle reaches of the river basin showed a significant linear increase trend.The middle reaches had the maximum growth rate and the maximum increase in area.②The area of NDVI in the Yellow River basin was significantly positively correlated with annual average air temperature and annual precipitation,accounting for 22.39%and 21.99%,respectively,and concentrated in the central and northern regions.③The annual runoff in the Yellow River basin and the upper reaches showed an increasing trend,and the sediment transport volume in the upper and middle reaches showed a decreasing trend,from 2000 to 2015.The relationship between water and sediment in the Yellow River basin was the result of a variety of factors.[Conclusion]Under the background of climate change,the vegetation in the Yellow River basin showed an improvement trend during 1982—2015,but it had evident spatial heterogeneity.The relationship between vegetation change and river runoff and sediment transport requires further study.