基于kNDVI的黄河流域植被覆盖时空变化及气候驱动分析(2001-2020)

[Objective]The Yellow River Basin(YRB)is a fundamental ecological barrier in China and is one of the regions where the ecological environment is relatively fragile.Studying the spatio-temporal variations in vegetation coverage in the YRB and their driving factors through a long-time-series vegetation dataset is of great significance to eco-environmental construction and sustainable development in the YRB.[Method]We sought to characterize the spatio-temporal variation in vegetation coverage and its climatic driving factors in the YRB from 2001 to 2020 by constructing a new kernel normalized difference vegetation index(kNDVI)dataset based on MOD13 A1 V6 data from the Google Earth Engine(GEE)platform.Using Theil-Sen median trend analysis,the Mann-Kendall test,and the Hurst exponent,we investigated the spatio-temporal variation characteristics and future development trends of the vegetation coverage.The climatic driving factors of vegetation coverage in the YRB were obtained via partial correlation analysis and complex correlation analysis of the associations between kNDVI and both temperature and precipitation.[Result]The spatial distribution pattern of kNDVI in the YRB showed that vegetation coverage was high in the southeast and low in the northwest.Vegetation coverage fluctuated from 2001 to 2020,with a main significant trend of increasing at a growth rate of 0.0995/5a.The areas with improved vegetation coverage accounted for 75.89%,the areas with stable vegetation coverage accounted for 22.05%,and the areas with degraded vegetation coverage accounted for 2.06%.The areas with sustainability accounted for 95.41%and the areas presenting"sustainability and improvement"accounted for 73.20%of the total.The response of vegetation to climatic factors was strong in the YRB,with a stronger response to precipitation than to temperature.At the 0.05 significance level,the main driving factors of vegetation coverage in the YRB were found to be non-climatic factors and accounted for 82.60%,which were mainly distributed in Henan,southern Shaanxi,Shanxi,western Inner Mongolia,Ningxia,and eastern Gansu.The area driven by climate factors accounted for 17.40%,mainly distributed in northern Shaanxi,Shandong,Qinghai,western Gansu,northeastern Inner Mongolia and Sichuan.[Conclusion]From 2001 to 2020,the vegetation coverage in the YRB was generally showed improved,and the spatial variations of the vegetation coverage was mainly improved significantly.Non-climate factors were the main driving force of the vegetation coverage in the YRB.Our findings have implications for ecosystem restoration and sustainable development in the YRB.