2002—2021年雅砻江锦屏一级水电站库区NDVI时空变化及其与气候因子的相关性

Spatial-temporal changes of NDVI and their relationships with climate factors in the reservoir area of Jinping hydropower station(grade 1)on the Yalong River from 2002 to 2021

利用长时间序列的MODIS遥感影像和气象数据,应用归一化植被覆盖度指数(NDVI)、趋势分析、Mann-Kendall统计检验法、相关分析等方法,分析了2002—2021年雅砻江锦屏一级水电站库区植被覆盖的时空分布和变化趋势,对植被覆盖度的变化突变点进行识别,探讨了区域植被覆盖度与气候的关系,解释了可能导致植被覆盖度变化的原因。结果表明:1)近20年来,锦屏一级水电站库区NDVI总体呈增长趋势,海拔3000~3500 m是区域内NDVI最高的区间,NDVI呈现减少主要为近库区沿岸海拔2500 m以下区域,呈现增加的主要集中在库区西南部、西北部及东北部海拔2500~3500 m区域;2)锦屏一级水电站库区蓄水前10年植被覆盖度增加速度低于蓄水后10年的植被覆盖度增加速度,并在蓄水完成的2014年出现了转折点;3)锦屏一级水电站库区植被覆盖度的变化与湿度、降水相关,区域内生态保护与恢复工程和库区防护林营造工程的实施也起到了一定成效。

Based on long time series MODIS remote sensing images and meteorological data,we analyzed the spatiotemporal distribution and changes of vegetation coverage and the relationship with climate factor in the reservoir area of Jinping hydropower station(grade 1)from 2002 to 2021.The results showed that:1)In the past 20 years,the vegetation coverage of Jinping hydropower station(grade 1)has shown an increasing trend,in which,the highest vegetation coverage distributed between 3000~3500 m of elevation;The decrease of NDVI was mainly in the coastal area below 2500 m,and the increase was mainly concentrated in the southwest,northwest and northeast of the reservoir area between 2500~3500 m of elevation;2)The growth rate of vegetation coverage in the first 10 years before the water storage in Jinping hydropower station(grade 1)was lower than that in the 10 years after the water storage,and change-point occurred in 2014 when water retain in Jinping grade 1 was completed;3)The changes in vegetation coverage in the Jinping hydropower station(grade 1)hydropower station reservoir were associated with annual humidity and annual precipitation,and benefited from the implementation of ecological protection and restoration projects and the construction of protective forests in the reservoir area.