香日德—柴达木河流域NDVI时空变化及其影响因子研究

Temporal and spatial variation of NDVI and its in⁃ fluencing factors in Xiangride-Qaidam River Basin

摘要:

【目的】探究香日德—柴达木河流域植被覆盖度变化及其与气象因子的关系。【方法】以 2000-2021 年归一化植被指数（NDVI）为基础并结合气温、降水数据，采用植被覆盖转移矩阵、ArcGIS 空间分析和数理统计等方法 ，分析了该流域 NDVI 的时空变化趋势及其对气温和降水的响应 。 【结果】（1）香日德—柴达木河流域近 22 年 NDVI 整体呈现出增加趋势，增速为 0. 0071/a；2010 年 NDVI 值最大，为 0. 256，2001 年 NDVI 值最低，为 0. 180，均值为 0. 220；（2）研究区内中覆盖、较高覆盖及高覆盖植被的覆盖面积增加，裸地和低覆盖植被的覆盖面积减少，植被由东南向西北逐渐退化，在海拔 4 000~4 500 m 处植被覆盖度最高；（3）气温和降水均对 NDVI 有一定的影响，气温升高限制了 NDVI 增长，而降水的增加有助于提高 NDVI。【结论】研究区近 22 年生态环境明显改善，植被整体恢复较好，气温、降水及海拔综合影响该地区的植被生长。

Abstract:

【Objective】 In order to explore the change of vegetation coverage and its relationship with meteoro- logical factors in the Xiangride -Qaidam River Basin，【Method】 The normalized different vegetation index （NDVI） from 2000 to 2021conjunction with the temperature and precipitation data，were applied to analyze the spatial and tem- poral trends of NDVI and its response to temperature and precipitation using the vegetation cover transfer matrix， ArcGIS spatial analysis and mathematical statistics.【Result】 The results showed that：（1） The overall NDVI of Xiangride -Qaidam River Basin showed an increasing trend in recent 22 years，with a growth rate of 0. 007 1/a. The highest NDVI value was 0. 256 in 2010，and the lowest NDVI value was 0. 180 in 2001，with an average of 0. 220. （2） In the study area，the coverage area of medium coverage，higher coverage and high coverage vegetation increased， while the coverage area of bare land and low coverage vegetation decreased. Vegetation gradually degenerated from southeast to northwest. The highest vegetation coverage was found at 4 000~4 500 m above sea level.（3） Both tem- perature and precipitation had a certain impact on NDVI. The increase of temperature limits the growth of NDVI， while the increase of precipitation helps to improve NDVI.【Conclusion】 In recent 22 years，the ecological environ- ment of the study area has been significantly improved，and the overall vegetation recovery is good. Temperature，pre- cipitation and altitude have comprehensively affected the growth of vegetationin this area.