1999-2018年青海省土地退化遥感监测及其驱动力分析

Remote Sensing Monitoring and Driving Force Analysis of Land Degradation in Qinghai Province from 1999 to 2018

[目的]分析青海省土地退化的动态变化趋势及主要影响因素,为该省生态环境建设工程以及防治土地退化提供理论依据。[方法]采用ANUSPLIN插值、趋势分析、Hurst指数、残差分析等方法,利用植被降水利用率(RUE)作为土地退化的监测指标。[结果]①青海省RUE和归一化植被指数(NDVI)空间上主要分布为西北低,东南高。西部主要RUE小于0.004,所占比例40.77%,西北部NDVI小于0.75,所占比例38%。②青海省1999-2006,2006-2012,2012-2018年土地退化各所占比例5.16%,4.25%,14.57%;空间上主要从中部和西部往西北部偏移。③气温、日照时数、平均风速与RUE有明显的正相关,所占比例64%,91%和73%,通过显著性检验的所占比例24%,61%,32%。人类活动对RUE负干扰所占比例为55%。[结论]青海省1999-2018年土地退化表现为先减少后增加,持续性较弱,导致青海省土地退化面积减少的影响因子主要有日照、平均风速和温度,人类活动也是影响退化的一大因素。

[Objective]The dynamic change trend and main influencing factors of land degradation in Qinghai Province was analyzed,in order to provide a theoretical basis for ecological environment construction projects and the prevention of land degradation.[Methods]ANUSPLIN interpolation,trend analysis,Hurst index and residual analysis were employed,and the rainfall use efficiency(RUE)was used as the indicator to monitor land degradation.[Results]①The spatial distribution of RUE and normalized difference vegetation index(NDVI)in Qinghai Province was mainly lower in the northwest and higher in the southeast.The main RUE in the west was less than 0.004,accounting for 40.77%,and NDVI in the northwest was less than 0.75,accounting for 38%.②Land degradation of Qinghai Province in 1999-2006,2006-2012,and 2012-2018 accounted for 5.16%,4.25%,and 14.57%,respectively,which was mainly shifted from the middle and west to the northwest.③Temperature,sunshine hours,and average wind speed were significantly positively correlated with RUE,accounting for 64%,91%,and 73%,and 24%,61%and 32%of them passed the significance test.The negative interference of human activities on RUE accounted for 55%.[Conclusion]Land degradation in Qinghai Province in 1999-2018 decreased initially and then increased,with a weak sustainability.The influencing factors leading to the reduction of land degradation area in Qinghai Province are mainly sunshine hours,average wind speed and temperature,and human activities were also a major factor affecting land degradation.