近20年来新疆阿勒泰地区植被动态变化及其对气候与地形的响应

Vegetation Dynamic Change and Its Response to Climate and Topography in Altay Region of Xinjiang in Recent 20 Years

植被在生态环境监测中有着极其重要的意义,探讨植被覆盖变化可为区域生态环境保护工作提供重要参考。利用多源遥感长时间序列数据、分离趋势和季节项的突变点方法像元突变监测、地形位分析及地统计等方法,对新疆阿勒泰地区2000—2019年间植被覆盖动态进行遥感变化监测。实验结果表明:(1)研究期间,2003—2009年植被突变像元数逐年增多,2009年以后突变像元数逐渐减少,同时在监测出的7类植被像元突变趋势类型中,由退化后转变为增长类的像元突变数最多,干扰退化和持续退化类较少;(2)多源数据植被覆被年际变化曲线显示,植被覆盖动态变化出现先减少后增加的趋势,其中,2000—2008年时段总体呈现退化趋势,2008—2019年时段呈现明显改善趋势,且退化大于改善;(3)高程大于900 m、坡度大于15°的东坡(北转东和南转东)为植被覆盖变化退化类型的优势地形位,约占62.4%,研究区植被覆盖改善并不明显,需继续加大研究区生态环境保护。

Objectives:Vegetation plays an important role in ecological environment monitoring.Studying vegetation cover change can provide reference for regional ecological environment protection.The region of Altay in Xinjiang belongs to the ecological function zone of water conservation mountain grassland,with rich natural resources and beautiful scenery.However,the ecological environmental problems were gradually emerging under the national development strategies.Therefore,monitoring the dynamics of vegetation change in the area with multi-source remote sensing data is necessary to explore the relationship between the economic development and ecological environment protection.Methods:This paper uses multisource remote sensing long time series data with breaks for additive seasonal and trend,topographical position and geostatistical analysis methods to monitor the vegetation cover dynamics in Altay of Xinjiang,China during 2000—2019.Results:This paper processed large number of multisource remote sensing data along with human activity data and showed that during the study period,the number of vegetation breakpoints increased year by year from 2003 to 2009,and then gradually decreased after 2009.Meanwhile,seven types of vegetation breakpoint trends were detected,among them,the more number of breakpoints from degradation to growth type was identified,and the types of disturbance degradation and continuous degradation were less.From the interannual change curve,the dynamic change of vegetation coverage showed a trend of first decreasing and then increasing,that is,the vegetation coverage showed a degradation trend from 2000 to 2008 and a significant improvement trend from 2008 to 2019,and the degradation was greater than the improvement.Meanwhile,the east slope with an elevation of more than 900 m and a slope of more than 15°(from north to east and from south to east) is the dominant topographic location of vegetation degradation type,accounting for 62.4%.Conclusions:The protection of ecological environment in Altay of Xinjiang still needs to be further strengthened and effective protection measures should be taken.