英亚app

基于TINDVI的伊犁河谷草地覆盖变化
, , , ·,

(yilishifandaxue ziyuanyushengtaiyanjiusuo, xinjiang yining 835000)

;;;

Dynamics of Grassland Coverage in Ili River Valley Based on TINDVI
YAN Junjie, CHEN Chen, ZHAO Yang, SHAMULI·Davutibai, LIU Haijun

(institute of resources and ecology, yili normal university, yining 835000, china)

;;;

备注

草地覆盖动态变化是全球变化研究的重要内容。选择草地类型丰富多样的伊犁河谷为研究区,在MODIS NDVI数据的基础上,计算获得时间累积归一化植被指数(Time-integrated normalized difference vegetation index,TINDVI),以TINDVI为参考指标,借助GIS空间分析技术及Mann-Kendall非参数统计检验等方法,对2000—2018年伊犁河谷草地覆盖的动态变化进行了分析,并探讨了TINDVI与代表植被生长最好水平的NDVImax的比较优势。得出如下结论:(1)利用生长季内NDVI累加计算得到的伊犁河谷草地TINDVI的多年平均取值范围为0~11,空间上TINDVI海拔分异明显,全区75.69%的草地TINDVI>4.0;(2)2000—2018年伊犁河谷草地TINDVI总体呈非显著增加趋势,而NDVImax总体呈非显著减小趋势,两者年变化速率分别为0.015和-0.000 1; 空间上,全区73.95%草地的TINDVI有所增大,而57.28%草地的NDVImax发生减小,42.58%的区域TINDVI与NDVImax变化趋势相反,草地植被生长过程的年际变化是两者变化趋势有所差异的原因;(3)伊犁河谷草地覆盖变化与降水和气温相关性的海拔分异明显,相对于NDVImax,草地TINDVI对降水和气温变化响应更敏感,且与降水相关性明显高于气温;(4)草地植被生长过程的年际变化也是草地变化的重要方面,生长季内NDVI累加得到的TINDVI在量化草地覆盖变化上具有一定应用价值。
Dynamics of grassland vegetation is one of the important contents of global change research. Ili River Valley, which is rich in grassland types, was selected as the research area. On the basis of MODIS NDVI, the time integrated normalized difference vegetation index(TINDVI)was calculated. Taking TINDVI as the indicator of grassland coverage, we used the spatial analysis of GIS and method of Mann-kendall nonparametric test to analyze the dynamics of grassland coverage in Ili River valley from 2000 to 2018, and discussed the comparative advantage between TINDVI and NDVImax(NDVImax represents the best growing status of vegetation in a growing season). The results showed that:(1)the annual-averaged range of TINDVI, calculated by NDVI accumulation in a growing season, of the grassland in Ili River Valley was 0~11; spatially, the difference of TINDVI along the elevation was obvious, and the proportion of grassland with TINDVI>4.0 reached up to 75.69% in the whole area;(2)in the period 2000—2018, the grassland TINDVI in Ili River Valley showed a non-significant increasing trend, compared with a non-significant decreasing trend of NDVImax; the annual changing rate was 0.015 and -0.000 1 for TINDVI and NDVImax, respectively; spatially, 73.95% of the grassland TINDVI increased, and 57.28% of the NDVImax decreased; the proportion of grassland showing opposite changing trends in TINDVI and NDVImax reached up to 42.58%, and the interannual changes in the growth process of the grassland vegetaion was the reason for the opposite changing trends;(3)the changes of the correlation between grassland coverage and precipitation and temperature along the elevation in the Yili River Valley was obvious; compared with NDVImax, TINDVI was more sensitive to changes in precipitation and temperature, and the correlation between grassland coverage and precipitation was higher than that of temperature;(4)the interannual change of the growing process is also an important aspect of grassland change, and the TINDVI accumulated from NDVI in the growing season has certain application value in quantifying grassland coverage change.
英亚体育 英亚体育 英亚体育 英亚体育 英亚app