2000—2019年若尔盖高原植被生长季NDVI时空变化特征研究

Spatio-temporal Variation of NDVI in the Vegetation Growing Season of the Zoige Plateau from 2000 to 2019

基于2000—2019年的MODIS-NDVI时间序列数据集,应用趋势分析、变异系数和R/S分析方法,研究若尔盖高原植被生长季NDVI的时空变化特征。结果表明:20年来若尔盖高原87.45%的区域植被生长季NDVI呈改善状态,其中64.70%的区域呈明显改善状态,22.75%的区域呈轻度改善状态。植被生长季NDVI的变异系数均值为0.186 5,整体上若尔盖高原2000—2019年植被生长季NDVI呈中等波动变化状态,中等变化状态等级所占比例最大为33.70%,其次为较低波动变化等级比例,为33.14%。植被生长季NDVI的Hurst指数均值为0.437 2,整体上呈弱反持续状态,弱反持续比例为77.43%,弱持续比例为21.50%。

Based on the MODIS-NDVI time series data set from 2000 to 2019, this paper uses trend analysis,coefficient of variation, and R/S analysis to reveal the spatio-temporal characteristics of NDVI during the vegetation growing season of the Zoige Plateau. The results show that in the past 20 years the NDVI in the vegetation growing season of 87.45% of the Zoige Plateau showed an improvement, of which 64.70% showed a significant improvement and 22.75% showed a slight improvement. The average coefficient of variation of NDVI in the vegetation growing season is 0.186 5. Overall, the NDVI in the vegetation growing season of the Zoige Plateau from2000 to 2019 has a moderate fluctuation state. The proportion of the medium change state grade is 33.70%, followed by the proportion of the lower fluctuation grade is 33.14%. The average Hurst index of NDVI in the vegetation growing season was 0.437 2, showing a weak anti-sustained state as a whole, with a weak anti-sustained ratio of 77.43% and a weak sustained ratio of 21.50%.