2006-2016年岷江上游植被覆盖度时空变化及驱动力

基于MODIS NDVI遥感数据,采用像元二分模型估算岷江上游植被覆盖度,运用一元线性回归分析和稳定性分析方法,研究2006-2016年岷江上游植被覆盖度时空变化格局及稳定性,并分段讨论2008年"5.12汶川地震"对岷江上游植被的破坏程度以及震后植被恢复情况,利用地理探测器模型对岷江上游植被覆盖度影响因子及影响力进行探测,分析岷江上游植被覆盖度变化驱动力。结果表明：（1）2006-2016年岷江上游植被覆盖整体状况良好,植被覆盖总体情况较为稳定,多年平均植被覆盖度为0.79,植被覆盖度大于0.8的区域占整个岷江上游地区面积的69%。（2）2008年"5.12汶川地震"给整个岷江上游植被造成了严重的破坏,植被覆盖度退化区域面积为14013.41 km²,占整个岷江上游面积的57%,2008-2016年岷江上游植被恢复状况良好,植被覆盖度改善区域面积为17390.69 km²,占整个岷江上游面积的71%,岷江上游植被覆盖度已经超过震前水平。（3）岷江上游植被覆盖度主要受海拔、气温、土壤类型、降水4个因子的影响,其解释力均在40%以上;地貌类型、植被类型的解释力在20%-40%之间;坡度、坡向的解释力均小于1%。

Study of temporal and spatial variation and driving force of fractional vegetation cover in upper reaches of Minjiang River from 2006 to 2016

Based on moderate resolution imaging spectroradiometer (MODIS) normalized difference vegetation index (NDVI) remote sensing data, the fractional vegetation cover in the upper reaches of Minjiang River was estimated using a pixel dichotomy model. Furthermore, the temporal and spatial variation pattern and stability of the fractional vegetation cover in the upper reaches of Minjiang River from 2006 to 2016 were studied using univariate linear regression and stability analyses. The damage degree of the vegetation in the upper reaches of Minjiang River and the vegetation restoration after the earthquake are discussed in sections. The influencing factors of fractional vegetation cover in the upper reaches of Minjiang River were detected using the Geographic detector model. The driving force of vegetation cover change in the upper reaches of Minjiang River was analyzed. The results showed the following. (1) The fractional vegetation cover in the upper reaches of Minjiang River from 2006 to 2016 was good, and the overall fractional vegetation cover was stable. The annual average fractional vegetation cover was 0.79, and the area with fractional vegetation cover > 0.8 accounted for 69% of the total area of the upper reaches of the Minjiang River. (2) The "5.12 Wenchuan earthquake" in 2008 seriously damaged the vegetation in the upper reaches of Minjiang River. The degraded area of fractional vegetation cover was 14013.41 km², which accounted for 57% of the total area of the upper reaches of the Minjiang River.The vegetation restoration condition in the upper reaches of Minjiang River from 2008 to 2016 was good.The area of fractional vegetation cover improvement was 17390.69 km², which accounted for 71% of the total area of the upper reaches of the Minjiang River. The fractional vegetation cover in the upper reaches of Minjiang River exceeded the pre-earthquake level. (3) The fractional vegetation cover in the upper reaches of Minjiang River was mainly affected by four factors:altitude, temperature, agrotype, and precipitation. Its explanatory power was > 40%, the interpretation of the Geomorphic type and vegetation types was between 20% and 40%, and the interpretation of slope and aspect was < 1%.