川西高原近20年植被覆盖遥感动态监测及其驱动力分析

The western Sichuan Plateau not only has unique topographical and geomorphological features but also plays a crucial role in the global climate system, especially in regulating the Asian monsoon climate through the dynamic changes of vegetation and the heat exchange mechanism. Based on the MODIS - NDVI vegetation index products and climate data from 2000 to 2017, this paper uses the dimidiate pixel model, trend analysis method and correlation analysis method to study the dynamic changes of fractional vegetation cover (FVC) and its relationship with climate factors in the western Sichuan Plateau area. The results show that: ① From 2000 to 2017, the annual interannual change rate of FVC in the western Sichuan Plateau area is 0.24%/a, and the change rate of FVC in the growing season (May - September) is 10.03%/a. Overall, FVC shows a trend of a small fluctuation increase from north to south, among which the increasing area accounts for 12.37% of the total area of the study area, while the decreasing area only accounts for 2.21%; ② According to the correlation between FVC and temperature and precipitation in the study area, it is found that the area where precipitation affects vegetation growth is more extensive and its promoting effect is more obvious. The area where temperature affects vegetation growth is relatively concentrated. The correlation between FVC in the growing season and the temperature in the same period is the highest, while there is a lag with precipitation, and the lag period is about 1 month; ③ The area where the change of FVC in the study area is affected by climate factors accounts for 4.15%. Among them, the area affected by the joint driving of temperature and precipitation accounts for 0.14% of the total area, the area mainly driven by temperature accounts for 1.98%, and the area mainly driven by precipitation accounts for 2.03%. The research results can provide a scientific basis for the relevant departments of the local government in the ecological environment quality evaluation and decision-making planning.

川西高原不仅拥有独特的地形与地貌特征，而且在全球气候系统中也发挥着至关重要的作用，特别是通过植被动态变化和热交换机制对亚洲季风气候起着调节作用。本文基于 2000-2017 年 MODIS-NDVI植被指数产品和气候数据，运用像元二分模型、趋势分析法以及相关分析法，对川西高原地区植被覆盖度.（FVC）的动态变化及其与气候因子的关系进行研究。结果表明：①在 2000-2017 年川西高原地区年际 FVC变化速率为 0.24 %/a，生长季（5-9 月）FVC 变化速率为 10.03 %/a，且 FVC 整体上呈现自北向南小幅度波动增加的趋势，其中增加的区域占研究区总面积的 12.37 %，而减少的区域仅占 2.21 %；②根据研究区 FVC与气温、降水的相关性发现降水对植被生长影响的区域更广泛，促进作用更明显。气温对植被生长影响的区域相对集中，生长季 FVC 与同期气温的相关性最高，而与降水存在滞后性，滞后期约为 1 个月；③研究.区 FVC 变化受气候因子影响的区域占 4.15 %。其中受气温和降水共同驱动影响的区域占总面积的 0.14 %，受气温为主要驱动影响的区域占 1.98 %，受降水为主要驱动影响的区域占 2.03 %。该研究成果可为地方政府有关部门对生态环境质量评价及决策规划提供科学依据。