近20年中国植被时空变化研究

Study on Spatiotemporal Change of Vegetation in China since 20 years

利用1982-1999年的全球AVHRR/NDVI数据,通过年次最大植被指数随时间的变化斜率、各种土地覆盖类型上植被指数的变化、绿波和褐波推移变化、典型地带植被时空序列变化分析,从遥感角度反映出近20年中国的植被时空动态变化规律。总体上看,中国大多数地区的NDVI呈不同程度的增加趋势,表明中国陆地生态系统植被生长状况没有发生显著恶化。生长季节的延长和生长加速是中国NDVI增加的主要原因,而温度上升和夏季降水量的增加以及农业生产活动的加强可能是其主要的驱动因子。中国NDVI变化趋势显示了较大的空间异质性,东部沿海地区、珠江三角洲、长江三角洲、京津唐等环渤海地区NDVI呈下降趋势或变化不明显;农业生产区和西部部分地区增加显著。这种空间异质性是由于城市化过程、农业生产活动、区域气候特征以及植被对气候变化的区域响应等综合因素作用的结果。

In this paper, the spatiotemporal change of vegetation in China since recent 20 years is researched based on remote sensing means using AVHRR/NDVI data during the period from 1982 to 1999 after analyzing the change slope of vegetation index with the time, vegetation indexes over various land cover types, change of brow and green waves and spatiotemporal change of vegetation in the typical zones. The results reveal that NDVI in the most regions in China has been generally in an increase trend in varying degrees since recent 20 years, which re- veals that there is no obvious vegetation degeneration in the terrestrial ecosystems in China. Prolonging of plant growth season and the acceleration of plant growth are the main factors bringing about the increase of NDVI in Chi- na, and the temperature increase, summer rainfall increase and intensification of farming activities are possibly the main driving factors. There is a significant spatial heterogeneity in the change trend of NDVI in China ： the NDVI is in a decrease trend or is slightly changed in the coastal regions in east China and the areas around Zhujiang delta, Yangtse delta and Bohai, and it, however, is significantly increased in the farming areas and some regions in west China. Such spatial heterogeneity is jointly affected by many factors, such as the urbanization process, farming activities, regional climate and regional response of vegetation to climate change.