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基于1999~2012年NDVI数据,结合气温和降水资料,运用GIS和RS技术,分析了西南地区近14a植被覆盖的时空变化特征及与气温、降水的关系。结果表明:(1)该区植被生长良好,各植被类型NDVI均呈显著增加趋势。空间整体表现为改善状态,改善面积远大于退化面积,严重退化区仅占1.18%。退化区分布于横断山地北部、四川盆地东部以及云贵高原中部。(2)植被覆盖变化将以良性发展为主,但强持续性的退化区和弱持续性的改善区应值得关注;强持续性的退化区主要分布在横断山地中北部、云贵高原中西部、若尔盖高原中部、四川盆地与若尔盖高原相交区域;草原强持续性的退化面积最大,针阔混交林强持续性的改善面积最大。(3)NDVI与温度存在明显的正相关关系,而与降水及干旱指数变化的关系不太明显,温度是影响该区植被变化的主要自然因素。
Based on the NDVI data from 1999 to 2012, combined with temperature and precipitation data, GIS and RS techniques were used to analyze the temporal and spatial variation characteristics of the near-14a vegetation cover in Southwest China and its relationship with temperature and precipitation. The results showed that: (1) The vegetation in this area grew well and the NDVI of each vegetation type showed a significant increase trend. The overall performance of the space is to improve the status, the improvement area is much larger than the degenerated area, and the severely degraded area only accounts for 1.18%. Degenerated areas are located in the northern part of Hengduan Mountains, the eastern Sichuan Basin and the central Yunnan-Guizhou Plateau. (2) The vegetation cover change will be dominated by benign development, but strong persistent degraded areas and weakly persistent improved areas should be noted; strong persistent degraded areas are mainly distributed in the northern part of Hengduan Mountains, the central and western Yunnan-Guizhou Plateau, Ruoergai plateau central, the Sichuan Basin and the Ruoergai Plateau intersect area; grassland strong persistent degradation area of the largest, continuous improvement of coniferous and broad-leaved forest to improve the largest area. (3) There is a clear positive correlation between NDVI and temperature, while the relationship between NDVI and precipitation and drought index is not obvious. Temperature is the main natural factor that affects vegetation change in this area.